oleg
/
monaco-editor
зеркало из https://github.com/microsoft/monaco-editor.git


			
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							<!DOCTYPE html>
<html lang="en">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
		<meta name="viewport" content="width=device-width" />

		<title>Monaco Editor Monarch</title>

		<link
			data-inline="yes-please"
			href="./monarch/monarch.css"
			rel="stylesheet"
		/>

		<link
			data-name="vs/editor/editor.main"
			rel="stylesheet"
			href="./node_modules/monaco-editor/dev/vs/editor/editor.main.css"
		/>
	</head>
	<body>
		<section id="monarch">
			<!--******************************************
    Main elements
**********************************************-->

			<div id="main">
				<div id="header">
					<img
						src="monarch/monarch-34px.png"
						id="logo"
						alt="Monarch-Logo"
					/>Monarch Documentation
				</div>

				<div id="leftPane">
					<div class="paneheader">
						Language syntax definition
						<span class="selectbox">
							Sample:
							<select id="sampleselect">
								<option>mylang</option>
								<option>java</option>
								<option>javascript</option>
								<option>python</option>
								<option>csharp</option>
								<option>xdot</option>
								<option>koka</option>
								<option disabled label=" "></option>
								<option>boogie</option>
								<option>chalice</option>
								<option>dafny</option>
								<option>formula</option>
								<option>smt2</option>
								<option>specsharp</option>
								<option>z3python</option>
								<option disabled label=" "></option>
								<option>html</option>
								<option>markdown</option>
								<option>ruby</option>
							</select>
						</span>
					</div>
					<div id="langPane"></div>
					<div id="commandbar">Generate:</div>
				</div>

				<div id="rightPane">
					<div class="paneheader">
						Language editor
						<span class="arrowdown" style="display: none"
							>&#x25BC;</span
						>
						<span class="selectbox">
							Theme:
							<select id="themeselect">
								<option>vs</option>
								<option>vs-dark</option>
								<option>hc-black</option>
							</select>
						</span>
					</div>
					<div id="editor"></div>
					<div id="monarchConsole"></div>
				</div>

				<!--******************************************
  Documentation
**********************************************-->
				<!--  <div id="footer">
    Documentation <span class="arrowdown">&#x25BC;</span>
  </div>-->
				<div id="documentation">
					<h2>
						Monarch: create declarative syntax highlighters using
						JSON
					</h2>
					<p>
						This document describes how to create a syntax
						highlighter using the Monarch library. This library
						allows you to specify an efficient syntax highlighter,
						using a declarative lexical specification (written as a
						JSON value). The specification is expressive enough to
						specify sophisticated highlighters with complex state
						transitions, dynamic brace matching, auto-completion,
						other language embeddings, etc. as shown in the
						'advanced' topic sections of this document. On a first
						read, it is safe to skip any section or paragraph marked
						as
						<span class="adv">(Advanced)</span> since many of the
						advanced features are rarely used in most language
						definitions.<br />
						&nbsp;&nbsp;&nbsp; &ndash; Daan Leijen.
					</p>

					<h2>Creating a language definition</h2>

					<p>
						A language definition is basically just a JSON value
						describing various properties of your language.
						Recognized attributes are:
					</p>

					<dl>
						<dt>ignoreCase</dt>
						<dd>
							(optional=<code>false</code>, boolean) Is the
							language case insensitive?. The regular expressions
							in the tokenizer use this to do case (in)sensitive
							matching, as well as tests in the
							<code>cases</code> construct.
						</dd>

						<dt>defaultToken</dt>
						<dd>
							(optional=<code>"source"</code>, string) The default
							token returned if nothing matches in the tokenizer.
							It can be convenient to set this to
							<code>"invalid"</code> during development of your
							colorizer to easily spot what is not matched yet.
						</dd>
						<dt id="brackets">brackets</dt>
						<dd>
							(optional, array of bracket definitions) This is
							used by the tokenizer to easily define matching
							braces. See
							<a href="#@brackets"
								><code class="dt">@brackets</code></a
							>
							and
							<a href="#bracket"
								><code class="dt">bracket</code></a
							>
							for more information. Each bracket definition is an
							array of 3 elements, or object, describing the
							<code>open</code> brace, the
							<code>close</code> brace, and the
							<code>token</code> class. The default definition is:
							<pre class="highlight">
    [ ['{','}','delimiter.curly'],
      ['[',']','delimiter.square'],
      ['(',')','delimiter.parenthesis'],
      ['&lt;','>','delimiter.angle'] ]</pre
							>
						</dd>
						<dt>tokenizer</dt>
						<dd>
							(required, object with states) This defines the
							tokenization rules &ndash; see the next section for
							a detailed description.
						</dd>
					</dl>

					<p>
						There are more attributes that can be specified which
						are described in the
						<a href="#moreattr">advanced attributes</a> section
						later in this document.
					</p>

					<h2>Creating a tokenizer</h2>

					<p>
						The <code>tokenizer</code> attribute describes how
						lexical analysis takes place, and how the input is
						divided into tokens. Each token is given a CSS class
						name which is used to render each token in the editor.
						Standard CSS token classes include:
					</p>
					<pre class="highlight">
identifier         entity           constructor
operators          tag              namespace
keyword            info-token       type
string             warn-token       predefined
string.escape      error-token      invalid
comment            debug-token
comment.doc        regexp
constant           attribute

delimiter .[curly,square,parenthesis,angle,array,bracket]
number    .[hex,octal,binary,float]
variable  .[name,value]
meta      .[content]</pre
					>

					<h3>States</h3>
					<p>
						A tokenizer consists of an object that defines states.
						The initial state of the tokenizer is the first state
						defined in the tokenizer. When a tokenizer is in a
						certain state, only the rules in that state will be
						applied. All rules are matched in order and when the
						first one matches its action is used to determine the
						token class. No further rules are tried. Therefore, it
						can be important to order the rules in a way that is
						most efficient, i.e. whitespace and identifiers first.
					</p>

					<p>
						<span class="adv">(Advanced)</span> A state is
						interpreted as dot (<code>.</code>) separated
						sub-states. When looking up the rules for a state, the
						tokenizer first tries the entire state name, and then
						looks at its parent until it finds a definition. For
						example, in our example, the states
						<code>"comment.block"</code> and
						<code>"comment.foo"</code> would both be handled by the
						<code>comment</code> rules. Hierarchical state names can
						be used to maintain complex lexer states, as shown for
						example in the section on
						<a href="#htmlembed">complex embeddings</a>.
					</p>

					<h3>Rules</h3>
					<p>
						Each state is defined as an array of rules which are
						used to match the input. Rules can have the following
						form:
					</p>
					<dl>
						<dt>[<em>regex</em>, <em>action</em>]</dt>
						<dd>
							Shorthand for
							<code
								>{ regex: <em>regex</em>, action:
								<em>action</em> }</code
							>
						</dd>

						<dt>
							[<em>regex</em>, <em>action</em>, <em>next</em>]
						</dt>
						<dd>
							Shorthand for
							<code
								>{ regex: <em>regex</em>, action:
								<em>action</em>{next: <em>next</em>} }</code
							>
						</dd>

						<dt>
							{regex: <em>regex</em>, action: <em>action</em> }
						</dt>
						<dd>
							When <code><em>regex</em></code> matches against the
							current input, then <code><em>action</em></code> is
							applied to set the token class. The regular
							expression <code><em>regex</em></code> can be either
							a regular expression (using
							<code>/<em>regex</em>/</code>), or a string
							representing a regular expression. If it starts with
							a <code>^</code> character, the expression only
							matches at the start of a source line. The
							<code>$</code> can be used to match against the end
							of a source line. Note that the tokenizer is not
							called when the end of the line is already reached,
							and the empty pattern <code>/$/</code> will
							therefore never match (but see
							<a href="#@eos"><code class="dt">'@eos'</code></a>
							too). Inside a regular expression, you can reference
							a string attribute named
							<code><em>attr</em></code> as
							<code>@<em>attr</em></code
							>, which is automatically expanded. This is used in
							the standard example to share the regular expression
							for escape sequences using
							<code>'@escapes'</code> inside the regular
							expression for characters and strings.

							<p>
								Regular expression primer: common regular
								expression escapes we use are
								<code>\d</code> for <code>[0-9]</code>,
								<code>\w</code> for <code>[a-zA-Z0-9_]</code>,
								and <code>\s</code> for <code>[ \t\r\n]</code>.
								The notation
								<code><em>regex</em>{<em>n</em>}</code> stands
								for <code><em>n</em></code> occurrences of
								<code><em>regex</em></code
								>. Also, we use
								<code>(?=<em>regex</em>)</code> for
								non-consuming `followed by
								<code><em>regex</em></code
								>', <code>(?!<em>regex</em>)</code> for `not
								followed by', and
								<code>(?:<em>regex</em>)</code> for a
								non-capturing group (i.e. cannot use
								<code>$<em>n</em></code> to refer to it).
							</p>
						</dd>
						<dt>{ include: <em>state</em> }</dt>
						<dd>
							Used for nice organization of your rules and expands
							to all the rules defined in
							<code><em>state</em></code
							>. This is pre-expanded and has no influence on
							performance. Many samples include the
							<code>'@whitespace'</code> state for example.
						</dd>
					</dl>

					<h3>Actions</h3>
					<p>
						An action determines the resulting token class. An
						action can have the following forms:
					</p>
					<dl>
						<dt><em>string</em></dt>
						<dd>
							Shorthand for
							<code>{ token: <em>string</em> }</code>.
						</dd>
						<dt>[<em>action1</em>,...,<em>actionN</em>]</dt>
						<dd>
							An array of N actions. This is only allowed when the
							regular expression consists of exactly N groups (ie.
							parenthesized parts). Due to the way the tokenizer
							works, you must define the groups in such a way that
							all groups appear at top-level and encompass the
							entire input, for example, we could define
							characters with an ascii code escape sequence as:
							<pre class="highlight">
/(')(\\(?:[abnfrt]|[xX][0-9]{2}))(')/, ['string','string.escape','string']]</pre
							>
							<p>
								Note how we used a non-capturing group using
								<code>(?: )</code> in the inner group
							</p>
						</dd>

						<dt id="token">{ token: <em>tokenclass</em> }</dt>
						<dd>
							An object that defines the token class used with CSS
							rendering. Common token classes are for example
							<code>&apos;keyword&apos;</code>,
							<code>&apos;comment&apos;</code> or
							<code>&apos;identifier&apos;</code>. You can use a
							dot to use hierarchical CSS names, like
							<code>&apos;type.identifier&apos;</code> or
							<code>&apos;string.escape&apos;</code>. You can also
							include <code>$</code> patterns that are substituted
							with a captured group from the matched input or the
							tokenizer state. The patterns are described in the
							<a href="#pattern">guard section</a> of this
							document. There are some special token classes:
							<dl>
								<dt id="@brackets">"@brackets"</dt>
								<dd>or</dd>
								<dt>"@brackets.<em>tokenclass</em></dt>
								<dd>
									Signifies that brackets were tokenized. The
									token class for CSS is determined by the
									token class defined in the
									<a href="#brackets"
										><code>brackets</code></a
									>
									attribute (together with
									<code><em>tokenclass</em></code> if
									present). Moreover,
									<a href="#bracket"
										><code class="dt">bracket</code></a
									>
									attribute is set such that the editor
									matches the braces (and does auto
									indentation). For example:
									<pre class="highlight">
[/[{}()\[\]]/, '@brackets']</pre
									>
								</dd>

								<dt id="@rematch">"@rematch"</dt>
								<dd>
									<span class="adv">(Advanced)</span> Backs up
									the input and re-invokes the tokenizer. This
									of course only works when a state change
									happens too (or we go into an infinite
									recursion), so this is usually used in
									combination with the
									<code class="dt">next</code> attribute. This
									can be used for example when you are in a
									certain tokenizer state and want to get out
									when seeing certain end markers but don't
									want to consume them while being in that
									state. See also
									<a href="#nextEmbedded"
										><code class="dt">nextEmbedded</code></a
									>.
								</dd>
							</dl>
							<p>
								An action object can contain more fields that
								influence the state of a lexer. The following
								attributes are recognized:
							</p>
							<dl>
								<dt id="next">next: <em>state</em></dt>
								<dd>
									(string) If defined it pushes the current
									state onto the tokenizer stack and makes
									<code><em>state</em></code> the current
									state. This can be used for example to start
									tokenizing a block comment:
									<pre class="highlight">
['/\\*', 'comment', '@comment' ]</pre
									>
									<p>Note that this is a shorthand for</p>
									<pre class="highlight">
{ regex: '/\\*', action: { token: 'comment', next: '@comment' } }</pre
									>
									<p>
										Here the matched <code>/*</code> is
										given the <code>"comment"</code> token
										class, and the tokenizer proceeds with
										matching the input using the rules in
										state <code>@comment</code>.
									</p>
									<p>
										There are a few special states that can
										be used for the
										<code>next</code> attribute:
									</p>
									<dl>
										<dt>"@pop"</dt>
										<dd>
											Pops the tokenizer stack to return
											to the previous state. This is used
											for example to return from block
											comment tokenizing after seeing the
											end marker:
											<pre class="highlight">
['\\*/', 'comment', '@pop']</pre
											>
										</dd>

										<dt>"@push"</dt>
										<dd>
											Pushes the current state and
											continues in the current state. Nice
											for doing nested block comments when
											seeing a comment begin marker, i.e.
											in the
											<code>@comment</code> state, we can
											do:
											<pre class="highlight">
['/\\*', 'comment', '@push']</pre
											>
										</dd>

										<dt id="popall">"@popall"</dt>
										<dd>
											Pops everything from tokenizer stack
											and returns to the top state. This
											can be used during recovery to
											'jump' back to the initial state
											from a deep nesting level.
										</dd>
									</dl>
								</dd>

								<dt id="switchTo">switchTo: <em>state</em></dt>
								<dd>
									<span class="adv">(Advanced)</span> Switch
									to <code><em>state</em></code> without
									changing the stack.
								</dd>

								<dt id="goBack">goBack: <em>number</em></dt>
								<dd>
									<span class="adv">(Advanced)</span> Back up
									the input by
									<code><em>number</em></code> characters.
								</dd>

								<dt id="bracket">bracket: <em>kind</em></dt>
								<dd>
									<span class="adv">(Advanced)</span> The
									<code><em>kind</em></code> can be either
									<code>'@open'</code> or
									<code>'@close'</code>. This signifies that a
									token is either an open or close brace. This
									attribute is set automatically if the token
									class is
									<a href="#@brackets"
										><code class="dt">@brackets</code></a
									>. The editor uses the bracket information
									to show matching braces (where an open
									bracket matches with a close bracket if
									their token classes are the same). Moreover,
									when a user opens a new line the editor will
									do auto indentation on open braces.
									Normally, this attribute does not need to be
									set if you are using the
									<a href="#brackets"
										><code class="dt">brackets</code></a
									>
									attribute and it is only used for complex
									brace matching. This is discussed further in
									the next section on
									<a href="#complexmatch"
										>advanced brace matching</a
									>.
								</dd>

								<dt id="nextEmbedded">
									nextEmbedded: <em>langId</em>
									<span>or</span> '@pop'
								</dt>
								<dd>
									<span class="adv">(Advanced)</span>
									Signifies to the editor that this token is
									followed by code in another language
									specified by the <code><em>langId</em></code
									>, i.e. for example <code>javascript</code>.
									Internally, our syntax highlighter keeps
									tokenizing the source until it finds an an
									ending sequence. At that point, you can use
									<code class="dt">nextEmbedded</code> with a
									<code class="dt">'@pop'</code> value to pop
									out of the embedded mode again.
									<code class="dt">nextEmbedded</code> usually
									needs a
									<code class="dt">next</code> attribute to
									switch to a state where we can tokenize the
									foreign code. As an example, here is how we
									could support CSS fragments in our language:
									<pre class="highlight">
root: [
  [/&lt;style\s*>/,   { token: 'keyword', bracket: '@open'
                   , next: '@css_block', nextEmbedded: 'text/css' }],

  [/&lt;\/style\s*>/, { token: 'keyword', bracket: '@close' }],
  ...
],

css_block: [
  [/[^"&lt;]+/, ''],
  [/&lt;\/style\s*>/, { token: '@rematch', next: '@pop', nextEmbedded: '@pop' }],
  [/"/, 'string', '@string' ],
  [/&lt;/, '']
],</pre
									>
									<p>
										Note how we switch to the
										<code>css_block</code> state for
										tokenizing the CSS source. Also inside
										the CSS we use the
										<code>@string</code> state to tokenize
										CSS strings such that we do not stop the
										CSS block when we find
										<code>&lt;/style&gt;</code> inside a
										string. When we find the closing tag, we
										also
										<a href="#@pop"
											><code class="dt">"@pop"</code></a
										>
										the state to get back to normal
										tokenization. Finally, we need to
										<a href="#@rematch"
											><code class="dt"
												>"@rematch"</code
											></a
										>
										the token (in the
										<code>root</code> state) since the
										editor ignores our token classes until
										we actually exit the embedded mode. See
										also a later section on
										<a href="#htmlembed"
											>complex dynamic embeddings</a
										>. (Bug: you can only start an embedded
										section if the you consume characters at
										the start of the embedded block (like
										consuming the
										<code>&lt;style&gt;</code> tag) (Aug
										2012))
									</p>
								</dd>

								<dt id="log">log: <em>message</em></dt>
								<dd>
									Used for debugging. Logs
									<code><em>message</em></code> to the console
									window in the browser (press F12 to see it).
									This can be useful to see if a certain
									action is executing. For example:
									<pre class="highlight">
[/\d+/, { token: 'number', log: 'found number $0 in state $S0' } ]</pre
									>
								</dd>
								<dd>&nbsp;</dd>
								<!--
        <dt>bracketType: <em>bracketType</em></dt><dd>If <code>token</code> is <code>"@brackets"</code>, this attribute can specify for an arbitrary matched input (like <code>"end"</code>), which is not present in the <code>brackets</code> attribute, what kind of bracket this is: <code>"@open"</code>, <code>"@close"</code>, or <code>"@none"</code>.</dd>
      -->
							</dl>
						</dd>

						<dt id="cases">
							{ cases: { <em>guard1</em>: <em>action1</em>, ...,
							<em>guardN</em>: <em>actionN</em> } }
						</dt>
						<dd>
							The final kind of action object is a cases
							statement. A cases object contains an object where
							each field functions as a guard. Each guard is
							applied to the matched input and as soon as one of
							them matches, the corresponding action is applied.
							Note that since these are actions themselves, cases
							can be nested. Cases are used for efficiency: for
							example, we match for identifiers and then test
							whether the identifier is possibly a keyword or
							builtin function:
							<pre class="highlight">
[/[a-z_\$][a-zA-Z0-9_\$]*/,
  { cases: { '@typeKeywords': 'keyword.type'
           , '@keywords': 'keyword'
           , '@default': 'identifier' }
  }
]</pre
							>
							<p>The guards can consist of:</p>
							<dl>
								<dt>"@<em>keywords</em>"</dt>
								<dd>
									The attribute
									<code><em>keywords</em></code> must be
									defined in the language object and consist
									of an array of strings. The guard succeeds
									if the matched input matches any of the
									strings. (Note: all cases are pre-compiled
									and the list is tested using efficient hash
									maps). <span class="adv">Advanced</span>: if
									the attribute refers to a single string
									(instead of an array) it is compiled to a
									regular expression which is tested against
									the matched input.
								</dd>
								<dt>"@default"</dt>
								<dd>
									(or <code>"@"</code> or <code>""</code>) The
									default guard that always succeeds.
								</dd>
								<dt id="@eos">"@eos"</dt>
								<dd>
									Succeeds if the matched input has reached
									the end of the line.
								</dd>
								<dt>"<em>regex</em>"</dt>
								<dd>
									If the guard does not start with a
									<code>@</code> (or <code>$</code>) character
									it is interpreted as a regular expression
									that is tested against the matched input.
									Note: the <code><em>regex</em></code> is
									prefixed with <code>^</code> and postfixed
									with <code>$</code> so it must match the
									matched input entirely. This can be used for
									example to test for specific inputs, here is
									an example from the Koka language which uses
									this to enter various tokenizer states based
									on the declaration:
									<pre class="highlight">
[/[a-z](\w|\-[a-zA-Z])*/,
  { cases:{ '@keywords': {
               cases: { 'alias'              : { token: 'keyword', next: '@alias-type' }
                      , 'struct'             : { token: 'keyword', next: '@struct-type' }
                      , 'type|cotype|rectype': { token: 'keyword', next: '@type' }
                      , 'module|as|import'   : { token: 'keyword', next: '@module' }
                      , '@default'           : 'keyword' }
            }
          , '@builtins': 'predefined'
          , '@default' : 'identifier' }
  }
]
</pre
									>
									<p>
										Note the use of nested cases to improve
										efficiency. Also, the library recognizes
										simple regular expressions like the ones
										above and compiles them efficiently. For
										example, the list of words
										<code>type|cotype|rectype</code> is
										tested using a Javascript
										hashmap/object.
									</p>
								</dd>
							</dl>
							<p id="pattern">
								<span class="adv">(Advanced)</span> In general,
								a guard has the form
								<code class="dt"
									>[<em>pat</em>][<em>op</em>]<em
										>match</em
									></code
								>, with an optional pattern, and operator (which
								are <code>$#</code> and <code>~</code> by
								default). The pattern can be any of:
							</p>
							<dl>
								<dt>$#</dt>
								<dd>
									(default) The matched input (or the group
									that matched when the action is an array).
								</dd>
								<dt>$<em>n</em></dt>
								<dd>
									The <em>n</em>th group of the matched input,
									or the entire matched input for
									<code>$0</code>.
								</dd>
								<dt>$S<em>n</em></dt>
								<dd>
									The <em>n</em>th part of the state, i.e.
									<code>$S2</code> returns <code>foo</code> in
									a state <code>@tag.foo</code>. Use
									<code>$S0</code> for the full state name.
								</dd>
							</dl>
							<p>
								The above patterns can actually occur in many
								attributes and are automatically expanded.
								Attributes where these patterns expand are
								<a href="#token"
									><code class="dt">token</code></a
								>,
								<a href="#next"><code class="dt">next</code></a
								>,
								<a href="#nextEmbedded"
									><code class="dt">nextEmbedded</code></a
								>,
								<a href="#switchTo"
									><code class="dt">switchTo</code></a
								>, and
								<a href="#log"><code class="dt">log</code></a
								>. Also, these patterns are expanded in the
								<code class="dt"><em>match</em></code> part of a
								guard.
							</p>

