Added support for ASP.NET Razor

components.json

@@ -1086,6 +1086,18 @@
 			"alias": "rkt",
 			"owner": "RunDevelopment"
 		},
+		"cshtml": {
+			"title": "Razor C#",
+			"alias": "razor",
+			"require": ["markup", "csharp"],
+			"optional":[
+				"css",
+				"css-extras",
+				"javascript",
+				"js-extras"
+			],
+			"owner": "RunDevelopment"
+		},
 		"jsx": {
 			"title": "React JSX",
 			"require": ["markup", "javascript"],

components/prism-cshtml.js

@@ -0,0 +1,183 @@
+// Docs:
+// https://docs.microsoft.com/en-us/aspnet/core/razor-pages/?view=aspnetcore-5.0&tabs=visual-studio
+// https://docs.microsoft.com/en-us/aspnet/core/mvc/views/razor?view=aspnetcore-5.0
+
+(function (Prism) {
+
+	var commentLike = /\/(?![/*])|\/\/.*[\r\n]|\/\*[^*]*(?:\*(?!\/)[^*]*)*\*\//.source;
+	var stringLike =
+		/@(?!")|"(?:[^\r\n\\"]|\\.)*"|@"(?:[^\\"]|""|\\[\s\S])*"(?!")/.source +
+		'|' +
+		/'(?:(?:[^\r\n'\\]|\\.|\\[Uux][\da-fA-F]{1,8})'|(?=[^\\](?!')))/.source;
+
+	/**
+	 * Creates a nested pattern where all occurrences of the string `<<self>>` are replaced with the pattern itself.
+	 *
+	 * @param {string} pattern
+	 * @param {number} depthLog2
+	 * @returns {string}
+	 */
+	function nested(pattern, depthLog2) {
+		for (var i = 0; i < depthLog2; i++) {
+			pattern = pattern.replace(/<self>/g, function () { return '(?:' + pattern + ')'; });
+		}
+		return pattern
+			.replace(/<self>/g, '[^\\s\\S]')
+			.replace(/<str>/g, '(?:' + stringLike + ')')
+			.replace(/<comment>/g, '(?:' + commentLike + ')');
+	}
+
+	var round = nested(/\((?:[^()'"@/]|<str>|<comment>|<self>)*\)/.source, 2);
+	var square = nested(/\[(?:[^\[\]'"@/]|<str>|<comment>|<self>)*\]/.source, 2);
+	var curly = nested(/\{(?:[^{}'"@/]|<str>|<comment>|<self>)*\}/.source, 2);
+	var angle = nested(/<(?:[^<>'"@/]|<str>|<comment>|<self>)*>/.source, 2);
+
+	// Note about the above bracket patterns:
+	// They all ignore HTML expressions that might be in the C# code. This is a problem because HTML (like strings and
+	// comments) is parsed differently. This is a huge problem because HTML might contain brackets and quotes which
+	// messes up the bracket and string counting implemented by the above patterns.
+	//
+	// This problem is not fixable because 1) HTML expression are highly context sensitive and very difficult to detect
+	// and 2) they require one capturing group at every nested level. See the `tagRegion` pattern to admire the
+	// complexity of an HTML expression.
+	//
+	// To somewhat alleviate the problem a bit, the patterns for characters (e.g. 'a') is very permissive, it also
+	// allows invalid characters to support HTML expressions like this: <p>That's it!</p>.
+
+	var tagAttrs = /(?:\s(?:\s*[^\s>\/=]+(?:\s*=\s*(?:"[^"]*"|'[^']*'|[^\s'">=]+(?=[\s>]))|(?=[\s/>])))+)?/.source;
+	var tagContent = /(?!\d)[^\s>\/=$<%]+/.source + tagAttrs + /\s*\/?>/.source;
+	var tagRegion =
+		/\B@?/.source +
+		'(?:' +
+		/<([a-zA-Z][\w:]*)/.source + tagAttrs + /\s*>/.source +
+		'(?:' +
+		(
+			/[^<]/.source +
+			'|' +
+			// all tags that are not the start tag
+			// eslint-disable-next-line regexp/strict
+			/<\/?(?!\1\b)/.source + tagContent +
+			'|' +
+			// nested start tag
+			nested(
+				// eslint-disable-next-line regexp/strict
+				/<\1/.source + tagAttrs + /\s*>/.source +
+				'(?:' +
+				(
+					/[^<]/.source +
+					'|' +
+					// all tags that are not the start tag
+					// eslint-disable-next-line regexp/strict
+					/<\/?(?!\1\b)/.source + tagContent +
+					'|' +
+					'<self>'
+				) +
+				')*' +
+				// eslint-disable-next-line regexp/strict
+				/<\/\1\s*>/.source,
+				2
+			)
+		) +
+		')*' +
+		// eslint-disable-next-line regexp/strict
+		/<\/\1\s*>/.source +