							<p>
								The guard operator <code><em>op</em></code> and
								<code><em>match</em></code> can be any of:
							</p>
							<dl>
								<dt>
									~<em>regex</em>
									<span style="color: black">or</span> !~<em
										>regex</em
									>
								</dt>
								<dd>
									(default for <code><em>op</em></code> is
									<code>~</code>) Tests
									<code><em>pat</em></code> against the
									regular expression or its negation.
								</dd>
								<dt>
									@<em>attribute</em>
									<span style="color: black">or</span> !@<em
										>attribute</em
									>
								</dt>
								<dd>
									Tests whether <code><em>pat</em></code> is
									an element (<code>@</code>), or not an
									element (<code>!@</code>), of an array of
									strings defined by
									<code><em>attribute</em></code
									>.
								</dd>
								<dt>
									==<em>str</em>
									<span style="color: black">or</span> !=<em
										>str</em
									>
								</dt>
								<dd>
									Tests if <code><em>pat</em></code> is equal
									or unequal to the given string
									<code><em>str</em></code
									>.
								</dd>
							</dl>
							<p>
								For example, here is how to check if the second
								group is not equal to
								<code>foo</code> or <code>bar</code>:
								<code>$2!~foo|bar</code>, or if the first
								captured group equals the name of the current
								lexer state: <code>$1==$S0</code>.
							</p>
							<p>
								If both <code><em>op</em></code> and
								<code><em>match</em></code> are empty and there
								is just a pattern, then the guard succeeds if
								the pattern is non-empty. This can be used for
								example to improve efficiency. In the Koka
								language, an upper case identifier followed by a
								dot is module name, but without the following
								dot it is a constructor. This can be matched for
								in one go using:
							</p>
							<pre class="highlight">
[/([A-Z](?:[a-zA-Z0-9_]|\-[a-zA-Z])*)(\.?)/,
  { cases: { '$2'      : ['identifier.namespace','keyword.dot']
           , '@default': 'identifier.constructor' }}
]</pre
							>
						</dd>
					</dl>

					<p>&nbsp;</p>
					<h2 id="complexmatch">Advanced: complex brace matching</h2>

					<p>
						This section gives some advanced examples of brace
						matching using the
						<a href="#bracket"><code class="dt">bracket</code></a>
						attribute in an action. Usually, we can match braces
						just using the
						<a href="#brackets"><code>brackets</code></a> attribute
						in combination with the
						<a href="#@brackets"><code>@brackets</code></a> token
						class. But sometimes we need more fine grained control.
						For example, in Ruby many declarations like
						<code class="token keyword">class</code> or
						<code class="token keyword">def</code> are ended with
						the <code class="token keyword">end</code> keyword. To
						make them match, we all give them the same token class
						(<code>keyword.decl</code>) and use bracket
						<code>@close</code> for
						<code class="token keyword">end</code> and
						<code>@open</code> for all declarations:
					</p>
					<pre class="highlight">
declarations: ['class','def','module', ... ]

tokenizer: {
  root: {
    [/[a-zA-Z]\w*/,
      { cases: { 'end'          : { token: 'keyword.decl', bracket: '@close' }
               , '@declarations': { token: 'keyword.decl', bracket: '@open' }
               , '@keywords'    : 'keyword'
               , '@default'     : 'identifier' }
      }
    ],</pre
					>
					<p>
						Note that to make <em>outdentation</em> work on the
						<code>end</code> keyword, you would also need to include
						the <code>'d'</code> character in the
						<a href="#outdentTriggers"
							><code class="dt">outdentTriggers</code></a
						>
						string.
					</p>

					<p>
						Another example of complex matching is HTML where we
						would like to match starting tags, like
						<code>&lt;div&gt;</code> with an ending tag
						<code>&lt;/div&gt;</code>. To make an end tag only match
						its specific open tag, we need to dynamically generate
						token classes that make the braces match correctly. This
						can be done using <code>$</code> expansion in the token
						class:
					</p>
					<pre class="highlight">
tokenizer: {
  root: {
     [/&lt;(\w+)(>?)/,   { token: 'tag-$1', bracket: '@open'  }],
     [/&lt;\/(\w+)\s*>/, { token: 'tag-$1', bracket: '@close' }],</pre
					>
					<p>
						Note how we captured the actual tag name as a group and
						used that to generate the right token class. Again, to
						make outdentation work on the closing tag, you would
						also need to include the
						<code>'>'</code> character in the
						<a href="#outdentTriggers"
							><code class="dt">outdentTriggers</code></a
						>
						string.
					</p>

					<p>
						A final advanced example of brace matching is Visual
						Basic where declarations like
						<code class="token keyword">Structure</code> are matched
						with end declarations as
						<code class="token keyword">End Structure</code>. Just
						like HTML we need to dynamically set token classes so
						that an <code class="token keyword">End Enum</code> does
						not match with a
						<code class="token keyword">Structure</code>. A tricky
						part is that we now need to match multiple tokens at
						once, and we match a construct like
						<code class="token keyword">End Enum</code> as one
						closing token, but non declaration endings, like
						<code class="token keyword">End</code>
						<code class="token constructor"> Foo</code>, as three
						tokens:
					</p>
					<pre class="highlight">
decls: ["Structure","Class","Enum","Function",...],

tokenizer: {
  root: {
     [/(End)(\s+)([A-Z]\w*)/, { cases: { '$3@decls': { token: 'keyword.decl-$3', bracket: '@close'},
                                         '@default': ['keyword','white','identifier.invalid'] }}],
     [/[A-Z]\w*/, { cases: { '@decls'  : { token: 'keyword.decl-$0', bracket: '@open' },
                             '@default': 'constructor' } }],</pre
					>
					<p>
						Note how we used <code>$3</code> to first test if the
						third group is a declaration, and then use
						<code>$3</code> in the <code>token</code> attribute to
						generate a declaration specific token class (so we match
						correctly). Also, to make outdentation work correctly,
						we would need to include all the ending characters of
						the declarations in the
						<a href="#outdentTriggers"
							><code class="dt">outdentTriggers</code></a
						>
						string.
					</p>

					<p>&nbsp;</p>
					<h2 id="moreattr">
						Advanced: more attributes on the language definition
					</h2>
					<p>
						Here are more advanced attributes that can be defined in
						the language definition:
					</p>
					<dl>
						<dt>tokenPostfix</dt>
						<dd>
							(optional=<code>"." + name</code>, string) Optional
							postfix attached to all returned tokens. By default
							this attaches the language name so in the CSS you
							can refer to your specific language. For example,
							for the Java language, we could use
							<code>.identifier.java</code> to target all Java
							identifiers specifically in CSS.
						</dd>

						<dt>start</dt>
						<dd>
							(optional, string) The start state of the tokenizer.
							By default, this is the first entry in the tokenizer
							attribute.
						</dd>

						<dt id="outdentTriggers">outdentTriggers</dt>
						<dd>
							(optional, string) Optional string that defines
							characters that when typed could cause
							<em>outdentation</em>. This attribute is only used
							when using advanced brace matching in combination
							with the
							<a href="#bracket"
								><code class="dt">bracket</code></a
							>
							attribute. By default it always includes the last
							characters of the closing brackets in the
							<a href="#brackets"
								><code class="dt">brackets</code></a
							>
							list. Outdentation happens when the user types a
							closing bracket word on an line that starts with
							only white space. If the closing bracket matches a
							open bracket it is indented to the same amount of
							that bracket. Usually, this causes the bracket to
							outdent. For example, in the Ruby language, the
							<code class="token keyword">end</code> keyword would
							match with an open declaration like
							<code class="token keyword">def</code> or
							<code class="token keyword">class</code>. To make
							outdentation happen though, we would need to include
							the <code>d</code> character in the
							<a href="#outdentTriggers"
								><code class="dt">outdentTriggers</code></a
							>
							attribute so it is checked when the users type
							<code class="token keyword">end</code>:
							<pre class="highlight">outdentTriggers: 'd',</pre>
						</dd>
					</dl>

					<p>&nbsp;</p>
					<h2 id="htmlembed">
						&Uuml;ber Advanced: complex embeddings with dynamic end
						tags
					</h2>

					<p>
						Many times, embedding other language fragments is easy
						as shown in the earlier CSS example, but sometimes it is
						more dynamic. For example, in HTML we would like to
						start embeddings on a
						<code class="token tag html">script</code> tag and
						<code class="token tag html">style</code> tag. By
						default, the script language is
						<code>javascript</code> but if the
						<code class="token key js">type</code> attribute is set,
						that defines the script language mime type. First, we
						define general tag open and close rules:
					</p>
					<pre class="highlight">
[/&lt;(\w+)/,       { token: 'tag.tag-$1', bracket: '@open', next: '@tag.$1' }],
[/&lt;\/(\w+)\s*>/, { token: 'tag.tag-$1', bracket: '@close' } ],</pre
					>
					<p>
						Here, we use the <code>$1</code> to capture the open tag
						name in both the token class and the next state. By
						putting the tag name in the token class, the brace
						matching will match and auto indent corresponding tags
						automatically. Next we define the
						<code>@tag</code> state that matches content within an
						HTML tag. Because the open tag rule will set the next
						state to <code>@tag.<em>tagname</em></code
						>, this will match the <code>@tag</code> state due to
						dot seperation.
					</p>
					<pre class="highlight">
tag: [
  [/[ \t\r\n]+/, 'white'],
  [/(type)(\s*=\s*)(['"])([^'"]+)(['"])/, [ 'attribute', 'delimiter', 'string', // todo: should match up quotes properly
                                            {token: 'string', switchTo: '@tag.$S2.$4' },
                                            'string'] ],
  [/(\w+)(\s*=\s*)(['"][^'"]+['"])/, ['keyword', 'delimiter', 'string' ]],
  [/>/, { cases: { '$S2==style' : { token: 'delimiter', switchTo: '@embedded.$S2', nextEmbedded: 'text/css'}
                 , '$S2==script': { cases: { '$S3'     : { token: 'delimiter', switchTo: '@embedded.$S2', nextEmbedded: '$S3' },
                                             '@default': { token: 'delimiter', switchTo: '@embedded.$S2', nextEmbedded: 'javascript' } }
                 , '@default'   : { token: 'delimiter', next: '@pop' } } }]
  [/[^>]/,'']  // catch all
],</pre
					>
					<p>
						Inside the <code>@tag.<em>tagname</em></code> state, we
						access the <code><em>tagname</em></code> through
						<code>$S2</code>. This is used to test if the tag name
						matches a script of style tag, in which case we start an
						embedded mode. We also need
						<a href="#switchTo"><code class="dt">switchTo</code></a>
						here since we do not want to get back to the
						<code>@tag</code> state at that point. Also, on a
						<code class="token key js">type</code> attribute we
						extend the state to
						<code>@tag.<em>tagname</em>.<em>mimetype</em></code>
						which allows us to access the mime type as
						<code>$S3</code> if it was set. This is used to
						determine the script language (or default to
						<code>javascript</code>). Finally, the script and style
						start an embedded mode and switch to a state
						<code>@embedded.<em>tagname</em></code
						>. The tag name is included in the state so we can scan
						for exactly a matching end tag:
					</p>
					<pre class="highlight">
embedded: [
  [/[^"&lt;]+/, ''],
  [/&lt;\/(\w+)\s*>/, { cases: { '$1==$S2' : { token: '@rematch', next: '@pop', nextEmbedded: '@pop' },
                              '@default': '' } }],
  [/"/, 'string', '@string' ],
  [/&lt;/, '']
],</pre
					>
					<p>
						Only when we find a matching end tag (outside a string),
						<code>$1==$S2</code>, we pop the state and exit the
						embedded mode. Note that we need
						<a href="#@rematch"><code class="dt">@rematch</code></a>
						since the editor is ignoring our token classes until we
						actually exit the embedded mode (and we handle the close
						tag again in the <code>@root</code> state).
					</p>

					<p>&nbsp;</p>
					<h2 id="inspectingtokens">Inspecting Tokens</h2>

					<p>
						Monaco provides an <code>Inspect Tokens</code> tool in
						browsers to help identify the tokens parsed from source
						code.
					</p>
					<p>To activate:</p>
					<ol>
						<li>
							Press <kbd>F1</kbd> while focused on a Monaco
							instance
						</li>
						<li>
							Trigger the
							<code>Developer: Inspect Tokens</code> option
						</li>
					</ol>

					<p>
						This will show a display over the currently selected
						token for its language, token type, basic font style and
						colors, and selector you can target in your editor
						themes.
					</p>

					<p>&nbsp;</p>
					<h2>Additional Examples</h2>

					<p>
						Additional examples can be found in the
						<code class="dt">src/basic-languages</code> folder of
						the
						<a href="https://github.com/microsoft/monaco-editor"
							>monaco-editor</a
						>
						repo.
					</p>
				</div>
				<!-- documentation -->
			</div>
			<!-- main -->

			<!--******************************************
    Samples are included as PRE elements
**********************************************-->
			<div id="samples" style="display: none">
				<pre id="mylang-sample">
// Type source code in your language here...
class MyClass {
  @attribute
  void main() {
    Console.writeln( "Hello Monarch world\n");
  }
}
</pre
				>
				<pre id="mylang">
// Create your own language definition here
// You can safely look at other samples without losing modifications.
// Modifications are not saved on browser refresh/close though -- copy often!
return {
  // Set defaultToken to invalid to see what you do not tokenize yet
  // defaultToken: 'invalid',

  keywords: [
    'abstract', 'continue', 'for', 'new', 'switch', 'assert', 'goto', 'do',
    'if', 'private', 'this', 'break', 'protected', 'throw', 'else', 'public',
    'enum', 'return', 'catch', 'try', 'interface', 'static', 'class',
    'finally', 'const', 'super', 'while', 'true', 'false'
  ],

  typeKeywords: [
    'boolean', 'double', 'byte', 'int', 'short', 'char', 'void', 'long', 'float'
  ],

  operators: [
    '=', '&gt;', '&lt;', '!', '~', '?', ':', '==', '&lt;=', '&gt;=', '!=',
    '&amp;&amp;', '||', '++', '--', '+', '-', '*', '/', '&amp;', '|', '^', '%',
    '&lt;&lt;', '&gt;&gt;', '&gt;&gt;&gt;', '+=', '-=', '*=', '/=', '&amp;=', '|=', '^=',
    '%=', '&lt;&lt;=', '&gt;&gt;=', '&gt;&gt;&gt;='
  ],

  // we include these common regular expressions
  symbols:  /[=&gt;&lt;!~?:&amp;|+\-*\/\^%]+/,

  // C# style strings
  escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,

  // The main tokenizer for our languages
  tokenizer: {
    root: [
      // identifiers and keywords
      [/[a-z_$][\w$]*/, { cases: { '@typeKeywords': 'keyword',
                                   '@keywords': 'keyword',
                                   '@default': 'identifier' } }],
      [/[A-Z][\w\$]*/, 'type.identifier' ],  // to show class names nicely

      // whitespace
      { include: '@whitespace' },

      // delimiters and operators
      [/[{}()\[\]]/, '@brackets'],
      [/[&lt;&gt;](?!@symbols)/, '@brackets'],
      [/@symbols/, { cases: { '@operators': 'operator',
                              '@default'  : '' } } ],

      // @ annotations.
      // As an example, we emit a debugging log message on these tokens.
      // Note: message are supressed during the first load -- change some lines to see them.
      [/@\s*[a-zA-Z_\$][\w\$]*/, { token: 'annotation', log: 'annotation token: $0' }],

      // numbers
      [/\d*\.\d+([eE][\-+]?\d+)?/, 'number.float'],
      [/0[xX][0-9a-fA-F]+/, 'number.hex'],
      [/\d+/, 'number'],

      // delimiter: after number because of .\d floats
      [/[;,.]/, 'delimiter'],

      // strings
      [/"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/"/,  { token: 'string.quote', bracket: '@open', next: '@string' } ],

      // characters
      [/'[^\\']'/, 'string'],
      [/(')(@escapes)(')/, ['string','string.escape','string']],
      [/'/, 'string.invalid']
    ],

    comment: [
      [/[^\/*]+/, 'comment' ],
      [/\/\*/,    'comment', '@push' ],    // nested comment
      ["\\*/",    'comment', '@pop'  ],
      [/[\/*]/,   'comment' ]
    ],

    string: [
      [/[^\\"]+/,  'string'],
      [/@escapes/, 'string.escape'],
      [/\\./,      'string.escape.invalid'],
      [/"/,        { token: 'string.quote', bracket: '@close', next: '@pop' } ]
    ],

    whitespace: [
      [/[ \t\r\n]+/, 'white'],
      [/\/\*/,       'comment', '@comment' ],
      [/\/\/.*$/,    'comment'],
    ],
  },
};
</pre
				>

				<pre id="java-sample">
// Type source code in your Java here...
public class HelloWorld {
   public static void main(String[] args) {
      System.out.println("Hello, World");
   }
}
</pre
				>
				<pre id="java">
// Difficulty: "Easy"
// Language definition for Java
return {
	defaultToken: '',
	tokenPostfix: '.java',

	keywords: [
		'abstract', 'continue', 'for', 'new', 'switch', 'assert', 'default',
		'goto', 'package', 'synchronized', 'boolean', 'do', 'if', 'private',
		'this', 'break', 'double', 'implements', 'protected', 'throw', 'byte',
		'else', 'import', 'public', 'throws', 'case', 'enum', 'instanceof', 'return',
		'transient', 'catch', 'extends', 'int', 'short', 'try', 'char', 'final',
		'interface', 'static', 'void', 'class', 'finally', 'long', 'strictfp',
		'volatile', 'const', 'float', 'native', 'super', 'while', 'true', 'false'
	],

	operators: [
		'=', '&gt;', '&lt;', '!', '~', '?', ':',
		'==', '&lt;=', '&gt;=', '!=', '&amp;&amp;', '||', '++', '--',
		'+', '-', '*', '/', '&amp;', '|', '^', '%', '&lt;&lt;',
		'&gt;&gt;', '&gt;&gt;&gt;', '+=', '-=', '*=', '/=', '&amp;=', '|=',
		'^=', '%=', '&lt;&lt;=', '&gt;&gt;=', '&gt;&gt;&gt;='
	],

	// we include these common regular expressions
	symbols: /[=&gt;&lt;!~?:&amp;|+\-*\/\^%]+/,
	escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,
	digits: /\d+(_+\d+)*/,
	octaldigits: /[0-7]+(_+[0-7]+)*/,
	binarydigits: /[0-1]+(_+[0-1]+)*/,
	hexdigits: /[[0-9a-fA-F]+(_+[0-9a-fA-F]+)*/,

	// The main tokenizer for our languages
	tokenizer: {
		root: [
			// identifiers and keywords
			[/[a-zA-Z_$][\w$]*/, {
				cases: {
					'@keywords': { token: 'keyword.$0' },
					'@default': 'identifier'
				}
			}],

			// whitespace
			{ include: '@whitespace' },

			// delimiters and operators
			[/[{}()\[\]]/, '@brackets'],
			[/[&lt;&gt;](?!@symbols)/, '@brackets'],
			[/@symbols/, {
				cases: {
					'@operators': 'delimiter',
					'@default': ''
				}
			}],

			// @ annotations.
			[/@\s*[a-zA-Z_\$][\w\$]*/, 'annotation'],

			// numbers
			[/(@digits)[eE]([\-+]?(@digits))?[fFdD]?/, 'number.float'],
			[/(@digits)\.(@digits)([eE][\-+]?(@digits))?[fFdD]?/, 'number.float'],
			[/0[xX](@hexdigits)[Ll]?/, 'number.hex'],
			[/0(@octaldigits)[Ll]?/, 'number.octal'],
			[/0[bB](@binarydigits)[Ll]?/, 'number.binary'],
			[/(@digits)[fFdD]/, 'number.float'],
			[/(@digits)[lL]?/, 'number'],

			// delimiter: after number because of .\d floats
			[/[;,.]/, 'delimiter'],

			// strings
			[/"([^"\\]|\\.)*$/, 'string.invalid'],  // non-teminated string
			[/"/, 'string', '@string'],

			// characters
			[/'[^\\']'/, 'string'],
			[/(')(@escapes)(')/, ['string', 'string.escape', 'string']],
			[/'/, 'string.invalid']
		],

		whitespace: [
			[/[ \t\r\n]+/, ''],
			[/\/\*\*(?!\/)/, 'comment.doc', '@javadoc'],
			[/\/\*/, 'comment', '@comment'],
			[/\/\/.*$/, 'comment'],
		],

		comment: [
			[/[^\/*]+/, 'comment'],
			// [/\/\*/, 'comment', '@push' ],    // nested comment not allowed :-(
			// [/\/\*/,    'comment.invalid' ],    // this breaks block comments in the shape of /* //*/
			[/\*\//, 'comment', '@pop'],
			[/[\/*]/, 'comment']
		],
		//Identical copy of comment above, except for the addition of .doc
		javadoc: [
			[/[^\/*]+/, 'comment.doc'],
			// [/\/\*/, 'comment.doc', '@push' ],    // nested comment not allowed :-(
			[/\/\*/, 'comment.doc.invalid'],
			[/\*\//, 'comment.doc', '@pop'],
			[/[\/*]/, 'comment.doc']
		],

		string: [
			[/[^\\"]+/, 'string'],
			[/@escapes/, 'string.escape'],
			[/\\./, 'string.escape.invalid'],
			[/"/, 'string', '@pop']
		],
	},
};
</pre
				>

				<!--******************************************
    Javascript
**********************************************-->
				<pre id="javascript-sample">
// Type source code in JavaScript here...
define('module',[],function()
{
  function test(s) {
    return s.replace(/[a-z$]oo\noo$/, 'bar');
  }

  return {
    main: alert(test("hello monarch world\n"))
  }
});</pre
				>
				<pre id="javascript">
// Difficulty: "Moderate"
// This is the JavaScript tokenizer that is actually used to highlight
// all code in the syntax definition editor and the documentation!
//
// This definition takes special care to highlight regular
// expressions correctly, which is convenient when writing
// syntax highlighter specifications.
return {
	// Set defaultToken to invalid to see what you do not tokenize yet
	defaultToken: 'invalid',
	tokenPostfix: '.js',

	keywords: [
		'break', 'case', 'catch', 'class', 'continue', 'const',
		'constructor', 'debugger', 'default', 'delete', 'do', 'else',
		'export', 'extends', 'false', 'finally', 'for', 'from', 'function',
		'get', 'if', 'import', 'in', 'instanceof', 'let', 'new', 'null',
		'return', 'set', 'super', 'switch', 'symbol', 'this', 'throw', 'true',
		'try', 'typeof', 'undefined', 'var', 'void', 'while', 'with', 'yield',
		'async', 'await', 'of'
	],

	typeKeywords: [
		'any', 'boolean', 'number', 'object', 'string', 'undefined'
	],

	operators: [
		'&lt;=', '&gt;=', '==', '!=', '===', '!==', '=&gt;', '+', '-', '**',
		'*', '/', '%', '++', '--', '&lt;&lt;', '&lt;/', '&gt;&gt;', '&gt;&gt;&gt;', '&amp;',
		'|', '^', '!', '~', '&amp;&amp;', '||', '?', ':', '=', '+=', '-=',
		'*=', '**=', '/=', '%=', '&lt;&lt;=', '&gt;&gt;=', '&gt;&gt;&gt;=', '&amp;=', '|=',
		'^=', '@',
	],

	// we include these common regular expressions
	symbols: /[=&gt;&lt;!~?:&amp;|+\-*\/\^%]+/,
	escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,
	digits: /\d+(_+\d+)*/,
	octaldigits: /[0-7]+(_+[0-7]+)*/,
	binarydigits: /[0-1]+(_+[0-1]+)*/,
	hexdigits: /[[0-9a-fA-F]+(_+[0-9a-fA-F]+)*/,

	regexpctl: /[(){}\[\]\$\^|\-*+?\.]/,
	regexpesc: /\\(?:[bBdDfnrstvwWn0\\\/]|@regexpctl|c[A-Z]|x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4})/,

	// The main tokenizer for our languages
	tokenizer: {
		root: [
			[/[{}]/, 'delimiter.bracket'],
			{ include: 'common' }
		],

		common: [
			// identifiers and keywords
			[/[a-z_$][\w$]*/, {
				cases: {
					'@typeKeywords': 'keyword',
					'@keywords': 'keyword',
					'@default': 'identifier'
				}
			}],
			[/[A-Z][\w\$]*/, 'type.identifier'],  // to show class names nicely
			// [/[A-Z][\w\$]*/, 'identifier'],

			// whitespace
			{ include: '@whitespace' },

			// regular expression: ensure it is terminated before beginning (otherwise it is an opeator)
			[/\/(?=([^\\\/]|\\.)+\/([gimsuy]*)(\s*)(\.|;|\/|,|\)|\]|\}|$))/, { token: 'regexp', bracket: '@open', next: '@regexp' }],

			// delimiters and operators
			[/[()\[\]]/, '@brackets'],
			[/[&lt;&gt;](?!@symbols)/, '@brackets'],
			[/@symbols/, {
				cases: {
					'@operators': 'delimiter',
					'@default': ''
				}
			}],

			// numbers
			[/(@digits)[eE]([\-+]?(@digits))?/, 'number.float'],
			[/(@digits)\.(@digits)([eE][\-+]?(@digits))?/, 'number.float'],
			[/0[xX](@hexdigits)/, 'number.hex'],
			[/0[oO]?(@octaldigits)/, 'number.octal'],
			[/0[bB](@binarydigits)/, 'number.binary'],
			[/(@digits)/, 'number'],

			// delimiter: after number because of .\d floats
			[/[;,.]/, 'delimiter'],

			// strings
			[/"([^"\\]|\\.)*$/, 'string.invalid'],  // non-teminated string
			[/'([^'\\]|\\.)*$/, 'string.invalid'],  // non-teminated string
			[/"/, 'string', '@string_double'],
			[/'/, 'string', '@string_single'],
			[/`/, 'string', '@string_backtick'],
		],

		whitespace: [
			[/[ \t\r\n]+/, ''],
			[/\/\*\*(?!\/)/, 'comment.doc', '@jsdoc'],
			[/\/\*/, 'comment', '@comment'],
			[/\/\/.*$/, 'comment'],
		],

		comment: [
			[/[^\/*]+/, 'comment'],
			[/\*\//, 'comment', '@pop'],
			[/[\/*]/, 'comment']
		],

		jsdoc: [
			[/[^\/*]+/, 'comment.doc'],
			[/\*\//, 'comment.doc', '@pop'],
			[/[\/*]/, 'comment.doc']
		],

		// We match regular expression quite precisely
		regexp: [
			[/(\{)(\d+(?:,\d*)?)(\})/, ['regexp.escape.control', 'regexp.escape.control', 'regexp.escape.control']],
			[/(\[)(\^?)(?=(?:[^\]\\\/]|\\.)+)/, ['regexp.escape.control', { token: 'regexp.escape.control', next: '@regexrange' }]],
			[/(\()(\?:|\?=|\?!)/, ['regexp.escape.control', 'regexp.escape.control']],
			[/[()]/, 'regexp.escape.control'],
			[/@regexpctl/, 'regexp.escape.control'],
			[/[^\\\/]/, 'regexp'],
			[/@regexpesc/, 'regexp.escape'],
			[/\\\./, 'regexp.invalid'],
			[/(\/)([gimsuy]*)/, [{ token: 'regexp', bracket: '@close', next: '@pop' }, 'keyword.other']],
		],

		regexrange: [
			[/-/, 'regexp.escape.control'],
			[/\^/, 'regexp.invalid'],
			[/@regexpesc/, 'regexp.escape'],
			[/[^\]]/, 'regexp'],
			[/\]/, { token: 'regexp.escape.control', next: '@pop', bracket: '@close' }],
		],

		string_double: [
			[/[^\\"]+/, 'string'],
			[/@escapes/, 'string.escape'],
			[/\\./, 'string.escape.invalid'],
			[/"/, 'string', '@pop']
		],

		string_single: [
			[/[^\\']+/, 'string'],
			[/@escapes/, 'string.escape'],
			[/\\./, 'string.escape.invalid'],
			[/'/, 'string', '@pop']
		],

		string_backtick: [
			[/\$\{/, { token: 'delimiter.bracket', next: '@bracketCounting' }],
			[/[^\\`$]+/, 'string'],
			[/@escapes/, 'string.escape'],
			[/\\./, 'string.escape.invalid'],
			[/`/, 'string', '@pop']
		],

		bracketCounting: [
			[/\{/, 'delimiter.bracket', '@bracketCounting'],
			[/\}/, 'delimiter.bracket', '@pop'],
			{ include: 'common' }
		],
	},
};
</pre
				>

				<!--******************************************
    Dafny
**********************************************-->
				<pre id="dafny-sample">
// This method computes the sum and max of a given array of
// integers.  The method's postcondition only promises that
// 'sum' will be no greater than 'max'.  Can you write a
// different method body that also achieves this postcondition?
// Hint: Your program does not have to compute the sum and
// max of the array, despite the suggestive names of the
// out-parameters.
method M(N: int, a: array&lt;int&gt;) returns (sum: int, max: int)
  requires 0 &lt;= N &amp; a != null &amp; a.Length == N;
  ensures sum &lt;= N * max;
{
  sum := 0;
  max := 0;
  var i := 0;
  while (i &lt; N)
    invariant i &lt;= N &amp; sum &lt;= i * max;
  {
    if (max &lt; a[i]) {
      max := a[i];
    }
    sum := sum + a[i];
    i := i + 1;
  }
}
</pre
				>
				<pre id="dafny">
// Difficulty: "Easy"
// Language definition sample for the Dafny language.
// See 'http://rise4fun.com/Dafny'.
return {
  keywords: [
    'class','datatype','codatatype','type','function',
    'ghost','var','method','constructor',
    'module','import','default','as','opened','static','refines',
    'returns','break','then','else','if','label','return','while','print','where',
    'new','parallel', 'in','this','fresh','choose',
    'match','case','assert','assume', 'predicate','copredicate',
    'forall','exists', 'false','true','null','old',
    'calc','iterator','yields','yield'
  ],

  verifyKeywords: [
    'requires','ensures','modifies','reads','free', 'invariant','decreases',
  ],

  types: [
    'bool','multiset','map','nat','int','object','set','seq', 'array'
  ],

  brackets: [
    ['{','}','delimiter.curly'],
    ['[',']','delimiter.square'],
    ['(',')','delimiter.parenthesis']
  ],

  // Dafny uses C# style strings
  escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,

  tokenizer: {
    root: [
      // identifiers
      [/array([2-9]\d*|1\d+)/, 'type.keyword' ],
      [/[a-zA-Z'_\?\\][\w'\?\\]*/, { cases: {'@keywords': 'keyword',
                                             '@verifyKeywords': 'constructor.identifier',
                                             '@types'   : 'type.keyword',
                                             '@default' : 'identifier' }}],
      [':=','keyword'],

      // whitespace
      { include: '@whitespace' },

      [/[{}()\[\]]/, '@brackets'],
      [/[;,]/, 'delimiter'],

      // literals
      [/[0-9]+/, 'number'],

      // strings
      [/"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/"/,  'string', '@string' ],
    ],

    whitespace: [
      [/[ \t\r\n]+/, 'white'],
      [/\/\*/,       'comment', '@comment' ],
      [/\/\/.*$/,    'comment'],
    ],

    comment: [
      [/[^\/*]+/, 'comment' ],
      [/\/\*/, 'comment', '@push' ],    // nested comment
      ["\\*/",    'comment', '@pop'  ],
      [/[\/*]/,   'comment' ]
    ],

    string: [
      [/[^\\"]+/,  'string'],
      [/@escapes/, 'string.escape'],
      [/\\./,      'string.escape.invalid'],
      [/"/,        'string', '@pop' ]
    ],
  }
};</pre
				>

				<!--******************************************
    Koka
**********************************************-->
				<pre id="koka-sample">
// This module implements the Garcia-Wachs algorithm.
// It is an adaptation of the algorithm in ML as described by Jean-Christophe Filliï¿½tre:
// in ''A functional implementation of the Garsia-Wachs algorithm. (functional pearl). ML workshop 2008, pages 91--96''.
// See: http://www.lri.fr/~filliatr/publis/gw-wml08.pdf
//
// The algorithm is interesting since it uses mutable references shared between a list and tree but the
// side-effects are not observable from outside. Koka automatically infers that final algorithm is pure.
module garcia-wachs

//----------------------------------------------------
// Trees
//----------------------------------------------------
public type tree&lt;a> {
  con Leaf(value :a)
  con Node(left :tree&lt;a>, right :tree&lt;a>)
}

fun show( t : tree&lt;char> ) : string
{
  match(t) {
    Leaf(c) -> Core.show(c)
    Node(l,r) -> "Node(" + show(l) + "," + show(r) + ")"
  }
}


//----------------------------------------------------
// Non empty lists
//----------------------------------------------------
public type list1&lt;a> {
  Cons1( head : a, tail : list&lt;a> )
}


fun map( xs, f ) {
  val Cons1(y,ys) = xs
  return Cons1(f(y), Core.map(ys,f))
}

fun zip( xs :list1&lt;a>, ys :list1&lt;b> ) : list1&lt;(a,b)> {
  Cons1( (xs.head, ys.head), Core.zip(xs.tail, ys.tail))
}


//----------------------------------------------------
// Phase 1
// note: koka cannot yet prove that the mutual recursive
// functions "insert" and "extract" always terminate :-(
//----------------------------------------------------

fun insert( after : list&lt;(tree&lt;a>,int)>, t : (tree&lt;a>,int), before : list&lt;(tree&lt;a>,int)> ) : div tree&lt;a>
{
  match(before) {
    Nil -> extract( [], Cons1(t,after) )
    Cons(x,xs) -> {
      if (x.snd &lt; t.snd) then return insert( Cons(x,after), t, xs )
      match(xs) {
        Nil        -> extract( [], Cons1(x,Cons(t,after)) )
        Cons(y,ys) -> extract( ys, Cons1(y,Cons(x,Cons(t,after))) )
      }
    }
  }
}

fun extract( before : list&lt;(tree&lt;a>,int)>, after : list1&lt;(tree&lt;a>,int)> ) : div tree&lt;a>
{
  val Cons1((t1,w1) as x, xs ) = after
  match(xs) {
    Nil -> t1
    Cons((t2,w2) as y, ys) -> match(ys) {
      Nil -> insert( [], (Node(t1,t2), w1+w2), before )
      Cons((_,w3),_zs) ->
        if (w1 &lt;= w3)
         then insert(ys, (Node(t1,t2), w1+w2), before)
         else extract(Cons(x,before), Cons1(y,ys))
    }
  }
}


fun balance( xs : list1&lt;(tree&lt;a>,int)> ) : div tree&lt;a>
{
  extract( [], xs )
}

fun mark( depth :int, t :tree&lt;(a,ref&lt;h,int>)> ) : &lt;write&lt;h>> ()
{
  match(t) {
    Leaf((_,d)) -> d := depth
    Node(l,r)   -> { mark(depth+1,l); mark(depth+1,r) }
  }
}


fun build( depth :int, xs :list1&lt;(a,ref&lt;h,int>)> ) : &lt;read&lt;h>,div> (tree&lt;a>,list&lt;(a,ref&lt;h,int>)>)
{
  if (!xs.head.snd == depth) return (Leaf(xs.head.fst), xs.tail)

  l = build(depth+1, xs)
  match(l.snd) {
    Nil -> (l.fst, Nil)
    Cons(y,ys) -> {
      r = build(depth+1, Cons1(y,ys))
      (Node(l.fst,r.fst), r.snd)
    }
  }
}

public function garciawachs( xs : list1&lt;(a,int)> ) : div tree&lt;a>
{
  refs   = xs.map(fst).map( fun(x) { (x, ref(0)) } )
  wleafs = zip( refs.map(Leaf), xs.map(snd) )

  tree = balance(wleafs)
  mark(0,tree)
  build(0,refs).fst
}

public function main() {
  wlist = Cons1(('a',3), [('b',2),('c',1),('d',4),('e',5)])
  tree  = wlist.garciawachs()
  tree.show.print()
}
</pre
				>
				<pre id="koka">
// Difficulty: "Moderate"
// Language definition for the Koka language
// See 'rise4fun.com/Koka' for more information.
// This definition uses states extensively to color types correctly
// where it matches up brackets inside nested types.
return {
  keywords: [
    'infix', 'infixr', 'infixl', 'prefix', 'postfix',
    'type', 'cotype', 'rectype', 'alias', 'struct', 'enum', 'con',
    'fun', 'function', 'val', 'var', 'external',
    'if', 'then', 'else', 'elif', 'return', 'match',
    'forall', 'exists', 'some', 'with',
    'private', 'public', 'private',
    'module', 'import', 'as',
    '=', '.', ':', ':=', '-&gt;',
    'include', 'inline','rec','try', 'yield',
    'interface', 'instance'
  ],

  builtins: [
    'for', 'while', 'repeat',
    'foreach', 'foreach-indexed',
    'error', 'catch', 'finally',
    'cs', 'js', 'file', 'ref', 'assigned'
  ],

  typeKeywords: [
    'forall', 'exists', 'some', 'with'
  ],

  typeStart: [
    'type','cotype','rectype','alias','struct','enum'
  ],

  moduleKeywords: [
    'module','import','as'
  ],

  kindConstants: [
    'E','P','H','V','X'
  ],

  escapes :  /\\(?:[nrt\\"'\?]|x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4}|U[0-9a-fA-F]{6})/,
  symbols0: /[\$%&amp;\*\+@!\/\\\^~=\.:\-\?]/,
  symbols : /(?:@symbols0|[\|&lt;&gt;])+/,
  idchars : /(?:\w|\-[a-zA-Z])*/,

  tokenizer: {
    root: [
      // identifiers and operators
      [/[a-z]@idchars/,
        { cases:{ '@keywords': {
                    cases: { 'alias'  : { token: 'keyword', next: '@alias_type' },
                             'struct' : { token: 'keyword', next: '@struct_type' },
                             'type|cotype|rectype': { token: 'keyword', next: '@type' },
                             'module|as|import': { token: 'keyword', next: '@module' },
                             '@default': 'keyword' }
                  },
                  '@builtins': 'identifier.predefined',
                  '@default' : 'identifier' }
        }
      ],

      [/([A-Z]@idchars)(\.?)/,
        { cases: { '$2': ['identifier.namespace','keyword.dot'],
                   '@default': 'identifier.constructor' }}
      ],

      [/_@idchars/, 'identifier.wildcard'],


      // whitespace
      { include: '@whitespace' },

      [/[{}()\[\]]/, '@brackets'],
      [/[;,`]/, 'delimiter'],

      // do not scan these as operators
      [/[&lt;&gt;](?![&lt;&gt;|]*@symbols0)/, '@brackets' ],
      [/-&gt;(?!@symbols0|[&gt;\|])/, 'keyword' ],
      [/::?(?!@symbols0)/, 'type.operator', '@type'],
      [/::?(?=\?)/, 'type.operator', '@type'],

      // literal string
      [/@"/, { token: 'string.quote', bracket: '@open', next: '@litstring' } ],

      // operators
      [/@symbols/, { cases: { '\\-': 'operator.minus',
                              '@keywords': 'keyword.operator',
                              '@default': 'operator' }}
      ],

      // numbers
      [/[0-9]+\.[0-9]+([eE][\-+]?[0-9]+)?/, 'number.float'],
      [/0[xX][0-9a-fA-F]+/, 'number.hex'],
      [/[0-9]+/, 'number'],

      // strings
      [/"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/"/,  { token: 'string.quote', bracket: '@open', next: '@string' } ],

      // characters
      [/'[^\\']'/, 'string'],
      [/(')(@escapes)(')/, ['string','string.escape','string']],
      [/'/, 'string.invalid'],

      // meta
      [/^[ ]*#.*/, 'namespace']
    ],

    whitespace: [
      [/[ \r\n]+/, 'white'],
      ['/\\*', 'comment', '@comment' ],
      ['//$',  'comment'],
      ['//',   'comment', '@line_comment']
    ],

    comment: [
      [/^\s*["|]\s*$/, 'comment', '@comment_docblock'],
      [/[^\/*"|]+/, 'comment' ],
      ['/\\*',  'comment', '@push' ],
      ['\\*/',  'comment', '@pop'  ],
      [/(")((?:[^"]|"")*)(")/, ['comment','comment.doc','comment']],
      [/(\|)((?:[^|]|\|\|)*)(\|)/, ['comment','comment.doc','comment']],
      [/[\/*"|]/, 'comment']
    ],

    comment_docblock: [
      [/\*\/|\/\*/,  '@rematch', '@pop'], // recover: back to comment mode
      [/^\s*"\s*$/,  'comment', '@pop'],
      [/^\s*\|\s*$/, 'comment', '@pop'],
      [/[^*\/]+/, 'comment.doc'],
      [/./, 'comment.doc'] // catch all
    ],

    line_comment: [
      [/[^"|]*$/, 'comment', '@pop' ],
      [/[^"|]+/,  'comment' ],
      [/(")((?:[^"]|"")*)(")/,
        ['comment','comment.doc', { cases: { '@eos':  { token: 'comment', next: '@pop' },
                                             '@default': 'comment' }}]
      ],
      [/(\|)((?:[^|]|\|\|)*)(\|)/,
        ['comment','comment.doc', { cases: { '@eos':  { token: 'comment', next: '@pop' },
                                             '@default': 'comment' }}]
      ],
      [/.*$/, 'comment', '@pop'] // catch all
    ],

    string: [
      [/[^\\"]+/,  'string'],
      [/@escapes/, 'string.escape'],
      [/\\./,      'string.escape.invalid'],
      [/"/,        { token: 'string.quote', bracket: '@close', next: '@pop' } ]
    ],

    litstring: [
      [/[^"]+/,    'string'],
      [/""/,       'string.escape'],
      [/"/,        { token: 'string.quote', bracket: '@close', next: '@pop' } ]
    ],

    // Module mode: color names as module names
    module: [
      { include: '@whitespace' },
      [/[a-z]@idchars/,
        { cases: { '@moduleKeywords': 'keyword',
                   '@keywords': { token: '@rematch', next: '@pop' },
                   '@default': 'identifier.namespace' }}
      ],
      [/[A-Z]@idchars/, 'identifier.namespace'],
      [/\.(?!@symbols)/, 'keyword.operator.dot'],
      ['','','@pop'] // catch all
    ],

    // Koka type coloring is a bit involved but looks cool :-)
    alias_type: [
      ['=', 'keyword.operator'],                // allow equal sign
      { include: '@type' }
    ],

    struct_type: [
      [ /\((?!,*\))/, '@brackets', '@pop'],    // allow for tuple struct definition
      { include: '@type' }
    ],

    type: [
      [ /[(\[&lt;]/, { token: '@brackets.type' }, '@type_nested'],
      { include: '@type_content' }
    ],

    type_nested: [
      [/[)\]&gt;]/, { token: '@brackets.type' }, '@pop' ],
      [/[(\[&lt;]/, { token: '@brackets.type' }, '@push'],
      [/,/, 'delimiter.type'],
      [/([a-z]@idchars)(\s*)(:)(?!:)/,['type.identifier.typeparam','white','type.operator']],
      { include: '@type_content' }
    ],

    type_content: [
      { include: '@whitespace' },

      // type identifiers
      [/[*!](?!@symbols)/, 'type.kind.identifier'],
      [/[a-z][0-9]*(?![a-zA-Z_\-])/, 'type.identifier.typevar'],
      [/_@idchars/, 'type.identifier.typevar'],
      [/[a-z]@idchars/,
        { cases: { '@typeKeywords': 'type.keyword',
                   '@keywords': { token: '@rematch', next: '@pop' },
                   '@builtins': 'type.predefined',
                   '@default': 'type.identifier'
        }}
      ],
      [/[A-Z]@idchars(\.?)/,
        { cases: { '$2': ['identifier.namespace','keyword.dot'],
                   '@kindConstants': 'type.kind.identifier',
                   '@default': 'type.identifier'
        }}
      ],

      [/::|-&gt;|[\.:|]/, 'type.operator'],
      ['','','@pop']  // catch all
    ]
  }
};
</pre
				>

				<!--******************************************
    HTML
**********************************************-->
				<pre id="html-sample">
&lt;!DOCTYPE html>
&lt;html>
&lt;head>
  &lt;title>Monarch Workbench&lt;/title>

  &lt;meta http-equiv="X-UA-Compatible" content="IE=edge" />
  &lt;!-- a comment
  -->
  &lt;style>
    body { font-family: Consolas; } /* nice */
  &lt;/style>
&lt;/head>
&lt;body>
  &lt;div class="test">
    &lt;script>
      function() {
        alert("hi &lt;/script>"); // javascript
      };
    &lt;/script>
    &lt;script type="text/x-dafny">
      class Foo {
        x : int;
        invariant x > 0;
      };
    &lt;/script>
  &lt;/div>
&lt;/body>
&lt;/html>
</pre
				>
				<pre id="html">
// Difficulty: "Hurt me plenty"
// Language definition for HTML
// This definition uses states extensively to
// - match up tags.
// - and to embed scripts dynamically
// See also the documentation for an explanation of these techniques
return {
	defaultToken: '',
	tokenPostfix: '.html',
	ignoreCase: true,

	// The main tokenizer for our languages
	tokenizer: {
		root: [
			[/&lt;!DOCTYPE/, 'metatag', '@doctype'],
			[/&lt;!--/, 'comment', '@comment'],
			[/(&lt;)((?:[\w\-]+:)?[\w\-]+)(\s*)(\/&gt;)/, ['delimiter', 'tag', '', 'delimiter']],
			[/(&lt;)(script)/, ['delimiter', { token: 'tag', next: '@script' }]],
			[/(&lt;)(style)/, ['delimiter', { token: 'tag', next: '@style' }]],
			[/(&lt;)((?:[\w\-]+:)?[\w\-]+)/, ['delimiter', { token: 'tag', next: '@otherTag' }]],
			[/(&lt;\/)((?:[\w\-]+:)?[\w\-]+)/, ['delimiter', { token: 'tag', next: '@otherTag' }]],
			[/&lt;/, 'delimiter'],
			[/[^&lt;]+/], // text
		],

		doctype: [
			[/[^&gt;]+/, 'metatag.content'],
			[/&gt;/, 'metatag', '@pop'],
		],

		comment: [
			[/--&gt;/, 'comment', '@pop'],
			[/[^-]+/, 'comment.content'],
			[/./, 'comment.content']
		],

		otherTag: [
			[/\/?&gt;/, 'delimiter', '@pop'],
			[/"([^"]*)"/, 'attribute.value'],
			[/'([^']*)'/, 'attribute.value'],
			[/[\w\-]+/, 'attribute.name'],
			[/=/, 'delimiter'],
			[/[ \t\r\n]+/], // whitespace
		],

		// -- BEGIN &lt;script&gt; tags handling

		// After &lt;script
		script: [
			[/type/, 'attribute.name', '@scriptAfterType'],
			[/"([^"]*)"/, 'attribute.value'],
			[/'([^']*)'/, 'attribute.value'],
			[/[\w\-]+/, 'attribute.name'],
			[/=/, 'delimiter'],
			[/&gt;/, { token: 'delimiter', next: '@scriptEmbedded', nextEmbedded: 'text/javascript' }],
			[/[ \t\r\n]+/], // whitespace
			[/(&lt;\/)(script\s*)(&gt;)/, ['delimiter', 'tag', { token: 'delimiter', next: '@pop' }]]
		],

		// After &lt;script ... type
		scriptAfterType: [
			[/=/, 'delimiter', '@scriptAfterTypeEquals'],
			[/&gt;/, { token: 'delimiter', next: '@scriptEmbedded', nextEmbedded: 'text/javascript' }], // cover invalid e.g. &lt;script type&gt;
			[/[ \t\r\n]+/], // whitespace
			[/&lt;\/script\s*&gt;/, { token: '@rematch', next: '@pop' }]
		],

		// After &lt;script ... type =
		scriptAfterTypeEquals: [
			[/"([^"]*)"/, { token: 'attribute.value', switchTo: '@scriptWithCustomType.$1' }],
			[/'([^']*)'/, { token: 'attribute.value', switchTo: '@scriptWithCustomType.$1' }],
			[/&gt;/, { token: 'delimiter', next: '@scriptEmbedded', nextEmbedded: 'text/javascript' }], // cover invalid e.g. &lt;script type=&gt;
			[/[ \t\r\n]+/], // whitespace
			[/&lt;\/script\s*&gt;/, { token: '@rematch', next: '@pop' }]
		],

		// After &lt;script ... type = $S2
		scriptWithCustomType: [
			[/&gt;/, { token: 'delimiter', next: '@scriptEmbedded.$S2', nextEmbedded: '$S2' }],
			[/"([^"]*)"/, 'attribute.value'],
			[/'([^']*)'/, 'attribute.value'],
			[/[\w\-]+/, 'attribute.name'],
			[/=/, 'delimiter'],
			[/[ \t\r\n]+/], // whitespace
			[/&lt;\/script\s*&gt;/, { token: '@rematch', next: '@pop' }]
		],

		scriptEmbedded: [
			[/&lt;\/script/, { token: '@rematch', next: '@pop', nextEmbedded: '@pop' }],
			[/[^&lt;]+/, '']
		],

		// -- END &lt;script&gt; tags handling


		// -- BEGIN &lt;style&gt; tags handling

		// After &lt;style
		style: [
			[/type/, 'attribute.name', '@styleAfterType'],
			[/"([^"]*)"/, 'attribute.value'],
			[/'([^']*)'/, 'attribute.value'],
			[/[\w\-]+/, 'attribute.name'],
			[/=/, 'delimiter'],
			[/&gt;/, { token: 'delimiter', next: '@styleEmbedded', nextEmbedded: 'text/css' }],
			[/[ \t\r\n]+/], // whitespace
			[/(&lt;\/)(style\s*)(&gt;)/, ['delimiter', 'tag', { token: 'delimiter', next: '@pop' }]]
		],

		// After &lt;style ... type
		styleAfterType: [
			[/=/, 'delimiter', '@styleAfterTypeEquals'],
			[/&gt;/, { token: 'delimiter', next: '@styleEmbedded', nextEmbedded: 'text/css' }], // cover invalid e.g. &lt;style type&gt;
			[/[ \t\r\n]+/], // whitespace
			[/&lt;\/style\s*&gt;/, { token: '@rematch', next: '@pop' }]
		],

		// After &lt;style ... type =
		styleAfterTypeEquals: [
			[/"([^"]*)"/, { token: 'attribute.value', switchTo: '@styleWithCustomType.$1' }],
			[/'([^']*)'/, { token: 'attribute.value', switchTo: '@styleWithCustomType.$1' }],
			[/&gt;/, { token: 'delimiter', next: '@styleEmbedded', nextEmbedded: 'text/css' }], // cover invalid e.g. &lt;style type=&gt;
			[/[ \t\r\n]+/], // whitespace
			[/&lt;\/style\s*&gt;/, { token: '@rematch', next: '@pop' }]
		],

		// After &lt;style ... type = $S2
		styleWithCustomType: [
			[/&gt;/, { token: 'delimiter', next: '@styleEmbedded.$S2', nextEmbedded: '$S2' }],
			[/"([^"]*)"/, 'attribute.value'],
			[/'([^']*)'/, 'attribute.value'],
			[/[\w\-]+/, 'attribute.name'],
			[/=/, 'delimiter'],
			[/[ \t\r\n]+/], // whitespace
			[/&lt;\/style\s*&gt;/, { token: '@rematch', next: '@pop' }]
		],

		styleEmbedded: [
			[/&lt;\/style/, { token: '@rematch', next: '@pop', nextEmbedded: '@pop' }],
			[/[^&lt;]+/, '']
		],

		// -- END &lt;style&gt; tags handling
	},
};
</pre
				>

				<!--******************************************
    Markdown
**********************************************-->
				<pre id="markdown-sample">
# Header 1 #
## Header 2 ##
### Header 3 ###             (Hashes on right are optional)
## Markdown plus h2 with a custom ID ##   {#id-goes-here}
[Link back to H2](#id-goes-here)

&lt;!-- html madness -->
&lt;div class="custom-class" markdown="1">
  &lt;div>
    nested div
  &lt;/div>
  &lt;script type='text/x-koka'>
    function( x: int ) { return x*x; }
  &lt;/script>
  This is a div _with_ underscores
  and a &amp; &lt;b class="bold">bold&lt;/b> element.
  &lt;style>
    body { font: "Consolas" }
  &lt;/style>
&lt;/div>

* Bullet lists are easy too
- Another one
+ Another one

This is a paragraph, which is text surrounded by
whitespace. Paragraphs can be on one
line (or many), and can drone on for hours.

Now some inline markup like _italics_,  **bold**,
and `code()`. Note that underscores
in_words_are ignored.


````dafny
  method Foo() {
    requires "github style code blocks"
  }
````

````application/json
  { value: ["or with a mime type"] }
````

> Blockquotes are like quoted text in email replies
>> And, they can be nested

1. A numbered list
2. Which is numbered
3. With periods and a space

And now some code:

    // Code is just text indented a bit
    which(is_easy) to_remember();

And a block

~~~
// Markdown extra adds un-indented code blocks too

if (this_is_more_code == true &amp;&amp; !indented) {
    // tild wrapped code blocks, also not indented
}
~~~

Text with
two trailing spaces
(on the right)
can be used
for things like poems

### Horizontal rules

* * * *
****
--------------------------

![picture alt](/images/photo.jpeg "Title is optional")

## Markdown plus tables ##

| Header | Header | Right  |
| ------ | ------ | -----: |
|  Cell  |  Cell  |   $10  |
|  Cell  |  Cell  |   $20  |

* Outer pipes on tables are optional
* Colon used for alignment (right versus left)

## Markdown plus definition lists ##

Bottled water
: $ 1.25
: $ 1.55 (Large)

Milk
Pop
: $ 1.75

* Multiple definitions and terms are possible
* Definitions can include multiple paragraphs too

*[ABBR]: Markdown plus abbreviations (produces an &lt;abbr> tag)
</pre
				>

				<pre id="markdown">
// Difficulty: "Ultra-Violence"
// Language definition for Markdown
// Quite complex definition mostly due to almost full inclusion
// of the HTML mode (so we can properly match nested HTML tag definitions)
return {
	defaultToken: '',
	tokenPostfix: '.md',

	// escape codes
	control: /[\\`*_\[\]{}()#+\-\.!]/,
	noncontrol: /[^\\`*_\[\]{}()#+\-\.!]/,
	escapes: /\\(?:@control)/,

	// escape codes for javascript/CSS strings
	jsescapes: /\\(?:[btnfr\\"']|[0-7][0-7]?|[0-3][0-7]{2})/,

	// non matched elements
	empty: [
		'area', 'base', 'basefont', 'br', 'col', 'frame',
		'hr', 'img', 'input', 'isindex', 'link', 'meta', 'param'
	],

	tokenizer: {
		root: [

			// headers (with #)
			[/^(\s{0,3})(#+)((?:[^\\#]|@escapes)+)((?:#+)?)/, ['white', 'keyword', 'keyword', 'keyword']],

			// headers (with =)
			[/^\s*(=+|\-+)\s*$/, 'keyword'],

			// headers (with ***)
			[/^\s*((\*[ ]?)+)\s*$/, 'meta.separator'],

			// quote
			[/^\s*&gt;+/, 'comment'],

			// list (starting with * or number)
			[/^\s*([\*\-+:]|\d+\.)\s/, 'keyword'],

			// code block (4 spaces indent)
			[/^(\t|[ ]{4})[^ ].*$/, 'string'],

			// code block (3 tilde)
			[/^\s*~~~\s*((?:\w|[\/\-#])+)?\s*$/, { token: 'string', next: '@codeblock' }],

			// github style code blocks (with backticks and language)
			[/^\s*```\s*((?:\w|[\/\-#])+)\s*$/, { token: 'string', next: '@codeblockgh', nextEmbedded: '$1' }],

			// github style code blocks (with backticks but no language)
			[/^\s*```\s*$/, { token: 'string', next: '@codeblock' }],

			// markup within lines
			{ include: '@linecontent' },
		],

		codeblock: [
			[/^\s*~~~\s*$/, { token: 'string', next: '@pop' }],
			[/^\s*```\s*$/, { token: 'string', next: '@pop' }],
			[/.*$/, 'variable.source'],
		],

		// github style code blocks
		codeblockgh: [
			[/```\s*$/, { token: 'variable.source', next: '@pop', nextEmbedded: '@pop' }],
			[/[^`]+/, 'variable.source'],
		],

		linecontent: [

			// escapes
			[/&amp;\w+;/, 'string.escape'],
			[/@escapes/, 'escape'],

			// various markup
			[/\b__([^\\_]|@escapes|_(?!_))+__\b/, 'strong'],
			[/\*\*([^\\*]|@escapes|\*(?!\*))+\*\*/, 'strong'],
			[/\b_[^_]+_\b/, 'emphasis'],
			[/\*([^\\*]|@escapes)+\*/, 'emphasis'],
			[/`([^\\`]|@escapes)+`/, 'variable'],

			// links
			[/\{+[^}]+\}+/, 'string.target'],
			[/(!?\[)((?:[^\]\\]|@escapes)*)(\]\([^\)]+\))/, ['string.link', '', 'string.link']],
			[/(!?\[)((?:[^\]\\]|@escapes)*)(\])/, 'string.link'],

			// or html
			{ include: 'html' },
		],

		// Note: it is tempting to rather switch to the real HTML mode instead of building our own here
		// but currently there is a limitation in Monarch that prevents us from doing it: The opening
		// '&lt;' would start the HTML mode, however there is no way to jump 1 character back to let the
		// HTML mode also tokenize the opening angle bracket. Thus, even though we could jump to HTML,
		// we cannot correctly tokenize it in that mode yet.
		html: [
			// html tags
			[/&lt;(\w+)\/&gt;/, 'tag'],
			[/&lt;(\w+)/, {
				cases: {
					'@empty': { token: 'tag', next: '@tag.$1' },
					'@default': { token: 'tag', next: '@tag.$1' }
				}
			}],
			[/&lt;\/(\w+)\s*&gt;/, { token: 'tag' }],

			[/&lt;!--/, 'comment', '@comment']
		],

		comment: [
			[/[^&lt;\-]+/, 'comment.content'],
			[/--&gt;/, 'comment', '@pop'],
			[/&lt;!--/, 'comment.content.invalid'],
			[/[&lt;\-]/, 'comment.content']
		],

		// Almost full HTML tag matching, complete with embedded scripts &amp; styles
		tag: [
			[/[ \t\r\n]+/, 'white'],
			[/(type)(\s*=\s*)(")([^"]+)(")/, ['attribute.name.html', 'delimiter.html', 'string.html',
				{ token: 'string.html', switchTo: '@tag.$S2.$4' },
				'string.html']],
			[/(type)(\s*=\s*)(')([^']+)(')/, ['attribute.name.html', 'delimiter.html', 'string.html',
				{ token: 'string.html', switchTo: '@tag.$S2.$4' },
				'string.html']],
			[/(\w+)(\s*=\s*)("[^"]*"|'[^']*')/, ['attribute.name.html', 'delimiter.html', 'string.html']],
			[/\w+/, 'attribute.name.html'],
			[/\/&gt;/, 'tag', '@pop'],
			[/&gt;/, {
				cases: {
					'$S2==style': { token: 'tag', switchTo: 'embeddedStyle', nextEmbedded: 'text/css' },
					'$S2==script': {
						cases: {
							'$S3': { token: 'tag', switchTo: 'embeddedScript', nextEmbedded: '$S3' },
							'@default': { token: 'tag', switchTo: 'embeddedScript', nextEmbedded: 'text/javascript' }
						}
					},
					'@default': { token: 'tag', next: '@pop' }
				}
			}],
		],

		embeddedStyle: [
			[/[^&lt;]+/, ''],
			[/&lt;\/style\s*&gt;/, { token: '@rematch', next: '@pop', nextEmbedded: '@pop' }],
			[/&lt;/, '']
		],

		embeddedScript: [
			[/[^&lt;]+/, ''],
			[/&lt;\/script\s*&gt;/, { token: '@rematch', next: '@pop', nextEmbedded: '@pop' }],
			[/&lt;/, '']
		],
	}
};
</pre
				>

				<pre id="ruby-sample">
#
# This program evaluates polynomials.  It first asks for the coefficients
# of a polynomial, which must be entered on one line, highest-order first.
# It then requests values of x and will compute the value of the poly for
# each x.  It will repeatly ask for x values, unless you the user enters
# a blank line.  It that case, it will ask for another polynomial.  If the
# user types quit for either input, the program immediately exits.
#

#
# Function to evaluate a polynomial at x.  The polynomial is given
# as a list of coefficients, from the greatest to the least.
def polyval(x, coef)
    sum = 0
    coef = coef.clone           # Don't want to destroy the original
    while true
        sum += coef.shift       # Add and remove the next coef
        break if coef.empty?    # If no more, done entirely.
        sum *= x                # This happens the right number of times.
    end
    return sum
end

#
# Function to read a line containing a list of integers and return
# them as an array of integers.  If the string conversion fails, it
# throws TypeError.  If the input line is the word 'quit', then it
# converts it to an end-of-file exception
def readints(prompt)
    # Read a line
    print prompt
    line = readline.chomp
    raise EOFError.new if line == 'quit' # You can also use a real EOF.

    # Go through each item on the line, converting each one and adding it
    # to retval.
    retval = [ ]
    for str in line.split(/\s+/)
        if str =~ /^\-?\d+$/
            retval.push(str.to_i)
        else
            raise TypeError.new
        end
    end

    return retval
end

#
# Take a coeff and an exponent and return the string representation, ignoring
# the sign of the coefficient.
def term_to_str(coef, exp)
    ret = ""

    # Show coeff, unless it's 1 or at the right
    coef = coef.abs
    ret = coef.to_s     unless coef == 1 &amp;&amp; exp > 0
    ret += "x" if exp > 0                               # x if exponent not 0
    ret += "^" + exp.to_s if exp > 1                    # ^exponent, if > 1.

    return ret
end

#
# Create a string of the polynomial in sort-of-readable form.
def polystr(p)
    # Get the exponent of first coefficient, plus 1.
    exp = p.length

    # Assign exponents to each term, making pairs of coeff and exponent,
    # Then get rid of the zero terms.
    p = (p.map { |c| exp -= 1; [ c, exp ] }).select { |p| p[0] != 0 }

    # If there's nothing left, it's a zero
    return "0" if p.empty?

    # *** Now p is a non-empty list of [ coef, exponent ] pairs. ***

    # Convert the first term, preceded by a "-" if it's negative.
    result = (if p[0][0] &lt; 0 then "-" else "" end) + term_to_str(*p[0])

    # Convert the rest of the terms, in each case adding the appropriate
    # + or - separating them.
    for term in p[1...p.length]
        # Add the separator then the rep. of the term.
        result += (if term[0] &lt; 0 then " - " else " + " end) +
                term_to_str(*term)
    end

    return result
end

#
# Run until some kind of endfile.
begin
    # Repeat until an exception or quit gets us out.
    while true
        # Read a poly until it works.  An EOF will except out of the
        # program.
        print "\n"
        begin
            poly = readints("Enter a polynomial coefficients: ")
        rescue TypeError
            print "Try again.\n"
            retry
        end
        break if poly.empty?

        # Read and evaluate x values until the user types a blank line.
        # Again, an EOF will except out of the pgm.
        while true
            # Request an integer.
            print "Enter x value or blank line: "
            x = readline.chomp
            break if x == ''
            raise EOFError.new if x == 'quit'

            # If it looks bad, let's try again.
            if x !~ /^\-?\d+$/
                print "That doesn't look like an integer.  Please try again.\n"
                next
            end

            # Convert to an integer and print the result.
            x = x.to_i
            print "p(x) = ", polystr(poly), "\n"
            print "p(", x, ") = ", polyval(x, poly), "\n"
        end
    end
rescue EOFError
    print "\n=== EOF ===\n"
rescue Interrupt, SignalException
    print "\n=== Interrupted ===\n"
else
    print "--- Bye ---\n"
end
</pre
				>
				<pre id="ruby">
// Difficulty: "Nightmare!"
/*
Ruby language definition

Quite a complex language due to elaborate escape sequences
and quoting of literate strings/regular expressions, and
an 'end' keyword that does not always apply to modifiers like until and while,
and a 'do' keyword that sometimes starts a block, but sometimes is part of
another statement (like 'while').

(1) end blocks:
'end' may end declarations like if or until, but sometimes 'if' or 'until'
are modifiers where there is no 'end'. Also, 'do' sometimes starts a block
that is ended by 'end', but sometimes it is part of a 'while', 'for', or 'until'
To do proper brace matching we do some elaborate state manipulation.
some examples:

  until bla do
    work until tired
    list.each do
      foo if test
    end
  end

or

if test
 foo (if test then x end)
 bar if bla
end

or, how about using class as a property..

class Foo
  def endpoint
    self.class.endpoint || routes
  end
end

(2) quoting:
there are many kinds of strings and escape sequences. But also, one can
start many string-like things as '%qx' where q specifies the kind of string
(like a command, escape expanded, regular expression, symbol etc.), and x is
some character and only another 'x' ends the sequence. Except for brackets
where the closing bracket ends the sequence.. and except for a nested bracket
inside the string like entity. Also, such strings can contain interpolated
ruby expressions again (and span multiple lines). Moreover, expanded
regular expression can also contain comments.
*/
return {
	tokenPostfix: '.ruby',

	keywords: [
		'__LINE__', '__ENCODING__', '__FILE__', 'BEGIN', 'END', 'alias', 'and', 'begin',
		'break', 'case', 'class', 'def', 'defined?', 'do', 'else', 'elsif', 'end',
		'ensure', 'for', 'false', 'if', 'in', 'module', 'next', 'nil', 'not', 'or', 'redo',
		'rescue', 'retry', 'return', 'self', 'super', 'then', 'true', 'undef', 'unless',
		'until', 'when', 'while', 'yield',
	],

	keywordops: [
		'::', '..', '...', '?', ':', '=&gt;'
	],

	builtins: [
		'require', 'public', 'private', 'include', 'extend', 'attr_reader',
		'protected', 'private_class_method', 'protected_class_method', 'new'
	],

	// these are closed by 'end' (if, while and until are handled separately)
	declarations: [
		'module', 'class', 'def', 'case', 'do', 'begin', 'for', 'if', 'while', 'until', 'unless'
	],

	linedecls: [
		'def', 'case', 'do', 'begin', 'for', 'if', 'while', 'until', 'unless'
	],

	operators: [
		'^', '&amp;', '|', '&lt;=&gt;', '==', '===', '!~', '=~', '&gt;', '&gt;=', '&lt;', '&lt;=', '&lt;&lt;', '&gt;&gt;', '+',
		'-', '*', '/', '%', '**', '~', '+@', '-@', '[]', '[]=', '`',
		'+=', '-=', '*=', '**=', '/=', '^=', '%=', '&lt;&lt;=', '&gt;&gt;=', '&amp;=', '&amp;&amp;=', '||=', '|='
	],

	brackets: [
		{ open: '(', close: ')', token: 'delimiter.parenthesis' },
		{ open: '{', close: '}', token: 'delimiter.curly' },
		{ open: '[', close: ']', token: 'delimiter.square' }
	],

	// we include these common regular expressions
	symbols: /[=&gt;&lt;!~?:&amp;|+\-*\/\^%\.]+/,

	// escape sequences
	escape: /(?:[abefnrstv\\"'\n\r]|[0-7]{1,3}|x[0-9A-Fa-f]{1,2}|u[0-9A-Fa-f]{4})/,
	escapes: /\\(?:C\-(@escape|.)|c(@escape|.)|@escape)/,

	decpart: /\d(_?\d)*/,
	decimal: /0|@decpart/,

	delim: /[^a-zA-Z0-9\s\n\r]/,
	heredelim: /(?:\w+|'[^']*'|"[^"]*"|`[^`]*`)/,

	regexpctl: /[(){}\[\]\$\^|\-*+?\.]/,
	regexpesc: /\\(?:[AzZbBdDfnrstvwWn0\\\/]|@regexpctl|c[A-Z]|x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4})?/,


	// The main tokenizer for our languages
	tokenizer: {
		// Main entry.
		// root.&lt;decl&gt; where decl is the current opening declaration (like 'class')
		root: [
			// identifiers and keywords
			// most complexity here is due to matching 'end' correctly with declarations.
			// We distinguish a declaration that comes first on a line, versus declarations further on a line (which are most likey modifiers)
			[/^(\s*)([a-z_]\w*[!?=]?)/, ['white',
				{
					cases: {
						'for|until|while': { token: 'keyword.$2', next: '@dodecl.$2' },
						'@declarations': { token: 'keyword.$2', next: '@root.$2' },
						'end': { token: 'keyword.$S2', next: '@pop' },
						'@keywords': 'keyword',
						'@builtins': 'predefined',
						'@default': 'identifier'
					}
				}]],
			[/[a-z_]\w*[!?=]?/,
				{
					cases: {
						'if|unless|while|until': { token: 'keyword.$0x', next: '@modifier.$0x' },
						'for': { token: 'keyword.$2', next: '@dodecl.$2' },
						'@linedecls': { token: 'keyword.$0', next: '@root.$0' },
						'end': { token: 'keyword.$S2', next: '@pop' },
						'@keywords': 'keyword',
						'@builtins': 'predefined',
						'@default': 'identifier'
					}
				}],

			[/[A-Z][\w]*[!?=]?/, 'constructor.identifier'],     // constant
			[/\$[\w]*/, 'global.constant'],               // global
			[/@[\w]*/, 'namespace.instance.identifier'], // instance
			[/@@[\w]*/, 'namespace.class.identifier'],    // class

			// here document
			[/&lt;&lt;[-~](@heredelim).*/, { token: 'string.heredoc.delimiter', next: '@heredoc.$1' }],
			[/[ \t\r\n]+&lt;&lt;(@heredelim).*/, { token: 'string.heredoc.delimiter', next: '@heredoc.$1' }],
			[/^&lt;&lt;(@heredelim).*/, { token: 'string.heredoc.delimiter', next: '@heredoc.$1' }],


			// whitespace
			{ include: '@whitespace' },

			// strings
			[/"/, { token: 'string.d.delim', next: '@dstring.d."' }],
			[/'/, { token: 'string.sq.delim', next: '@sstring.sq' }],

			// % literals. For efficiency, rematch in the 'pstring' state
			[/%([rsqxwW]|Q?)/, { token: '@rematch', next: 'pstring' }],

			// commands and symbols
			[/`/, { token: 'string.x.delim', next: '@dstring.x.`' }],
			[/:(\w|[$@])\w*[!?=]?/, 'string.s'],
			[/:"/, { token: 'string.s.delim', next: '@dstring.s."' }],
			[/:'/, { token: 'string.s.delim', next: '@sstring.s' }],

			// regular expressions. Lookahead for a (not escaped) closing forwardslash on the same line
			[/\/(?=(\\\/|[^\/\n])+\/)/, { token: 'regexp.delim', next: '@regexp' }],

			// delimiters and operators
			[/[{}()\[\]]/, '@brackets'],
			[/@symbols/, {
				cases: {
					'@keywordops': 'keyword',
					'@operators': 'operator',
					'@default': ''
				}
			}],

			[/[;,]/, 'delimiter'],

			// numbers
			[/0[xX][0-9a-fA-F](_?[0-9a-fA-F])*/, 'number.hex'],
			[/0[_oO][0-7](_?[0-7])*/, 'number.octal'],
			[/0[bB][01](_?[01])*/, 'number.binary'],
			[/0[dD]@decpart/, 'number'],
			[/@decimal((\.@decpart)?([eE][\-+]?@decpart)?)/, {
				cases: {
					'$1': 'number.float',
					'@default': 'number'
				}
			}],

		],

		// used to not treat a 'do' as a block opener if it occurs on the same
		// line as a 'do' statement: 'while|until|for'
		// dodecl.&lt;decl&gt; where decl is the declarations started, like 'while'
		dodecl: [
			[/^/, { token: '', switchTo: '@root.$S2' }], // get out of do-skipping mode on a new line
			[/[a-z_]\w*[!?=]?/, {
				cases: {
					'end': { token: 'keyword.$S2', next: '@pop' }, // end on same line
					'do': { token: 'keyword', switchTo: '@root.$S2' }, // do on same line: not an open bracket here
					'@linedecls': { token: '@rematch', switchTo: '@root.$S2' }, // other declaration on same line: rematch
					'@keywords': 'keyword',
					'@builtins': 'predefined',
					'@default': 'identifier'
				}
			}],
			{ include: '@root' }
		],

		// used to prevent potential modifiers ('if|until|while|unless') to match
		// with 'end' keywords.
		// modifier.&lt;decl&gt;x where decl is the declaration starter, like 'if'
		modifier: [
			[/^/, '', '@pop'], // it was a modifier: get out of modifier mode on a new line
			[/[a-z_]\w*[!?=]?/, {
				cases: {
					'end': { token: 'keyword.$S2', next: '@pop' }, // end on same line
					'then|else|elsif|do': { token: 'keyword', switchTo: '@root.$S2' }, // real declaration and not a modifier
					'@linedecls': { token: '@rematch', switchTo: '@root.$S2' }, // other declaration =&gt; not a modifier
					'@keywords': 'keyword',
					'@builtins': 'predefined',
					'@default': 'identifier'
				}
			}],
			{ include: '@root' }
		],

		// single quote strings (also used for symbols)
		// sstring.&lt;kind&gt;  where kind is 'sq' (single quote) or 's' (symbol)
		sstring: [
			[/[^\\']+/, 'string.$S2'],
			[/\\\\|\\'|\\$/, 'string.$S2.escape'],
			[/\\./, 'string.$S2.invalid'],
			[/'/, { token: 'string.$S2.delim', next: '@pop' }]
		],

		// double quoted "string".
		// dstring.&lt;kind&gt;.&lt;delim&gt; where kind is 'd' (double quoted), 'x' (command), or 's' (symbol)
		// and delim is the ending delimiter (" or `)
		dstring: [
			[/[^\\`"#]+/, 'string.$S2'],
			[/#/, 'string.$S2.escape', '@interpolated'],
			[/\\$/, 'string.$S2.escape'],
			[/@escapes/, 'string.$S2.escape'],
			[/\\./, 'string.$S2.escape.invalid'],
			[/[`"]/, {
				cases: {
					'$#==$S3': { token: 'string.$S2.delim', next: '@pop' },
					'@default': 'string.$S2'
				}
			}]
		],

		// literal documents
		// heredoc.&lt;close&gt; where close is the closing delimiter
		heredoc: [
			[/^(\s*)(@heredelim)$/, {
				cases: {
					'$2==$S2': ['string.heredoc', { token: 'string.heredoc.delimiter', next: '@pop' }],
					'@default': ['string.heredoc', 'string.heredoc']
				}
			}],
			[/.*/, 'string.heredoc'],
		],

		// interpolated sequence
		interpolated: [
			[/\$\w*/, 'global.constant', '@pop'],
			[/@\w*/, 'namespace.class.identifier', '@pop'],
			[/@@\w*/, 'namespace.instance.identifier', '@pop'],
			[/[{]/, { token: 'string.escape.curly', switchTo: '@interpolated_compound' }],
			['', '', '@pop'], // just a # is interpreted as a #
		],

		// any code
		interpolated_compound: [
			[/[}]/, { token: 'string.escape.curly', next: '@pop' }],
			{ include: '@root' },
		],

		// %r quoted regexp
		// pregexp.&lt;open&gt;.&lt;close&gt; where open/close are the open/close delimiter
		pregexp: [
			{ include: '@whitespace' },
			// turns out that you can quote using regex control characters, aargh!
			// for example; %r|kgjgaj| is ok (even though | is used for alternation)
			// so, we need to match those first
			[/[^\(\{\[\\]/, {
				cases: {
					'$#==$S3': { token: 'regexp.delim', next: '@pop' },
					'$#==$S2': { token: 'regexp.delim', next: '@push' }, // nested delimiters are allowed..
					'~[)}\\]]': '@brackets.regexp.escape.control',
					'~@regexpctl': 'regexp.escape.control',
					'@default': 'regexp'
				}
			}],
			{ include: '@regexcontrol' },
		],

		// We match regular expression quite precisely
		regexp: [
			{ include: '@regexcontrol' },
			[/[^\\\/]/, 'regexp'],
			['/[ixmp]*', { token: 'regexp.delim' }, '@pop'],
		],

		regexcontrol: [
			[/(\{)(\d+(?:,\d*)?)(\})/, ['@brackets.regexp.escape.control', 'regexp.escape.control', '@brackets.regexp.escape.control']],
			[/(\[)(\^?)/, ['@brackets.regexp.escape.control', { token: 'regexp.escape.control', next: '@regexrange' }]],
			[/(\()(\?[:=!])/, ['@brackets.regexp.escape.control', 'regexp.escape.control']],
			[/\(\?#/, { token: 'regexp.escape.control', next: '@regexpcomment' }],
			[/[()]/, '@brackets.regexp.escape.control'],
			[/@regexpctl/, 'regexp.escape.control'],
			[/\\$/, 'regexp.escape'],
			[/@regexpesc/, 'regexp.escape'],
			[/\\\./, 'regexp.invalid'],
			[/#/, 'regexp.escape', '@interpolated'],
		],

		regexrange: [
			[/-/, 'regexp.escape.control'],
			[/\^/, 'regexp.invalid'],
			[/\\$/, 'regexp.escape'],
			[/@regexpesc/, 'regexp.escape'],
			[/[^\]]/, 'regexp'],
			[/\]/, '@brackets.regexp.escape.control', '@pop'],
		],

		regexpcomment: [
			[/[^)]+/, 'comment'],
			[/\)/, { token: 'regexp.escape.control', next: '@pop' }]
		],


		// % quoted strings
		// A bit repetitive since we need to often special case the kind of ending delimiter
		pstring: [
			[/%([qws])\(/, { token: 'string.$1.delim', switchTo: '@qstring.$1.(.)' }],
			[/%([qws])\[/, { token: 'string.$1.delim', switchTo: '@qstring.$1.[.]' }],
			[/%([qws])\{/, { token: 'string.$1.delim', switchTo: '@qstring.$1.{.}' }],
			[/%([qws])&lt;/, { token: 'string.$1.delim', switchTo: '@qstring.$1.&lt;.&gt;' }],
			[/%([qws])(@delim)/, { token: 'string.$1.delim', switchTo: '@qstring.$1.$2.$2' }],

			[/%r\(/, { token: 'regexp.delim', switchTo: '@pregexp.(.)' }],
			[/%r\[/, { token: 'regexp.delim', switchTo: '@pregexp.[.]' }],
			[/%r\{/, { token: 'regexp.delim', switchTo: '@pregexp.{.}' }],
			[/%r&lt;/, { token: 'regexp.delim', switchTo: '@pregexp.&lt;.&gt;' }],
			[/%r(@delim)/, { token: 'regexp.delim', switchTo: '@pregexp.$1.$1' }],

			[/%(x|W|Q?)\(/, { token: 'string.$1.delim', switchTo: '@qqstring.$1.(.)' }],
			[/%(x|W|Q?)\[/, { token: 'string.$1.delim', switchTo: '@qqstring.$1.[.]' }],
			[/%(x|W|Q?)\{/, { token: 'string.$1.delim', switchTo: '@qqstring.$1.{.}' }],
			[/%(x|W|Q?)&lt;/, { token: 'string.$1.delim', switchTo: '@qqstring.$1.&lt;.&gt;' }],
			[/%(x|W|Q?)(@delim)/, { token: 'string.$1.delim', switchTo: '@qqstring.$1.$2.$2' }],

			[/%([rqwsxW]|Q?)./, { token: 'invalid', next: '@pop' }], // recover
			[/./, { token: 'invalid', next: '@pop' }], // recover
		],

		// non-expanded quoted string.
		// qstring.&lt;kind&gt;.&lt;open&gt;.&lt;close&gt;
		//  kind = q|w|s  (single quote, array, symbol)
		//  open = open delimiter
		//  close = close delimiter
		qstring: [
			[/\\$/, 'string.$S2.escape'],
			[/\\./, 'string.$S2.escape'],
			[/./, {
				cases: {
					'$#==$S4': { token: 'string.$S2.delim', next: '@pop' },
					'$#==$S3': { token: 'string.$S2.delim', next: '@push' }, // nested delimiters are allowed..
					'@default': 'string.$S2'
				}
			}],
		],

		// expanded quoted string.
		// qqstring.&lt;kind&gt;.&lt;open&gt;.&lt;close&gt;
		//  kind = Q|W|x  (double quote, array, command)
		//  open = open delimiter
		//  close = close delimiter
		qqstring: [
			[/#/, 'string.$S2.escape', '@interpolated'],
			{ include: '@qstring' }
		],


		// whitespace &amp; comments
		whitespace: [
			[/[ \t\r\n]+/, ''],
			[/^\s*=begin\b/, 'comment', '@comment'],
			[/#.*$/, 'comment'],
		],

		comment: [
			[/[^=]+/, 'comment'],
			[/^\s*=begin\b/, 'comment.invalid'],    // nested comment
			[/^\s*=end\b.*/, 'comment', '@pop'],
			[/[=]/, 'comment']
		],
	}
};
</pre
				>

				<pre id="python-sample">
from Tkinter   import *
import Pmw, string

class SLabel(Frame):
    """ SLabel defines a 2-sided label within a Frame. The
        left hand label has blue letters the right has white letters """
    def __init__(self, master, leftl, rightl):
        Frame.__init__(self, master, bg='gray40')
        self.pack(side=LEFT, expand=YES, fill=BOTH)
        Label(self, text=leftl, fg='steelblue1',
                     font=("arial", 6, "bold"), width=5, bg='gray40').pack(
                         side=LEFT, expand=YES, fill=BOTH)
        Label(self, text=rightl, fg='white',
                     font=("arial", 6, "bold"), width=1, bg='gray40').pack(
                         side=RIGHT, expand=YES, fill=BOTH)

class Key(Button):
    def __init__(self, master, font=('arial', 8, 'bold'),
                 fg='white',width=5, borderwidth=5, **kw):
        kw['font'] = font
        kw['fg'] = fg
        kw['width'] = width
        kw['borderwidth'] = borderwidth
        apply(Button.__init__, (self, master), kw)
        self.pack(side=LEFT, expand=NO, fill=NONE)

class Calculator(Frame):
    def __init__(self, parent=None):
        Frame.__init__(self, bg='gray40')
        self.pack(expand=YES, fill=BOTH)
        self.master.title('Tkinter Toolkit TT-42')
        self.master.iconname('Tk-42')
        self.calc = Evaluator()        # This is our evaluator
        self.buildCalculator()         # Build the widgets
        # This is an incomplete dictionary - a good exercise!
        self.actionDict = {'second': self.doThis, 'mode':    self.doThis,
                           'delete': self.doThis, 'alpha':   self.doThis,
                           'stat':   self.doThis, 'math':    self.doThis,
                           'matrix': self.doThis, 'program': self.doThis,
                           'vars':   self.doThis, 'clear':   self.clearall,
                           'sin':    self.doThis, 'cos':     self.doThis,
                           'tan':    self.doThis, 'up':      self.doThis,
                           'X1':     self.doThis, 'X2':      self.doThis,
                           'log':    self.doThis, 'ln':      self.doThis,
                           'store':  self.doThis, 'off':     self.turnoff,
                           'neg':    self.doThis, 'enter':   self.doEnter,
                           }
        self.current = ""

    def doThis(self,action):
        print '"%s" has not been implemented' % action

    def turnoff(self, *args):
        self.quit()

    def clearall(self, *args):
        self.current = ""
        self.display.component('text').delete(1.0, END)

    def doEnter(self, *args):
        result = self.calc.runpython(self.current)
        if result:
            self.display.insert(END, '\n')
            self.display.insert(END, '%s\n' % result, 'ans')
        self.current = ""

    def doKeypress(self, event):
        key = event.char
        if not key in ['\b']:
            self.current = self.current + event.char
        if key == '\b':
            self.current = self.current[:-1]

    def keyAction(self, key):
        self.display.insert(END, key)
        self.current = self.current + key

    def evalAction(self, action):
  try:
            self.actionDict[action](action)
  except KeyError:
            pass

    def buildCalculator(self):
        FUN   = 1            # Designates a Function
        KEY   = 0            # Designates a Key
        KC1   = 'gray30'     # Dark Keys
        KC2   = 'gray50'     # Light Keys
        KC3   = 'steelblue1' # Light Blue Key
        KC4   = 'steelblue'  # Dark Blue Key
        keys = [
            [('2nd',  '',     '',  KC3, FUN, 'second'),  # Row 1
             ('Mode', 'Quit', '',  KC1, FUN, 'mode'),
             ('Del',  'Ins',  '',  KC1, FUN, 'delete'),
             ('Alpha','Lock', '',  KC2, FUN, 'alpha'),
             ('Stat', 'List', '',  KC1, FUN, 'stat')],
            [('Math', 'Test', 'A', KC1, FUN, 'math'),    # Row 2
             ('Mtrx', 'Angle','B', KC1, FUN, 'matrix'),
             ('Prgm', 'Draw', 'C', KC1, FUN, 'program'),
             ('Vars', 'YVars','',  KC1, FUN, 'vars'),
             ('Clr',  '',     '',  KC1, FUN, 'clear')],
            [('X-1',  'Abs',  'D', KC1, FUN, 'X1'),      # Row 3
             ('Sin',  'Sin-1','E', KC1, FUN, 'sin'),
             ('Cos',  'Cos-1','F', KC1, FUN, 'cos'),
             ('Tan',  'Tan-1','G', KC1, FUN, 'tan'),
             ('^',    'PI',   'H', KC1, FUN, 'up')],
            [('X2',   'Root', 'I', KC1, FUN, 'X2'),      # Row 4
             (',',    'EE',   'J', KC1, KEY, ','),
             ('(',    '{',    'K', KC1, KEY, '('),
             (')',    '}',    'L', KC1, KEY, ')'),
             ('/',    '',     'M', KC4, KEY, '/')],
            [('Log',  '10x',  'N', KC1, FUN, 'log'),     # Row 5
             ('7',    'Un-1', 'O', KC2, KEY, '7'),
             ('8',    'Vn-1', 'P', KC2, KEY, '8'),
             ('9',    'n',    'Q', KC2, KEY, '9'),
             ('X',    '[',    'R', KC4, KEY, '*')],
            [('Ln',   'ex',   'S', KC1, FUN, 'ln'),      # Row 6
             ('4',    'L4',   'T', KC2, KEY, '4'),
             ('5',    'L5',   'U', KC2, KEY, '5'),
             ('6',    'L6',   'V', KC2, KEY, '6'),
             ('-',    ']',    'W', KC4, KEY, '-')],
            [('STO',  'RCL',  'X', KC1, FUN, 'store'),   # Row 7
             ('1',    'L1',   'Y', KC2, KEY, '1'),
             ('2',    'L2',   'Z', KC2, KEY, '2'),
             ('3',    'L3',   '',  KC2, KEY, '3'),
             ('+',    'MEM',  '"', KC4, KEY, '+')],
            [('Off',  '',     '',  KC1, FUN, 'off'),     # Row 8
             ('0',    '',     '',  KC2, KEY, '0'),
             ('.',    ':',    '',  KC2, KEY, '.'),
             ('(-)',  'ANS',  '?', KC2, FUN, 'neg'),
             ('Enter','Entry','',  KC4, FUN, 'enter')]]

        self.display = Pmw.ScrolledText(self, hscrollmode='dynamic',
                      vscrollmode='dynamic', hull_relief='sunken',
                      hull_background='gray40', hull_borderwidth=10,
                      text_background='honeydew4', text_width=16,
                      text_foreground='black', text_height=6,
          text_padx=10, text_pady=10, text_relief='groove',
                      text_font=('arial', 12, 'bold'))
        self.display.pack(side=TOP, expand=YES, fill=BOTH)
        self.display.tag_config('ans', foreground='white')
        self.display.component('text').bind('&lt;Key>', self.doKeypress)
        self.display.component('text').bind('&lt;Return>', self.doEnter)

        for row in keys:
            rowa = Frame(self, bg='gray40')
            rowb = Frame(self, bg='gray40')
            for p1, p2, p3, color, ktype, func in row:
                if ktype == FUN:
                    a = lambda s=self, a=func: s.evalAction(a)
                else:
                    a = lambda s=self, k=func: s.keyAction(k)
                SLabel(rowa, p2, p3)
                Key(rowb, text=p1, bg=color, command=a)
            rowa.pack(side=TOP, expand=YES, fill=BOTH)
            rowb.pack(side=TOP, expand=YES, fill=BOTH)

class Evaluator:
    def __init__(self):
        self.myNameSpace = {}
        self.runpython("from math import *")

    def runpython(self, code):
        try:
            return 'eval(code, self.myNameSpace, self.myNameSpace)'
        except SyntaxError:
            try:
                exec code in self.myNameSpace, self.myNameSpace
            except:
                return 'Error'

Calculator().mainloop()
</pre
				>
				<pre id="python">
// Difficulty: "Moderate"
// Python language definition.
// Only trickiness is that we need to check strings before identifiers
// since they have letter prefixes. We also treat ':' as an @open bracket
// in order to get auto identation.
return {
	defaultToken: '',
	tokenPostfix: '.python',

	keywords: [
		'and',
		'as',
		'assert',
		'break',
		'class',
		'continue',
		'def',
		'del',
		'elif',
		'else',
		'except',
		'exec',
		'finally',
		'for',
		'from',
		'global',
		'if',
		'import',
		'in',
		'is',
		'lambda',
		'None',
		'not',
		'or',
		'pass',
		'print',
		'raise',
		'return',
		'self',
		'try',
		'while',
		'with',
		'yield',

		'int',
		'float',
		'long',
		'complex',
		'hex',

		'abs',
		'all',
		'any',
		'apply',
		'basestring',
		'bin',
		'bool',
		'buffer',
		'bytearray',
		'callable',
		'chr',
		'classmethod',
		'cmp',
		'coerce',
		'compile',
		'complex',
		'delattr',
		'dict',
		'dir',
		'divmod',
		'enumerate',
		'eval',
		'execfile',
		'file',
		'filter',
		'format',
		'frozenset',
		'getattr',
		'globals',
		'hasattr',
		'hash',
		'help',
		'id',
		'input',
		'intern',
		'isinstance',
		'issubclass',
		'iter',
		'len',
		'locals',
		'list',
		'map',
		'max',
		'memoryview',
		'min',
		'next',
		'object',
		'oct',
		'open',
		'ord',
		'pow',
		'print',
		'property',
		'reversed',
		'range',
		'raw_input',
		'reduce',
		'reload',
		'repr',
		'reversed',
		'round',
		'set',
		'setattr',
		'slice',
		'sorted',
		'staticmethod',
		'str',
		'sum',
		'super',
		'tuple',
		'type',
		'unichr',
		'unicode',
		'vars',
		'xrange',
		'zip',

		'True',
		'False',

		'__dict__',
		'__methods__',
		'__members__',
		'__class__',
		'__bases__',
		'__name__',
		'__mro__',
		'__subclasses__',
		'__init__',
		'__import__'
	],

	brackets: [
		{ open: '{', close: '}', token: 'delimiter.curly' },
		{ open: '[', close: ']', token: 'delimiter.bracket' },
		{ open: '(', close: ')', token: 'delimiter.parenthesis' }
	],

	tokenizer: {
		root: [
			{ include: '@whitespace' },
			{ include: '@numbers' },
			{ include: '@strings' },

			[/[,:;]/, 'delimiter'],
			[/[{}\[\]()]/, '@brackets'],

			[/@[a-zA-Z]\w*/, 'tag'],
			[/[a-zA-Z]\w*/, {
				cases: {
					'@keywords': 'keyword',
					'@default': 'identifier'
				}
			}]
		],

		// Deal with white space, including single and multi-line comments
		whitespace: [
			[/\s+/, 'white'],
			[/(^#.*$)/, 'comment'],
			[/('''.*''')|(""".*""")/, 'string'],
			[/'''.*$/, 'string', '@endDocString'],
			[/""".*$/, 'string', '@endDblDocString']
		],
		endDocString: [
			[/\\'/, 'string'],
			[/.*'''/, 'string', '@popall'],
			[/.*$/, 'string']
		],
		endDblDocString: [
			[/\\"/, 'string'],
			[/.*"""/, 'string', '@popall'],
			[/.*$/, 'string']
		],

		// Recognize hex, negatives, decimals, imaginaries, longs, and scientific notation
		numbers: [
			[/-?0x([abcdef]|[ABCDEF]|\d)+[lL]?/, 'number.hex'],
			[/-?(\d*\.)?\d+([eE][+\-]?\d+)?[jJ]?[lL]?/, 'number']
		],

		// Recognize strings, including those broken across lines with \ (but not without)
		strings: [
			[/'$/, 'string.escape', '@popall'],
			[/'/, 'string.escape', '@stringBody'],
			[/"$/, 'string.escape', '@popall'],
			[/"/, 'string.escape', '@dblStringBody']
		],
		stringBody: [
			[/[^\\']+$/, 'string', '@popall'],
			[/[^\\']+/, 'string'],
			[/\\./, 'string'],
			[/'/, 'string.escape', '@popall'],
			[/\\$/, 'string']
		],
		dblStringBody: [
			[/[^\\"]+$/, 'string', '@popall'],
			[/[^\\"]+/, 'string'],
			[/\\./, 'string'],
			[/"/, 'string.escape', '@popall'],
			[/\\$/, 'string']
		]
	}
};
</pre
				>

				<pre id="z3python-sample">
# 9x9 matrix of integer variables
X = [ [ Int("x_%s_%s" % (i+1, j+1)) for j in range(9) ]
      for i in range(9) ]

# each cell contains a value in {1, ..., 9}
cells_c  = [ And(1 &lt;= X[i][j], X[i][j] &lt;= 9)
             for i in range(9) for j in range(9) ]

# each row contains a digit at most once
rows_c   = [ Distinct(X[i]) for i in range(9) ]

# each column contains a digit at most once
cols_c   = [ Distinct([ X[i][j] for i in range(9) ])
             for j in range(9) ]

# each 3x3 square contains a digit at most once
sq_c     = [ Distinct([ X[3*i0 + i][3*j0 + j]
                        for i in range(3) for j in range(3) ])
             for i0 in range(3) for j0 in range(3) ]

sudoku_c = cells_c + rows_c + cols_c + sq_c

# sudoku instance, we use '0' for empty cells
instance = ((0,0,0,0,9,4,0,3,0),
            (0,0,0,5,1,0,0,0,7),
            (0,8,9,0,0,0,0,4,0),
            (0,0,0,0,0,0,2,0,8),
            (0,6,0,2,0,1,0,5,0),
            (1,0,2,0,0,0,0,0,0),
            (0,7,0,0,0,0,5,2,0),
            (9,0,0,0,6,5,0,0,0),
            (0,4,0,9,7,0,0,0,0))

instance_c = [ If(instance[i][j] == 0,
                  True,
                  X[i][j] == instance[i][j])
               for i in range(9) for j in range(9) ]

s = Solver()
s.add(sudoku_c + instance_c)
if s.check() == sat:
    m = s.model()
    r = [ [ m.evaluate(X[i][j]) for j in range(9) ]
          for i in range(9) ]
    print_matrix(r)
else:
    print "failed to solve"
</pre
				>

				<pre id="z3python">
// Difficulty: "Moderate"
// This is the Python language definition but specialized for use with Z3
// See also: http://www.rise4fun.com/Z3Py
return {

  // Set defaultToken to invalid to see what you do not tokenize yet
  // defaultToken: 'invalid',

  keywords: [
    'and', 'del', 'from', 'not', 'while',
    'as', 'elif', 'global', 'or', 'with',
    'assert', 'else', 'if', 'pass', 'yield',
    'break', 'except', 'import', 'print',
    'class', 'exec', 'in', 'raise', 'continue', 'finally', 'is',
    'return', 'def', 'for', 'lambda', 'try',
    ':','=',
    'isinstance','__debug__',
  ],

  operators: [
    '+', '-', '*', '**', '/', '//', '%',
    '&lt;&lt;', '&gt;&gt;', '&amp;', '|', '^', '~',
    '&lt;', '&gt;', '&lt;=', '&gt;=', '==', '!=', '&lt;&gt;',
    '+=', '-=', '*=', '/=', '//=', '%=',
    '&amp;=', '|=', '^=', '&gt;&gt;=', '&lt;&lt;=', '**=',
  ],

  builtins: [
    'set_option', 'solve', 'simplify', 'Int', 'Real', 'Bool', 'open_log',
    'append_log', 'is_sort', 'DeclareSort', 'Function', 'is_func_decl', 'is_expr',
    'is_app', 'is_const', 'is_var', 'get_var_index', 'is_app_of',
    'If', 'Distinct', 'Const', 'Consts', 'Var', 'is_bool',
    'is_true', 'is_false', 'is_and', 'is_or', 'is_not', 'is_eq',
    'BoolSort', 'BoolVal', 'Bools', 'BoolVector', 'FreshBool',
    'Implies', 'Not', 'And', 'Or', 'MultiPattern', 'ForAll',
    'Exists', 'is_int', 'is_real', 'is_int_value', 'is_rational_value',
    'is_algebraic_value', 'IntSort', 'RealSort', 'IntVal',
    'RealVal', 'RatVal', 'Q', 'Ints', 'Reals', 'IntVector', 'RealVector',
    'FreshInt', 'FreshReal', 'ToReal', 'ToInt', 'IsInt',
    'Sqrt', 'Cbrt', 'is_bv', 'BV2Int', 'BitVecSort', 'BitVecVal',
    'BitVec', 'BitVecs', 'Concat', 'Extract', 'ULE', 'ULT',
    'UGE', 'UGT', 'UDiv', 'URem', 'SRem', 'LShR', 'RotateLeft',
    'RotateRight', 'SignExt', 'ZeroExt', 'RepeatBitVec',
    'is_array', 'ArraySort', 'Array', 'Update', 'Store',
    'Select', 'Map', 'K', 'CreateDatatypes', 'EnumSort', 'Solver',
    'SolverFor', 'SimpleSolver', 'FixedPoint', 'Tactic', 'AndThen',
    'Then', 'OrElse', 'ParOr', 'ParThen', 'ParAndThen',
    'With', 'Repeat', 'TryFor', 'Probe', 'When', 'FailIf', 'Cond',
    'substitute', 'Sum', 'Product', 'solve_using', 'prove', 'init', 'sat', 'unsat',
    'unknown'
   ],

  brackets: [
    ['(',')','delimiter.parenthesis'],
    ['{','}','delimiter.curly'],
    ['[',']','delimiter.square']
  ],

  // operator symbols
  symbols:    /[=&gt;&lt;!~&amp;|+\-*\/\^%]+/,
  delimiters: /[;=.@:,`]/,

  // strings
  escapes: /\\(?:[abfnrtv\\"'\n\r]|x[0-9A-Fa-f]{2}|[0-7]{3}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8}|N\{\w+\})/,
  rawpre: /(?:[rR]|ur|Ur|uR|UR|br|Br|bR|BR)/,
  strpre: /(?:[buBU])/,

  // The main tokenizer for our languages
  tokenizer: {
    root: [
      // strings: need to check first due to the prefix
      [/@strpre?("""|''')/, { token: 'string.delim', bracket: '@open', next: '@mstring.$1' } ],
      [/@strpre?"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/@strpre?'([^'\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/@strpre?(["'])/,  { token: 'string.delim', bracket: '@open', next: '@string.$1' } ],

      [/@rawpre("""|''')/, { token: 'string.delim', bracket: '@open', next: '@mrawstring.$1' } ],
      [/@rawpre"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/@rawpre'([^'\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/@rawpre(["'])/,  { token: 'string.delim', bracket: '@open', next: '@rawstring.$1' } ],

      // identifiers and keywords
      [/__[\w$]*/, 'predefined' ],
      [/[a-z_$][\w$]*/, { cases: { '@keywords': 'keyword',
                                   '@builtins': 'constructor.identifier',
                                   '@default': 'identifier' } }],
      [/[A-Z][\w]*/, { cases: { '~[A-Z0-9_]+': 'constructor.identifier',
                                '@builtins'  : 'constructor.identifier',
                                '@default'   : 'namespace.identifier' }}],  // to show class names nicely

      // whitespace
      { include: '@whitespace' },

      // delimiters and operators
      [/[{}()\[\]]/, '@brackets'],
      [/@symbols/, { cases: { '@keywords' : 'keyword',
                              '@operators': 'operator',
                              '@default'  : '' } } ],

      // numbers
      [/\d*\.\d+([eE][\-+]?\d+)?/,   'number.float'],
      [/0[xX][0-9a-fA-F]+[lL]?/,     'number.hex'],
      [/0[bB][0-1]+[lL]?/,           'number.binary'],
      [/(0[oO][0-7]+|0[0-7]+)[lL]?/, 'number.octal'],
      [/(0|[1-9]\d*)[lL]?/,          'number'],

      // delimiter: after number because of .\d floats
      [':', { token: 'keyword', bracket: '@open' }], // bracket for indentation
      [/@delimiters/, { cases: { '@keywords': 'keyword',
                                 '@default': 'delimiter' }}],

    ],

    comment: [
      [/[^\/*]+/, 'comment' ],
      [/\/\*/,    'comment', '@push' ],    // nested comment
      ["\\*/",    'comment', '@pop'  ],
      [/[\/*]/,   'comment' ]
    ],

    // Regular strings
    mstring: [
      { include: '@strcontent' },
      [/"""|'''/,  { cases: { '$#==$S2':  { token: 'string.delim', bracket: '@close', next: '@pop' },
                              '@default': { token: 'string' } } }],
      [/["']/, 'string' ],
      [/./,    'string.invalid'],
    ],

    string: [
      { include: '@strcontent' },
      [/["']/, { cases: { '$#==$S2': { token: 'string.delim', bracket: '@close', next: '@pop' },
                          '@default': { token: 'string' } } } ],
      [/./, 'string.invalid'],
    ],

    strcontent: [
      [/[^\\"']+/,  'string'],
      [/\\$/,       'string.escape'],
      [/@escapes/,  'string.escape'],
      [/\\./,       'string.escape.invalid'],
    ],

    // Raw strings: we distinguish them to color escape sequences correctly
    mrawstring: [
      { include: '@rawstrcontent' },
      [/"""|'''/,  { cases: { '$#==$S2':  { token: 'string.delim', bracket: '@close', next: '@pop' },
                              '@default': { token: 'string' } } }],
      [/["']/, 'string' ],
      [/./,    'string.invalid'],
    ],

    rawstring: [
      { include: '@rawstrcontent' },
      [/["']/, { cases: { '$#==$S2': { token: 'string.delim', bracket: '@close', next: '@pop' },
                          '@default': { token: 'string' } } } ],
      [/./, 'string.invalid'],
    ],

    rawstrcontent: [
      [/[^\\"']+/, 'string'],
      [/\\["']/,   'string'],
      [/\\u[0-9A-Fa-f]{4}/, 'string.escape'],
      [/\\/, 'string' ],
    ],

    // whitespace
    whitespace: [
      [/[ \t\r\n]+/, 'white'],
      [/#.*$/,       'comment'],
    ],
  },
};
</pre
				>

				<pre id="smt2-sample">
; This example illustrates different uses of the arrays
; supported in Z3.
; This includes Combinatory Array Logic (de Moura &amp; Bjorner, FMCAD 2009).
;
(define-sort A () (Array Int Int))
(declare-fun x () Int)
(declare-fun y () Int)
(declare-fun z () Int)
(declare-fun a1 () A)
(declare-fun a2 () A)
(declare-fun a3 () A)
(push) ; illustrate select-store
(assert (= (select a1 x) x))
(assert (= (store a1 x y) a1))
(check-sat)
(get-model)
(assert (not (= x y)))
(check-sat)
(pop)
(define-fun all1_array () A ((as const A) 1))
(simplify (select all1_array x))
(define-sort IntSet () (Array Int Bool))
(declare-fun a () IntSet)
(declare-fun b () IntSet)
(declare-fun c () IntSet)
(push) ; illustrate map
(assert (not (= ((_ map and) a b) ((_ map not) ((_ map or) ((_ map not) b) ((_ map not) a))))))
(check-sat)
(pop)
(push)
(assert (and (select ((_ map and) a b) x) (not (select a x))))
(check-sat)
(pop)
(push)
(assert (and (select ((_ map or) a b) x) (not (select a x))))
(check-sat)
(get-model)
(assert (and (not (select b x))))
(check-sat)
;; unsat, so there is no model.
(pop)
(push) ; illustrate default
(assert (= (default a1) 1))
(assert (not (= a1 ((as const A) 1))))
(check-sat)
(get-model)
(assert (= (default a2) 1))
(assert (not (= a1 a2)))
(check-sat)
(get-model)
(pop)
(exit)
</pre
				>
				<pre id="smt2">
// Difficulty: "Easy"
// SMT 2.0 language
// See http://www.rise4fun.com/z3 or http://www.smtlib.org/ for more information
return {

  // Set defaultToken to invalid to see what you do not tokenize yet
  // defaultToken: 'invalid',

  keywords: [
    'define-fun', 'define-const', 'assert', 'push', 'pop', 'assert', 'check-sat',
    'declare-const', 'declare-fun', 'get-model', 'get-value', 'declare-sort',
    'declare-datatypes', 'reset', 'eval', 'set-logic', 'help', 'get-assignment',
    'exit', 'get-proof', 'get-unsat-core', 'echo', 'let', 'forall', 'exists',
    'define-sort', 'set-option', 'get-option', 'set-info', 'check-sat-using', 'apply', 'simplify',
    'display', 'as', '!', 'get-info', 'declare-map', 'declare-rel', 'declare-var', 'rule',
    'query', 'get-user-tactics'
  ],

 operators: [
    '=', '&gt;', '&lt;', '&lt;=', '&gt;=', '=&gt;', '+', '-', '*', '/',
  ],

  builtins: [
    'mod', 'div', 'rem', '^', 'to_real', 'and', 'or', 'not', 'distinct',
    'to_int', 'is_int', '~', 'xor', 'if', 'ite', 'true', 'false', 'root-obj',
    'sat', 'unsat', 'const', 'map', 'store', 'select', 'sat', 'unsat',
    'bit1', 'bit0', 'bvneg', 'bvadd', 'bvsub', 'bvmul', 'bvsdiv', 'bvudiv', 'bvsrem',
    'bvurem', 'bvsmod',  'bvule', 'bvsle', 'bvuge', 'bvsge', 'bvult',
    'bvslt', 'bvugt', 'bvsgt', 'bvand', 'bvor', 'bvnot', 'bvxor', 'bvnand',
    'bvnor', 'bvxnor', 'concat', 'sign_extend', 'zero_extend', 'extract',
    'repeat', 'bvredor', 'bvredand', 'bvcomp', 'bvshl', 'bvlshr', 'bvashr',
    'rotate_left', 'rotate_right', 'get-assertions'
  ],

  brackets: [
    ['(',')','delimiter.parenthesis'],
    ['{','}','delimiter.curly'],
    ['[',']','delimiter.square']
  ],

  // we include these common regular expressions
  symbols:  /[=&gt;&lt;~&amp;|+\-*\/%@#]+/,

  // C# style strings
  escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,

  // The main tokenizer for our languages
  tokenizer: {
    root: [
      // identifiers and keywords
      [/[a-z_][\w\-\.']*/, { cases: { '@builtins': 'predefined.identifier',
                                      '@keywords': 'keyword',
                                      '@default': 'identifier' } }],
      [/[A-Z][\w\-\.']*/, 'type.identifier' ],
      [/[:][\w\-\.']*/, 'string.identifier' ],
      [/[$?][\w\-\.']*/, 'constructor.identifier' ],

      // whitespace
      { include: '@whitespace' },

      // delimiters and operators
      [/[()\[\]]/, '@brackets'],
      [/@symbols/, { cases: { '@operators': 'predefined.operator',
                              '@default'  : 'operator' } } ],


      // numbers
      [/\d*\.\d+([eE][\-+]?\d+)?/, 'number.float'],
      [/0[xX][0-9a-fA-F]+/, 'number.hex'],
      [/#[xX][0-9a-fA-F]+/, 'number.hex'],
      [/#b[0-1]+/, 'number.binary'],
      [/\d+/, 'number'],

      // delimiter: after number because of .\d floats
      [/[,.]/, 'delimiter'],

      // strings
      [/"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/"/,  { token: 'string.quote', bracket: '@open', next: '@string' } ],

      // user values
      [/\{/, { token: 'string.curly', bracket: '@open', next: '@uservalue' } ],
    ],

    uservalue: [
      [/[^\\\}]+/, 'string' ],
      [/\}/,       { token: 'string.curly', bracket: '@close', next: '@pop' } ],
      [/\\\}/,     'string.escape'],
      [/./,        'string']  // recover
    ],

    string: [
      [/[^\\"]+/,  'string'],
      [/@escapes/, 'string.escape'],
      [/\\./,      'string.escape.invalid'],
      [/"/,        { token: 'string.quote', bracket: '@close', next: '@pop' } ]
    ],

    whitespace: [
      [/[ \t\r\n]+/, 'white'],
      [/;.*$/,    'comment'],
    ],
  },
};
</pre
				>

				<pre id="xdot-sample">
digraph "If.try_if_then"
{
  label = "If.try_if_then";
  rankdir="TD";

  node [fontname="Helvetica", shape=record, fontsize="12", color="lightblue", style="filled"];

  edge [fontname="Helvetica", fontsize="10", color="black"];

  subgraph "cluster_node_57"
  { /* block node_57 */
  label = "";
  node_57 [label = "Block [57]"];
  node_58 [label = "Return [58@57]"];

  node_50 -> node_58 [label = "mem", dir = back];
  node_48 -> node_58 [label = "int", dir = back];
  } /* block node_57 */

  subgraph "cluster_node_43"
  { /* block node_43 */
  label = "";
  node_43 [label = "Block [43]"];
  node_50 [label = "Proj (mem) [50@43]"];

  node_45 -> node_50 [label = "tuple", dir = back];
  node_49 [label = "Proj (arg_2) [49@43]"];

  node_45 -> node_49 [label = "tuple", dir = back];
  node_48 [label = "Proj (arg_1) [48@43]"];

  node_45 -> node_48 [label = "tuple", dir = back];
  node_45 [label = "Start [45@43]"];

  node_51 [label = "Proj (exe(4)) [51@43]"];

  node_45 -> node_51 [label = "tuple", dir = back];
  } /* block node_43 */

  subgraph "cluster_node_52"
  { /* block node_52 */
  label = "";
  node_52 [label = "Block [52]"];
  node_56 [label = "Proj (exe(0)) [56@52]"];

  node_54 -> node_56 [label = "tuple", dir = back];
  node_53 [label = "Compare [53@52]"];

  node_48 -> node_53 [label = "int", dir = back];
  node_49 -> node_53 [label = "int", dir = back];
  node_54 [label = "Cond (2) [54@52]"];

  node_53 -> node_54 [label = "condition", dir = back];
  node_55 [label = "Proj (exe(1)) [55@52]"];

  node_54 -> node_55 [label = "tuple", dir = back];
  } /* block node_52 */

  subgraph "cluster_node_60"
  { /* block node_60 */
  label = "";
  node_60 [label = "Block [60]"];
  node_61 [label = "Return [61@60]"];

  node_50 -> node_61 [label = "mem", dir = back];
  node_49 -> node_61 [label = "int", dir = back];
  } /* block node_60 */

  subgraph "cluster_node_44"
  { /* block node_44 */
  label = "";
  node_44 [label = "Block [44]"];
  node_46 [label = "End [46@44]"];

  } /* block node_44 */

  node_56 -> node_60 [label = "exe", dir = back];
  node_51 -> node_52 [label = "exe", dir = back];
  node_55 -> node_57 [label = "exe", dir = back];
  node_58 -> node_44 [label = "exe", dir = back];
  node_61 -> node_44 [label = "exe", dir = back];
} /* Graph "If.try_if_then" */
</pre
				>
				<pre id="xdot">
// Difficulty: Easy
// Dot graph language.
// See http://www.rise4fun.com/Agl
return {
  // Set defaultToken to invalid to see what you do not tokenize yet
  // defaultToken: 'invalid',

  keywords: [
    'strict','graph','digraph','node','edge','subgraph','rank','abstract',
    'n','ne','e','se','s','sw','w','nw','c','_',
    '-&gt;',':','=',',',
  ],

  builtins: [
    'rank','rankdir','ranksep','size','ratio',
    'label','headlabel','taillabel',
    'arrowhead','samehead','samearrowhead',
    'arrowtail','sametail','samearrowtail','arrowsize',
    'labeldistance', 'labelangle', 'labelfontsize',
    'dir','width','height','angle',
    'fontsize','fontcolor', 'same','weight','color',
    'bgcolor','style','shape','fillcolor','nodesep','id',
  ],

  attributes: [
    'doublecircle','circle','diamond','box','point','ellipse','record',
    'inv','invdot','dot','dashed','dotted','filled','back','forward',
  ],

  // we include these common regular expressions
  symbols:  /[=&gt;&lt;!~?:&amp;|+\-*\/\^%]+/,


  // The main tokenizer for our languages
  tokenizer: {
    root: [
      // identifiers and keywords
      [/[a-zA-Z_\x80-\xFF][\w\x80-\xFF]*/, {
          cases: { '@keywords': 'keyword',
                   '@builtins': 'predefined',
                   '@attributes': 'constructor',
                   '@default': 'identifier' } }],

      // whitespace
      { include: '@whitespace' },

      // html identifiers
      [/&lt;(?!@symbols)/, { token: 'string.html.quote', bracket: '@open', next: 'html' } ],

      // delimiters and operators
      [/[{}()\[\]]/, '@brackets'],
      [/@symbols/, { cases: { '@keywords': 'keyword',
                              '@default' : 'operator' } } ],

      // delimiter
      [/[;,]/, 'delimiter'],

      // numbers
      [/\d*\.\d+([eE][\-+]?\d+)?/, 'number.float'],
      [/0[xX][0-9a-fA-F]+/, 'number.hex'],
      [/\d+/, 'number'],

      // strings
      [/"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/"/,  { token: 'string.quote', bracket: '@open', next: '@string' } ],
    ],

    comment: [
      [/[^\/*]+/, 'comment' ],
      [/\/\*/,    'comment', '@push' ],    // nested comment
      ["\\*/",    'comment', '@pop'  ],
      [/[\/*]/,   'comment' ]
    ],

    html: [
      [/[^&lt;&gt;&amp;]+/,   'string.html'],
      [/&amp;\w+;/,     'string.html.escape' ],
      [/&amp;/,         'string.html'],
      [/&lt;/,         { token: 'string.html.quote', bracket: '@open', next: '@push' } ], //nested bracket
      [/&gt;/,         { token: 'string.html.quote', bracket: '@close', next: '@pop' } ],
    ],

    string: [
      [/[^\\"&amp;]+/,  'string'],
      [/\\"/,       'string.escape'],
      [/&amp;\w+;/,     'string.escape'],
      [/[\\&amp;]/,     'string'],
      [/"/,         { token: 'string.quote', bracket: '@close', next: '@pop' } ]
    ],

    whitespace: [
      [/[ \t\r\n]+/, 'white'],
      [/\/\*/,       'comment', '@comment' ],
      [/\/\/.*$/,    'comment'],
      [/#.*$/,       'comment'],
    ],
  },
};
</pre
				>

				<pre id="csharp-sample">
// CSharp 4.0 ray-tracer sample by Luke Hoban
using System.Drawing;
using System.Linq;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Windows.Forms;

namespace RayTracer {
    public class RayTracer {

        private int screenWidth;
        private int screenHeight;
        private const int MaxDepth = 5;

        public Action&lt;int, int, System.Drawing.Color> setPixel;

        public RayTracer(int screenWidth, int screenHeight, Action&lt;int,int, System.Drawing.Color> setPixel) {
            this.screenWidth = screenWidth;
            this.screenHeight = screenHeight;
            this.setPixel = setPixel;
        }

        private IEnumerable&lt;ISect> Intersections(Ray ray, Scene scene)
        {
            return scene.Things
                        .Select(obj => obj.Intersect(ray))
                        .Where(inter => inter != null)
                        .OrderBy(inter => inter.Dist);
        }

        private double TestRay(Ray ray, Scene scene) {
            var isects = Intersections(ray, scene);
            ISect isect = isects.FirstOrDefault();
            if (isect == null)
                return 0;
            return isect.Dist;
        }

        private Color TraceRay(Ray ray, Scene scene, int depth) {
            var isects = Intersections(ray, scene);
            ISect isect = isects.FirstOrDefault();
            if (isect == null)
                return Color.Background;
            return Shade(isect, scene, depth);
        }

        private Color GetNaturalColor(SceneObject thing, Vector pos, Vector norm, Vector rd, Scene scene) {
            Color ret = Color.Make(0, 0, 0);
            foreach (Light light in scene.Lights) {
                Vector ldis = Vector.Minus(light.Pos, pos);
                Vector livec = Vector.Norm(ldis);
                double neatIsect = TestRay(new Ray() { Start = pos, Dir = livec }, scene);
                bool isInShadow = !((neatIsect > Vector.Mag(ldis)) || (neatIsect == 0));
                if (!isInShadow) {
                    double illum = Vector.Dot(livec, norm);
                    Color lcolor = illum > 0 ? Color.Times(illum, light.Color) : Color.Make(0, 0, 0);
                    double specular = Vector.Dot(livec, Vector.Norm(rd));
                    Color scolor = specular > 0 ? Color.Times(Math.Pow(specular, thing.Surface.Roughness), light.Color) : Color.Make(0, 0, 0);
                    ret = Color.Plus(ret, Color.Plus(Color.Times(thing.Surface.Diffuse(pos), lcolor),
                                                     Color.Times(thing.Surface.Specular(pos), scolor)));
                }
            }
            return ret;
        }

        private Color GetReflectionColor(SceneObject thing, Vector pos, Vector norm, Vector rd, Scene scene, int depth) {
            return Color.Times(thing.Surface.Reflect(pos), TraceRay(new Ray() { Start = pos, Dir = rd }, scene, depth + 1));
        }

        private Color Shade(ISect isect, Scene scene, int depth) {
            var d = isect.Ray.Dir;
            var pos = Vector.Plus(Vector.Times(isect.Dist, isect.Ray.Dir), isect.Ray.Start);
            var normal = isect.Thing.Normal(pos);
            var reflectDir = Vector.Minus(d, Vector.Times(2 * Vector.Dot(normal, d), normal));
            Color ret = Color.DefaultColor;
            ret = Color.Plus(ret, GetNaturalColor(isect.Thing, pos, normal, reflectDir, scene));
            if (depth >= MaxDepth) {
                return Color.Plus(ret, Color.Make(.5, .5, .5));
            }
            return Color.Plus(ret, GetReflectionColor(isect.Thing, Vector.Plus(pos, Vector.Times(.001, reflectDir)), normal, reflectDir, scene, depth));
        }

        private double RecenterX(double x) {
            return (x - (screenWidth / 2.0)) / (2.0 * screenWidth);
        }
        private double RecenterY(double y) {
            return -(y - (screenHeight / 2.0)) / (2.0 * screenHeight);
        }

        private Vector GetPoint(double x, double y, Camera camera) {
            return Vector.Norm(Vector.Plus(camera.Forward, Vector.Plus(Vector.Times(RecenterX(x), camera.Right),
                                                                       Vector.Times(RecenterY(y), camera.Up))));
        }

        internal void Render(Scene scene) {
            for (int y = 0; y &lt; screenHeight; y++)
            {
                for (int x = 0; x &lt; screenWidth; x++)
                {
                    Color color = TraceRay(new Ray() { Start = scene.Camera.Pos, Dir = GetPoint(x, y, scene.Camera) }, scene, 0);
                    setPixel(x, y, color.ToDrawingColor());
                }
            }
        }

        internal readonly Scene DefaultScene =
            new Scene() {
                    Things = new SceneObject[] {
                                new Plane() {
                                    Norm = Vector.Make(0,1,0),
                                    Offset = 0,
                                    Surface = Surfaces.CheckerBoard
                                },
                                new Sphere() {
                                    Center = Vector.Make(0,1,0),
                                    Radius = 1,
                                    Surface = Surfaces.Shiny
                                },
                                new Sphere() {
                                    Center = Vector.Make(-1,.5,1.5),
                                    Radius = .5,
                                    Surface = Surfaces.Shiny
                                }},
                    Lights = new Light[] {
                                new Light() {
                                    Pos = Vector.Make(-2,2.5,0),
                                    Color = Color.Make(.49,.07,.07)
                                },
                                new Light() {
                                    Pos = Vector.Make(1.5,2.5,1.5),
                                    Color = Color.Make(.07,.07,.49)
                                },
                                new Light() {
                                    Pos = Vector.Make(1.5,2.5,-1.5),
                                    Color = Color.Make(.07,.49,.071)
                                },
                                new Light() {
                                    Pos = Vector.Make(0,3.5,0),
                                    Color = Color.Make(.21,.21,.35)
                                }},
                    Camera = Camera.Create(Vector.Make(3,2,4), Vector.Make(-1,.5,0))
                };
    }

    static class Surfaces {
        // Only works with X-Z plane.
        public static readonly Surface CheckerBoard  =
            new Surface() {
                Diffuse = pos => ((Math.Floor(pos.Z) + Math.Floor(pos.X)) % 2 != 0)
                                    ? Color.Make(1,1,1)
                                    : Color.Make(0,0,0),
                Specular = pos => Color.Make(1,1,1),
                Reflect = pos => ((Math.Floor(pos.Z) + Math.Floor(pos.X)) % 2 != 0)
                                    ? .1
                                    : .7,
                Roughness = 150
            };


        public static readonly Surface Shiny  =
            new Surface() {
                Diffuse = pos => Color.Make(1,1,1),
                Specular = pos => Color.Make(.5,.5,.5),
                Reflect = pos => .6,
                Roughness = 50
            };
    }

    class Vector {
        public double X;
        public double Y;
        public double Z;

        public Vector(double x, double y, double z) { X = x; Y = y; Z = z; }
        public Vector(string str) {
            string[] nums = str.Split(',');
            if (nums.Length != 3) throw new ArgumentException();
            X = double.Parse(nums[0]);
            Y = double.Parse(nums[1]);
            Z = double.Parse(nums[2]);
        }
        public static Vector Make(double x, double y, double z) { return new Vector(x, y, z); }
        public static Vector Times(double n, Vector v) {
            return new Vector(v.X * n, v.Y * n, v.Z * n);
        }
        public static Vector Minus(Vector v1, Vector v2) {
            return new Vector(v1.X - v2.X, v1.Y - v2.Y, v1.Z - v2.Z);
        }
        public static Vector Plus(Vector v1, Vector v2) {
            return new Vector(v1.X + v2.X, v1.Y + v2.Y, v1.Z + v2.Z);
        }
        public static double Dot(Vector v1, Vector v2) {
            return (v1.X * v2.X) + (v1.Y * v2.Y) + (v1.Z * v2.Z);
        }
        public static double Mag(Vector v) { return Math.Sqrt(Dot(v, v)); }
        public static Vector Norm(Vector v) {
            double mag = Mag(v);
            double div = mag == 0 ? double.PositiveInfinity : 1 / mag;
            return Times(div, v);
        }
        public static Vector Cross(Vector v1, Vector v2) {
            return new Vector(((v1.Y * v2.Z) - (v1.Z * v2.Y)),
                              ((v1.Z * v2.X) - (v1.X * v2.Z)),
                              ((v1.X * v2.Y) - (v1.Y * v2.X)));
        }
        public static bool Equals(Vector v1, Vector v2) {
            return (v1.X == v2.X) &amp;&amp; (v1.Y == v2.Y) &amp;&amp; (v1.Z == v2.Z);
        }
    }

    public class Color {
        public double R;
        public double G;
        public double B;

        public Color(double r, double g, double b) { R = r; G = g; B = b; }
        public Color(string str) {
            string[] nums = str.Split(',');
            if (nums.Length != 3) throw new ArgumentException();
            R = double.Parse(nums[0]);
            G = double.Parse(nums[1]);
            B = double.Parse(nums[2]);
        }

        public static Color Make(double r, double g, double b) { return new Color(r, g, b); }

        public static Color Times(double n, Color v) {
            return new Color(n * v.R, n * v.G, n * v.B);
        }
        public static Color Times(Color v1, Color v2) {
            return new Color(v1.R * v2.R, v1.G * v2.G,v1.B * v2.B);
        }

        public static Color Plus(Color v1, Color v2) {
            return new Color(v1.R + v2.R, v1.G + v2.G,v1.B + v2.B);
        }
        public static Color Minus(Color v1, Color v2) {
            return new Color(v1.R - v2.R, v1.G - v2.G,v1.B - v2.B);
        }

        public static readonly Color Background = Make(0, 0, 0);
        public static readonly Color DefaultColor = Make(0, 0, 0);

        public double Legalize(double d) {
            return d > 1 ? 1 : d;
        }

        internal System.Drawing.Color ToDrawingColor() {
            return System.Drawing.Color.FromArgb((int)(Legalize(R) * 255), (int)(Legalize(G) * 255), (int)(Legalize(B) * 255));
        }

    }

    class Ray {
        public Vector Start;
        public Vector Dir;
    }

    class ISect {
        public SceneObject Thing;
        public Ray Ray;
        public double Dist;
    }

    class Surface {
        public Func&lt;Vector, Color> Diffuse;
        public Func&lt;Vector, Color> Specular;
        public Func&lt;Vector, double> Reflect;
        public double Roughness;
    }

    class Camera {
        public Vector Pos;
        public Vector Forward;
        public Vector Up;
        public Vector Right;

        public static Camera Create(Vector pos, Vector lookAt) {
            Vector forward = Vector.Norm(Vector.Minus(lookAt, pos));
            Vector down = new Vector(0, -1, 0);
            Vector right = Vector.Times(1.5, Vector.Norm(Vector.Cross(forward, down)));
            Vector up = Vector.Times(1.5, Vector.Norm(Vector.Cross(forward, right)));

            return new Camera() { Pos = pos, Forward = forward, Up = up, Right = right };
        }
    }

    class Light {
        public Vector Pos;
        public Color Color;
    }

    abstract class SceneObject {
        public Surface Surface;
        public abstract ISect Intersect(Ray ray);
        public abstract Vector Normal(Vector pos);
    }

    class Sphere : SceneObject {
        public Vector Center;
        public double Radius;

        public override ISect Intersect(Ray ray) {
            Vector eo = Vector.Minus(Center, ray.Start);
            double v = Vector.Dot(eo, ray.Dir);
            double dist;
            if (v &lt; 0) {
                dist = 0;
            }
            else {
                double disc = Math.Pow(Radius,2) - (Vector.Dot(eo, eo) - Math.Pow(v,2));
                dist = disc &lt; 0 ? 0 : v - Math.Sqrt(disc);
            }
            if (dist == 0) return null;
            return new ISect() {
                Thing = this,
                Ray = ray,
                Dist = dist};
        }

        public override Vector Normal(Vector pos) {
            return Vector.Norm(Vector.Minus(pos, Center));
        }
    }

    class Plane : SceneObject {
        public Vector Norm;
        public double Offset;

        public override ISect Intersect(Ray ray) {
            double denom = Vector.Dot(Norm, ray.Dir);
            if (denom > 0) return null;
            return new ISect() {
                Thing = this,
                Ray = ray,
                Dist = (Vector.Dot(Norm, ray.Start) + Offset) / (-denom)};
        }

        public override Vector Normal(Vector pos) {
            return Norm;
        }
    }

    class Scene {
        public SceneObject[] Things;
        public Light[] Lights;
        public Camera Camera;

        public IEnumerable&lt;ISect> Intersect(Ray r) {
            return from thing in Things
                   select thing.Intersect(r);
        }
    }

    public delegate void Action&lt;T,U,V>(T t, U u, V v);

    public partial class RayTracerForm : Form
    {
        Bitmap bitmap;
        PictureBox pictureBox;
        const int width = 600;
        const int height = 600;

        public RayTracerForm()
        {
            bitmap = new Bitmap(width,height);

            pictureBox = new PictureBox();
            pictureBox.Dock = DockStyle.Fill;
            pictureBox.SizeMode = PictureBoxSizeMode.StretchImage;
            pictureBox.Image = bitmap;

            ClientSize = new System.Drawing.Size(width, height + 24);
            Controls.Add(pictureBox);
            Text = "Ray Tracer";
            Load += RayTracerForm_Load;

            Show();
        }

        private void RayTracerForm_Load(object sender, EventArgs e)
        {
            this.Show();
            RayTracer rayTracer = new RayTracer(width, height, (int x, int y, System.Drawing.Color color) =>
                                                               {
                                                                   bitmap.SetPixel(x, y, color);
                                                                   if (x == 0) pictureBox.Refresh();
                                                               });
            rayTracer.Render(rayTracer.DefaultScene);
            pictureBox.Invalidate();

        }

        [STAThread]
        static void Main() {
            Application.EnableVisualStyles();

            Application.Run(new RayTracerForm());
        }
    }
}
</pre
				>
				<pre id="csharp">
// Difficulty: Moderate
// CSharp language definition
// Takes special care to color types and namespaces nicely.
// (note: this can't be done completely accurately though on a lexical level,
//  but we are getting quite close :-) )
//
// Todo: support unicode identifiers
// Todo: special color for documentation comments and attributes
return {
	defaultToken: '',
	tokenPostfix: '.cs',

	brackets: [
		{ open: '{', close: '}', token: 'delimiter.curly' },
		{ open: '[', close: ']', token: 'delimiter.square' },
		{ open: '(', close: ')', token: 'delimiter.parenthesis' },
		{ open: '&lt;', close: '&gt;', token: 'delimiter.angle' }
	],

	keywords: [
		'extern', 'alias', 'using', 'bool', 'decimal', 'sbyte', 'byte', 'short',
		'ushort', 'int', 'uint', 'long', 'ulong', 'char', 'float', 'double',
		'object', 'dynamic', 'string', 'assembly', 'is', 'as', 'ref',
		'out', 'this', 'base', 'new', 'typeof', 'void', 'checked', 'unchecked',
		'default', 'delegate', 'var', 'const', 'if', 'else', 'switch', 'case',
		'while', 'do', 'for', 'foreach', 'in', 'break', 'continue', 'goto',
		'return', 'throw', 'try', 'catch', 'finally', 'lock', 'yield', 'from',
		'let', 'where', 'join', 'on', 'equals', 'into', 'orderby', 'ascending',
		'descending', 'select', 'group', 'by', 'namespace', 'partial', 'class',
		'field', 'event', 'method', 'param', 'property', 'public', 'protected',
		'internal', 'private', 'abstract', 'sealed', 'static', 'struct', 'readonly',
		'volatile', 'virtual', 'override', 'params', 'get', 'set', 'add', 'remove',
		'operator', 'true', 'false', 'implicit', 'explicit', 'interface', 'enum',
		'null', 'async', 'await', 'fixed', 'sizeof', 'stackalloc', 'unsafe', 'nameof',
		'when'
	],

	namespaceFollows: [
		'namespace', 'using',
	],

	parenFollows: [
		'if', 'for', 'while', 'switch', 'foreach', 'using', 'catch', 'when'
	],

	operators: [
		'=', '??', '||', '&amp;&amp;', '|', '^', '&amp;', '==', '!=', '&lt;=', '&gt;=', '&lt;&lt;',
		'+', '-', '*', '/', '%', '!', '~', '++', '--', '+=',
		'-=', '*=', '/=', '%=', '&amp;=', '|=', '^=', '&lt;&lt;=', '&gt;&gt;=', '&gt;&gt;', '=&gt;'
	],

	symbols: /[=&gt;&lt;!~?:&amp;|+\-*\/\^%]+/,

	// escape sequences
	escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,

	// The main tokenizer for our languages
	tokenizer: {
		root: [

			// identifiers and keywords
			[/\@?[a-zA-Z_]\w*/, {
				cases: {
					'@namespaceFollows': { token: 'keyword.$0', next: '@namespace' },
					'@keywords': { token: 'keyword.$0', next: '@qualified' },
					'@default': { token: 'identifier', next: '@qualified' }
				}
			}],

			// whitespace
			{ include: '@whitespace' },

			// delimiters and operators
			[/}/, {
				cases: {
					'$S2==interpolatedstring': { token: 'string.quote', next: '@pop' },
					'$S2==litinterpstring': { token: 'string.quote', next: '@pop' },
					'@default': '@brackets'
				}
			}],
			[/[{}()\[\]]/, '@brackets'],
			[/[&lt;&gt;](?!@symbols)/, '@brackets'],
			[/@symbols/, {
				cases: {
					'@operators': 'delimiter',
					'@default': ''
				}
			}],


			// numbers
			[/[0-9_]*\.[0-9_]+([eE][\-+]?\d+)?[fFdD]?/, 'number.float'],
			[/0[xX][0-9a-fA-F_]+/, 'number.hex'],
			[/0[bB][01_]+/, 'number.hex'], // binary: use same theme style as hex
			[/[0-9_]+/, 'number'],

			// delimiter: after number because of .\d floats
			[/[;,.]/, 'delimiter'],

			// strings
			[/"([^"\\]|\\.)*$/, 'string.invalid'],  // non-teminated string
			[/"/, { token: 'string.quote', next: '@string' }],
			[/\$\@"/, { token: 'string.quote', next: '@litinterpstring' }],
			[/\@"/, { token: 'string.quote', next: '@litstring' }],
			[/\$"/, { token: 'string.quote', next: '@interpolatedstring' }],

			// characters
			[/'[^\\']'/, 'string'],
			[/(')(@escapes)(')/, ['string', 'string.escape', 'string']],
			[/'/, 'string.invalid']
		],

		qualified: [
			[/[a-zA-Z_][\w]*/, {
				cases: {
					'@keywords': { token: 'keyword.$0' },
					'@default': 'identifier'
				}
			}],
			[/\./, 'delimiter'],
			['', '', '@pop'],
		],

		namespace: [
			{ include: '@whitespace' },
			[/[A-Z]\w*/, 'namespace'],
			[/[\.=]/, 'delimiter'],
			['', '', '@pop'],
		],

		comment: [
			[/[^\/*]+/, 'comment'],
			// [/\/\*/,    'comment', '@push' ],    // no nested comments :-(
			['\\*/', 'comment', '@pop'],
			[/[\/*]/, 'comment']
		],

		string: [
			[/[^\\"]+/, 'string'],
			[/@escapes/, 'string.escape'],
			[/\\./, 'string.escape.invalid'],
			[/"/, { token: 'string.quote', next: '@pop' }]
		],

		litstring: [
			[/[^"]+/, 'string'],
			[/""/, 'string.escape'],
			[/"/, { token: 'string.quote', next: '@pop' }]
		],

		litinterpstring: [
			[/[^"{]+/, 'string'],
			[/""/, 'string.escape'],
			[/{{/, 'string.escape'],
			[/}}/, 'string.escape'],
			[/{/, { token: 'string.quote', next: 'root.litinterpstring' }],
			[/"/, { token: 'string.quote', next: '@pop' }]
		],

		interpolatedstring: [
			[/[^\\"{]+/, 'string'],
			[/@escapes/, 'string.escape'],
			[/\\./, 'string.escape.invalid'],
			[/{{/, 'string.escape'],
			[/}}/, 'string.escape'],
			[/{/, { token: 'string.quote', next: 'root.interpolatedstring' }],
			[/"/, { token: 'string.quote', next: '@pop' }]
		],

		whitespace: [
			[/^[ \t\v\f]*#((r)|(load))(?=\s)/, 'directive.csx'],
			[/^[ \t\v\f]*#\w.*$/, 'namespace.cpp'],
			[/[ \t\v\f\r\n]+/, ''],
			[/\/\*/, 'comment', '@comment'],
			[/\/\/.*$/, 'comment'],
		],
	},
};
</pre
				>

				<pre id="chalice-sample">
// This example shows a use of a channel.  Properties of the messages
// passed along the channel, as well as permissions and channel credits,
// are specified in the channel's "where" clause.

channel NumberStream(x: int) where 2 &lt;= x ==> credit(this);

class Sieve {
  method Counter(n: NumberStream, to: int)  // sends the plurals along n
    requires rd(n.mu) &amp;&amp; credit(n,-1) &amp;&amp; 0 &lt;= to;
  {
    var i := 2;
    while (i &lt; to)
      invariant rd(n.mu);
      invariant 2 &lt;= i;
      invariant credit(n, -1)
    {
      send n(i);
      i := i + 1;
    }
    send n(-1);
  }

  method Filter(prime: int, r: NumberStream, s: NumberStream)
    requires 2 &lt;= prime;
    requires rd(r.mu) &amp;&amp; waitlevel &lt;&lt; r.mu;
    requires rd(s.mu) &amp;&amp; s.mu &lt;&lt; r.mu &amp;&amp; credit(r) &amp;&amp; credit(s, -1);
  {
    receive x := r;
    while (2 &lt;= x)
      invariant rd(r.mu) &amp;&amp; rd(s.mu) &amp;&amp; s &lt;&lt; r &amp;&amp; waitlevel &lt;&lt; r.mu;
      invariant 2&lt;= x ==> credit(r);
      invariant credit(s, -1);
    {
      if (x % prime != 0) {  // suppress multiples of prime
        send s(x);
      }
      receive x := r;

    }
    send s(-1);
  }

  method Start()
  {
    var ch := new NumberStream;
    fork Counter(ch, 101);
    var p: int;
    receive p := ch;
    while (2 &lt;= p)
      invariant ch != null;
      invariant 2 &lt;= p ==> credit(ch, 1);
      invariant rd*(ch.mu) &amp;&amp; waitlevel &lt;&lt; ch.mu;
    {
      // print p--it's a prime!
      var cp := new ChalicePrint;  call cp.Int(p);

      var n := new NumberStream between waitlevel and ch;
      fork Filter(p, ch, n);
      ch := n;
      receive p := ch;
    }
  }
}

external class ChalicePrint {
  method Int(x: int) { }
}
</pre
				>

				<pre id="chalice">
// Difficulty: "Easy"
// Language definition sample for the Chalice language.
// See 'http://rise4fun.com/Chalice'.
return {
  keywords: [
    'class','ghost','var','const','method','channel','condition',
    'assert','assume','new','this','reorder',
    'between','and','above','below','share','unshare','acquire','release','downgrade',

    'call','if','else','while','lockchange',
    'returns','where',
    'false','true','null',
    'waitlevel','lockbottom',
    'module','external',
    'predicate','function',
    'forall','exists',
    'nil','result','eval','token',
    'unlimited',
    'refines','transforms','replaces','by','spec',
  ],

  builtins: [
    'lock','fork','join','rd','acc','credit','holds','old','assigned',
    'send','receive',
    'ite','fold','unfold','unfolding','in',
    'wait','signal',
  ],

  verifyKeywords: [
   'requires','ensures','free','invariant'
  ],

  types: [
   'bool','int','string','seq'
  ],

  brackets: [
    ['{','}','delimiter.curly'],
    ['[',']','delimiter.square'],
    ['(',')','delimiter.parenthesis']
  ],

  // Chalice uses C# style strings
  escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,

  tokenizer: {
    root: [
      // identifiers
      [/array([2-9]\d*|1\d+)/, 'type.keyword' ],
      [/[a-zA-Z'_\?\\][\w'\?\\]*/, { cases: {'@keywords': 'keyword',
                                             '@verifyKeywords': 'constructor.identifier',
                                             '@builtins': 'keyword',
                                             '@types'   : 'type.keyword',
                                             '@default' : 'identifier' }}],
      [':=','keyword'],

      // whitespace
      { include: '@whitespace' },

      [/[{}()\[\]]/, '@brackets'],
      [/[;,]/, 'delimiter'],

      // literals
      [/[0-9]+/, 'number'],

      // strings
      [/"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/"/,  'string', '@string' ],
    ],

    whitespace: [
      [/[ \t\r\n]+/, 'white'],
      [/\/\*/,       'comment', '@comment' ],
      [/\/\/.*$/,    'comment'],
    ],

    comment: [
      [/[^\/*]+/, 'comment' ],
      [/\/\*/, 'comment', '@push' ],    // nested comment
      ["\\*/",    'comment', '@pop'  ],
      [/[\/*]/,   'comment' ]
    ],

    string: [
      [/[^\\"]+/,  'string'],
      [/@escapes/, 'string.escape'],
      [/\\./,      'string.escape.invalid'],
      [/"/,  'string', '@pop' ]
    ],
  }
};
</pre
				>

				<pre id="specsharp-sample">
// This example shows many of the features of Spec#, including pre-
// and postcondition of methods and object invariants.  The basic
// idea in the example is to implement a "chunker", which returns
// successive portions of a given string.  The main work is done
// in the NextChunk() method.

// For a full demo showing this example, check out the "The Chunker"
// episode on Verification Corner
// (http://research.microsoft.com/verificationcorner)

public class Chunker
{
  string src;
  int ChunkSize;
  invariant 0 &lt;= ChunkSize;
  int n;  // the number of characters returned so far
  invariant 0 &lt;= n;

  public string NextChunk()
    ensures result.Length &lt;= ChunkSize;
  {
    string s;
    if (n + ChunkSize &lt;= src.Length) {
      s = src.Substring(n, ChunkSize);
    } else {
      s = src.Substring(n);
    }
    return s;
  }

  public Chunker(string source, int chunkSize)
  {
    src = source;
    ChunkSize = chunkSize;
    n = 0;
  }
}
</pre
				>

				<pre id="specsharp">
// Difficulty: Moderate
// SpecSharp language definition. This is an extension of the C# language definition.
// See: http://rise4fun.com/SpecSharp for more information
//
// Takes special care to color types and namespaces nicely.
// (note: this can't be done completely accurately though on a lexical level,
//  but we are getting quite close :-) )
//
// Todo: support unicode identifiers
// Todo: special color for documentation comments and attributes
return {
  keywords: [
    'extern', 'alias', 'using', 'bool', 'decimal', 'sbyte', 'byte', 'short',
    'ushort', 'int', 'uint', 'long', 'ulong', 'char', 'float', 'double',
    'object', 'dynamic', 'string', 'assembly', 'module', 'is', 'as', 'ref',
    'out', 'this', 'base', 'new', 'typeof', 'void', 'checked', 'unchecked',
    'default', 'delegate', 'var', 'const', 'if', 'else', 'switch', 'case',
    'while', 'do', 'for', 'foreach', 'in', 'break', 'continue', 'goto',
    'return', 'throw', 'try', 'catch', 'finally', 'lock', 'yield', 'from',
    'let', 'where', 'join', 'on', 'equals', 'into', 'orderby', 'ascending',
    'descending', 'select', 'group', 'by', 'namespace', 'partial', 'class',
    'field', 'event', 'method', 'param', 'property', 'public', 'protected',
    'internal', 'private', 'abstract', 'sealed', 'static', 'struct', 'readonly',
    'volatile', 'virtual', 'override', 'params', 'get', 'set', 'add', 'remove',
    'operator', 'true', 'false', 'implicit', 'explicit', 'interface', 'enum',
    'null',
    '=',':',
    'expose', 'assert', 'assume',
    'additive', 'model', 'throws',
    'forall', 'exists', 'unique', 'count', 'max', 'min', 'product', 'sum',
    'result'
  ],

  verifyKeywords: [
    'requires', 'modifies', 'ensures', 'otherwise', 'satisfies', 'witness', 'invariant',
  ],

  typeKeywords: [
    'bool', 'byte', 'char', 'decimal', 'double', 'fixed', 'float',
    'int', 'long','object','sbyte','short','string','uint','ulong',
    'ushort','void'
  ],

  keywordInType: [
    'struct','new','where','class'
  ],

  typeFollows: [
    'as', 'class', 'interface', 'struct', 'enum', 'new','where',
    ':',
  ],

  namespaceFollows: [
    'namespace', 'using',
  ],

  operators: [
    '??', '||', '&amp;&amp;', '|', '^', '&amp;', '==', '!=', '&lt;=', '&gt;=', '&lt;&lt;',
    '+', '-', '*', '/', '%', '!', '~', '++', '--','+=',
    '-=', '*=', '/=', '%=', '&amp;=', '|=', '^=', '&lt;&lt;=', '&gt;&gt;=', '&gt;&gt;', '=&gt;'
  ],

  symbols:  /[=&gt;&lt;!~?:&amp;|+\-*\/\^%]+/,

  // escape sequences
  escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,

  // The main tokenizer for our languages
  tokenizer: {
    root: [
      // Try to show type names nicely: for parameters: Type name
      [/[A-Z][\w]*(?=[\.\w]*(\s|\/\*!\*\/)+\w)/, 'type.identifier' ],

      // Generic types List&lt;int&gt;.
      // Unfortunately, colors explicit nested generic method instantiation as Method&lt;List&lt;int&gt;&gt;(x) wrongly
      [/([A-Z][\w]*[\.\w]*)(&lt;)(?![^&gt;]+&gt;\s*(?:\(|$))/, ['type.identifier', { token: '@brackets', next: '@type' } ]],
      [/([A-Z][\w]*[\.\w]*)(&lt;)/, ['identifier', { token: '@brackets', next: '@type' } ]],

      // These take care of 'System.Console.WriteLine'.
      // These two rules are not 100% right: if a non-qualified field has an uppercase name
      // it colors it as a type.. but you could use this.Field to circumenvent this.
      [/[A-Z][\w]*(?=\.[A-Z])/, 'type.identifier' ],
      [/[A-Z][\w]*(?=\.[a-z_])/, 'type.identifier', '@qualified' ],

      // identifiers and keywords
      [/[a-zA-Z_]\w*/, { cases: {'@typeFollows': { token: 'keyword', next: '@type' },
                                 '@namespaceFollows': { token: 'keyword', next: '@namespace' },
                                 '@typeKeywords': { token: 'type.identifier', next: '@qualified' },
                                 '@keywords': { token: 'keyword', next: '@qualified' },
                                 '@verifyKeywords': { token: 'constructor', next: '@qualified' },
                                 '@default': { token: 'identifier', next: '@qualified' } } }],

      // whitespace
      { include: '@whitespace' },

      // delimiters and operators
      [/[{}()\[\]]/, '@brackets'],
      [/[&lt;&gt;](?!@symbols)/, '@brackets'],
      [/@symbols/, { cases: { '@operators': 'operator',
                              '@default'  : '' } } ],

      // literal string
      [/@"/, { token: 'string.quote', bracket: '@open', next: '@litstring' } ],

      // numbers
      [/\d*\.\d+([eE][\-+]?\d+)?/, 'number.float'],
      [/0[xX][0-9a-fA-F]+/, 'number.hex'],
      [/\d+/, 'number'],

      // delimiter: after number because of .\d floats
      [/[;,.]/, 'delimiter'],

      // strings
      [/"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/"/,  { token: 'string.quote', bracket: '@open', next: '@string' } ],

      // characters
      [/'[^\\']'/, 'string'],
      [/(')(@escapes)(')/, ['string','string.escape','string']],
      [/'/, 'string.invalid']
    ],

    qualified: [
      [/[a-zA-Z_][\w]*/, { cases: { '@typeFollows': { token: 'keyword', next: '@type' },
                                    '@typeKeywords': 'type.identifier',
                                    '@keywords': 'keyword',
                                    '@verifyKeywords': 'constructor',
                                    '@default': 'identifier' } }],
      [/\./, 'delimiter'],
      ['','','@pop'],
    ],

    type: [
      { include: '@whitespace' },
      [/[A-Z]\w*/, 'type.identifier'],
      // identifiers and keywords
      [/[a-zA-Z_]\w*/, { cases: {'@typeKeywords': 'type.identifier',
                                 '@keywordInType': 'keyword',
                                 '@keywords': {token: '@rematch', next: '@popall'},
                                 '@verifyKeywords': {token: '@rematch', next: '@popall'},
                                 '@default': 'type.identifier' } }],
      [/[&lt;]/, '@brackets', '@type_nested' ],
      [/[&gt;]/, '@brackets', '@pop' ],
      [/[\.,:]/, { cases: { '@keywords': 'keyword',
                            '@verifyKeywords': 'constructor',
                            '@default': 'delimiter' }}],
      ['','','@popall'], // catch all
    ],

    type_nested: [
      [/[&lt;]/, '@brackets', '@type_nested' ],
      { include: 'type' }
    ],

    namespace: [
      { include: '@whitespace' },
      [/[A-Z]\w*/, 'namespace'],
      [/[\.=]/, 'keyword'],
      ['','','@pop'],
    ],

    comment: [
      [/[^\/*]+/, 'comment' ],
      // [/\/\*/,    'comment', '@push' ],    // no nested comments :-(
      ["\\*/",    'comment', '@pop'  ],
      [/[\/*]/,   'comment' ]
    ],

    string: [
      [/[^\\"]+/,  'string'],
      [/@escapes/, 'string.escape'],
      [/\\./,      'string.escape.invalid'],
      [/"/,        { token: 'string.quote', bracket: '@close', next: '@pop' } ]
    ],

    litstring: [
      [/[^"]+/,    'string'],
      [/""/,       'string.escape'],
      [/"/,        { token: 'string.quote', bracket: '@close', next: '@pop' } ]
    ],

    whitespace: [
      [/^[ \t\v\f]*#\w.*$/, 'namespace.cpp' ],
      [/[ \t\v\f\r\n]+/, 'white'],
      [/\/\*/,       'comment', '@comment' ],
      [/\/\/.*$/,    'comment'],
    ],
  },
};</pre
				>

				<pre id="boogie-sample">
// The partition step of Quick Sort picks a 'pivot' element from a specified subsection
// of a given integer array.  It then partially sorts the elements of the array so that
// elements smaller than the pivot end up to the left of the pivot and elements larger
// than the pivot end up to the right of the pivot.  Finally, the index of the pivot is
// returned.
// The procedure below always picks the first element of the subregion as the pivot.
// The specification of the procedure talks about the ordering of the elements, but
// does not say anything about keeping the multiset of elements the same.

var A: [int]int;
const N: int;

procedure Partition(l: int, r: int) returns (result: int)
  requires 0 &lt;= l &amp;&amp; l+2 &lt;= r &amp;&amp; r &lt;= N;
  modifies A;
  ensures l &lt;= result &amp;&amp; result &lt; r;
  ensures (forall k: int, j: int :: l &lt;= k &amp;&amp; k &lt; result &amp;&amp; result &lt;= j &amp;&amp; j &lt; r  ==>  A[k] &lt;= A[j]);
  ensures (forall k: int :: l &lt;= k &amp;&amp; k &lt; result  ==>  A[k] &lt;= old(A)[l]);
  ensures (forall k: int :: result &lt;= k &amp;&amp; k &lt; r  ==>  old(A)[l] &lt;= A[k]);
{
  var pv, i, j, tmp: int;

  pv := A[l];
  i := l;
  j := r-1;
  // swap A[l] and A[j]
  tmp := A[l];
  A[l] := A[j];
  A[j] := tmp;
  goto LoopHead;

  // The following loop iterates while 'i &lt; j'.  In each iteration,
  // one of the three alternatives (A, B, or C) is chosen in such
  // a way that the assume statements will evaluate to true.
  LoopHead:
    // The following the assert statements give the loop invariant
    assert (forall k: int :: l &lt;= k &amp;&amp; k &lt; i  ==>  A[k] &lt;= pv);
    assert (forall k: int :: j &lt;= k &amp;&amp; k &lt; r  ==>  pv &lt;= A[k]);
    assert l &lt;= i &amp;&amp; i &lt;= j &amp;&amp; j &lt; r;
    goto A, B, C, exit;

  A:
    assume i &lt; j;
    assume A[i] &lt;= pv;
    i := i + 1;
    goto LoopHead;

  B:
    assume i &lt; j;
    assume pv &lt;= A[j-1];
    j := j - 1;
    goto LoopHead;

  C:
    assume i &lt; j;
    assume A[j-1] &lt; pv &amp;&amp; pv &lt; A[i];
    // swap A[j-1] and A[i]
    tmp := A[i];
    A[i] := A[j-1];
    A[j-1] := tmp;
    assert A[i] &lt; pv &amp;&amp; pv &lt; A[j-1];
    i := i + 1;
    j := j - 1;
    goto LoopHead;

  exit:
    assume i == j;
    result := i;
}
</pre
				>

				<pre id="boogie">
// Difficulty: "Easy"
// Language definition sample for the Boogie language.
// See 'http://rise4fun.com/Boogie'.
return {
  keywords: [
    'type','const','function','axiom','var','procedure','implementation',
    'returns',
    'assert','assume','break','call','then','else','havoc','if','goto','return','while',
    'old','forall','exists','lambda','cast',
    'false','true'
  ],

  verifyKeywords: [
    'where','requires','ensures','modifies','free','invariant',
    'unique','extends','complete'
  ],

  types: [
    'bool','int'
  ],

  escapes: '\\\\(?:[abfnrtv\\\\""\']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})',

  tokenizer: {
    root: [
      // identifiers
      ['bv(0|[1-9]\\d*)', 'type.keyword' ],
      [/\\?[a-zA-Z_'\~#\$\^\.\?\\`][\w_'\~#\$\^\.\?\\`]*(\s*:\s*$)?/,
        { cases: {'$1': 'constructor',
                  '@keywords': 'keyword',
                  '@verifyKeywords': 'constructor.identifier',
                  '@types'   : 'type.keyword',
                  '@default' : 'identifier' }}],
      [':=','keyword'],

      // whitespace
      { include: '@whitespace' },

      ['[\\{\\}\\(\\)\\[\\]]', '@brackets'],
      ['[;,]', 'delimiter'],

      // literals
      ['[0-9]+bv[0-9]+', 'number'],  // this is perhaps not so much a 'number' as it is a 'bitvector literal'
      ['[0-9]+', 'number'],
      ['""$', 'string.invalid'], // recover
      ['""', 'string', '@string' ],
    ],

    whitespace: [
      ['[ \\t\\r\\n]+', 'white'],
      ['/\\*', 'comment', '@comment' ],
      ['//.*', 'comment']
    ],

    comment: [
      ['[^/\\*]+', 'comment' ],
      ['/\\*',  'comment', '@push' ],
      ['\\*/',  'comment', '@pop'  ],
      ['[/\\*]', 'comment']
    ],

    string: [
      ['[^\\\\""]+$', 'string.invalid', '@pop'],  // recover on end of line
      ['@escapes$', 'string.escape.invalid', '@pop'], // more recovery
      ['[^\\\\""]+', 'string'],
      ['@escapes', 'string.escape'],
      ['""', 'string', '@pop' ]
    ]
  }
}
</pre
				>

				<pre id="formula-sample">
/*
  This Formula specificatin models a problem in graph theory. It tries to find
  a Eulerian walk within a specified graph. The problem is to find a walk through
  the graph with the following properties:

  - all edges in the graph must be used
  - every edge must be used only once

  A well known example of this problem is the so called German "Das-ist-das-Haus-vom-Nikolaus"
  problem, which is modeled within this file.
*/

domain EulerWay
{
  primitive BaseEdge ::= (x:PosInteger, y:PosInteger).
  primitive SolutionEdge ::= (pos:PosInteger, x : PosInteger, y : PosInteger).

  // Make sure we have used all BaseEdge terms in the solution
  usedBaseEdge ::= (x:PosInteger, y:PosInteger).
  usedBaseEdge(x,y) :- BaseEdge(x,y), SolutionEdge(_,x,y).
  usedBaseEdge(x,y) :- BaseEdge(x,y), SolutionEdge(_,y,x).
  unusedBaseEdge := BaseEdge(x,y), fail usedBaseEdge(x,y).

  // Make sure our index values are one based and not bigger than the number of base edges
  indexTooBig := SolutionEdge(x,_,_), x > count(BaseEdge(_,_)).

  // Make sure that no index is used twice
  doubleIndex := s1 is SolutionEdge, s2 is SolutionEdge, s1 != s2, s1.pos = s2.pos.

  // Exclude edges that don't line up
  //wrongSequence := SolutionEdge(x, Edge(_,b)), SolutionEdge(y, Edge(c,_)), y = x + 1, b != c.
  wrongSequence := SolutionEdge(pos1,_,y1), SolutionEdge(pos2,x2,_), pos2 = pos1 + 1, y1 != x2.

  // Avoid using edges twice
  doubleEdge := SolutionEdge(pos1,x,y), SolutionEdge(pos2,x,y), pos1 != pos2.

  // Exclude mirrors of already used edges
  mirrorEdge := SolutionEdge(_,x,y), SolutionEdge(_,y,x).

  conforms := !unusedBaseEdge &amp; !indexTooBig &amp; !doubleIndex &amp; !wrongSequence &amp; !doubleEdge &amp; !mirrorEdge.
}

/*
   Nikolaus graph:

     5
    / \
   3---4
   |\ /|
   | X |
   |/ \|
   1---2
*/

partial model nikolaus2 of EulerWay
{
    BaseEdge(1,2)
    BaseEdge(1,3)
    BaseEdge(1,4)
    BaseEdge(2,4)
    BaseEdge(2,3)
    BaseEdge(3,4)
    BaseEdge(3,5)
    BaseEdge(4,5)
    SolutionEdge(1,_,_)
    SolutionEdge(2,_,_)
    SolutionEdge(3,_,_)
    SolutionEdge(4,_,_)
    SolutionEdge(5,_,_)
    SolutionEdge(6,_,_)
    SolutionEdge(7,_,_)
    SolutionEdge(8,_,_)
}
</pre
				>

				<pre id="formula">
// Difficulty: 'Easy'
// Language definition for the Formula language
// More information at: http://rise4fun.com/formula
return {
  brackets: [
    ['{','}','delimiter.curly'],
    ['[',']','delimiter.square'],
    ['(',')','delimiter.parenthesis']
  ],

  keywords: [
    'domain', 'model', 'transform', 'system',
    'includes', 'extends', 'of', 'returns',
    'at', 'machine', 'is', 'no',
    'new', 'fun', 'inj', 'bij',
    'sur', 'any', 'ensures', 'requires',
    'some', 'atleast', 'atmost', 'partial',
    'initially', 'next', 'property', 'boot',
    'primitive'
  ],

  operators: [
    ':', '::', '..', '::=',
    ':-', '|', ';', ',',
    '=', '!=', '&lt;', '&lt;=',
    '&gt;', '&gt;=', '+', '-',
    '%', '/', '*'
  ],

  // operators
  symbols: /([\.]{2})|([=&gt;&lt;!:\|\+\-\*\/%,;]+)/,

  // escape sequences
  escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,

  tokenizer: {
    root : [
      { include: '@whitespace' },

      [ /[a-zA-Z_][\w_]*('*)/, {
          cases: {
              '@keywords': 'keyword',
              '@default': 'identifier'
          } } ],

      // delimiters
      [ /[\{\}\(\)\[\]]/, '@brackets' ],
      [ /`/, { token: 'delimiter.quote', next: '@quotation', bracket: "@open" } ],
      [ /\./, 'delimiter' ],

      // numbers
      [ /[\-\+]?\d+\/[\-\+]?\d*[1-9]/, 'string' ],
      [ /[\-\+]?\d+(\.\d+)?/, 'string' ],
      [ /@symbols/, { cases:{ '@operators': 'keyword',
                              '@default': 'symbols' } } ],

      // strings
      [/"([^"\\]|\\.)*$/, 'string.invalid' ],  // non-teminated string
      [/"/,  'string', '@string' ],
    ],

    unquote:  [
      { 'include' : '@root' },
      [ /\$/, 'predefined.identifier', '@pop' ]
    ],

    quotation:
    [
      [ /[^`\$]/, 'metatag' ],
      [ /`/, { token: 'delimiter.quote', bracket: '@close', next: '@pop' } ],
      [ /\$/, 'predefined.identifier', '@unquote' ]
    ],

    whitespace: [
      [/[ \t\r\n]+/, 'white'],
      [/\/\*/,       'comment', '@comment' ],
      [/\/\/.*$/,    'comment'],
    ],

    comment: [
      [/[^\/*]+/, 'comment' ],
      [/\/\*/, 'comment', '@push' ],    // nested comments
      [/\/\*/,    'comment.invalid' ],
      ["\\*/",    'comment', '@pop'  ],
      [/[\/*]/,   'comment' ]
    ],

    string: [
      [/[^"]+/,  'string'],
      // [/@escapes/, 'string.escape'],
      // [/\\./,      'string.escape.invalid'],
      [/"/,        'string', '@pop' ]
    ],
  }
};
</pre
				>
			</div>
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