+		'|' +
+		/</.source + tagContent +
+		')';
+
+	// Now for the actual language definition(s):
+	//
+	// Razor as a language has 2 parts:
+	//  1) CSHTML: A markup-like language that has been extended with inline C# code expressions and blocks.
+	//  2) C#+HTML: A variant of C# that can contain CSHTML tags as expressions.
+	//
+	// In the below code, both CSHTML and C#+HTML will be create as separate language definitions that reference each
+	// other. However, only CSHTML will be exported via `Prism.languages`.
+
+	Prism.languages.cshtml = Prism.languages.extend('markup', {});
+
+	var csharpWithHtml = Prism.languages.insertBefore('csharp', 'string', {
+		'html': {
+			pattern: RegExp(tagRegion),
+			greedy: true,
+			inside: Prism.languages.cshtml
+		},
+	}, { csharp: Prism.languages.extend('csharp', {}) });
+
+	var cs = {
+		pattern: /\S[\s\S]*/,
+		alias: 'language-csharp',
+		inside: csharpWithHtml
+	};
+
+	Prism.languages.insertBefore('cshtml', 'prolog', {
+		'razor-comment': {
+			pattern: /@\*[\s\S]*?\*@/,
+			greedy: true,
+			alias: 'comment'
+		},
+
+		'block': {
+			pattern: RegExp(
+				/(^|[^@])@/.source +
+				'(?:' +
+				[
+					// @{ ... }
+					curly,
+					// @code{ ... }
+					/(?:code|functions)\s*/.source + curly,
+					// @for (...) { ... }
+					/(?:for|foreach|lock|switch|using|while)\s*/.source + round + /\s*/.source + curly,
+					// @do { ... } while (...);
+					/do\s*/.source + curly + /\s*while\s*/.source + round + /(?:\s*;)?/.source,
+					// @try { ... } catch (...) { ... } finally { ... }
+					/try\s*/.source + curly + /\s*catch\s*/.source + round + /\s*/.source + curly + /\s*finally\s*/.source + curly,
+					// @if (...) {...} else if (...) {...} else {...}
+					/if\s*/.source + round + /\s*/.source + curly + '(?:' + /\s*else/.source + '(?:' + /\s+if\s*/.source + round + ')?' + /\s*/.source + curly + ')*',
+				].join('|') +
+				')'
+			),
+			lookbehind: true,
+			greedy: true,
+			inside: {
+				'keyword': /^@\w*/,
+				'csharp': cs
+			}
+		},
+
+		'directive': {
+			pattern: /^([ \t]*)@(?:addTagHelper|attribute|implements|inherits|inject|layout|model|namespace|page|preservewhitespace|removeTagHelper|section|tagHelperPrefix|using)(?=\s).*/m,
+			lookbehind: true,
+			greedy: true,
+			inside: {
+				'keyword': /^@\w+/,
+				'csharp': cs
+			}
+		},
+
+		'value': {
+			pattern: RegExp(
+				/(^|[^@])@/.source +
+				/(?:await\b\s*)?/.source +
+				'(?:' + /\w+\b/.source + '|' + round + ')' +
+				'(?:' + /[?!]?\.\w+\b/.source + '|' + round + '|' + square + '|' + angle + round + ')*'
+			),
+			lookbehind: true,
+			greedy: true,
+			alias: 'variable',
+			inside: {
+				'keyword': /^@/,
+				'csharp': cs
+			}
+		},
+
+		'delegate-operator': {
+			pattern: /(^|[^@])@(?=<)/,
+			lookbehind: true,
+			alias: 'operator'
+		}
+	});
+
+	Prism.languages.razor = Prism.languages.cshtml;
+
+}(Prism));

examples/prism-cshtml.html

@@ -0,0 +1,36 @@
+<h2>Full example</h2>
+<pre><code>@* Source: https://docs.microsoft.com/en-us/aspnet/core/razor-pages/?view=aspnetcore-5.0&amp;tabs=visual-studio#the-home-page *@
+
+@page
+@model RazorPagesContacts.Pages.Customers.IndexModel
+@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
+
+&lt;h1>Contacts home page&lt;/h1>
+&lt;form method="post">
+	&lt;table class="table">
+		&lt;thead>
+			&lt;tr>
+				&lt;th>ID&lt;/th>
+				&lt;th>Name&lt;/th>
+				&lt;th>&lt;/th>
+			&lt;/tr>
+		&lt;/thead>
+		&lt;tbody>
+			@foreach (var contact in Model.Customer)
+			{
+				&lt;tr>
+					&lt;td> @contact.Id  &lt;/td>
+					&lt;td>@contact.Name&lt;/td>
+					&lt;td>
+						&lt;a asp-page="./Edit" asp-route-id="@contact.Id">Edit&lt;/a> |
+						&lt;button type="submit" asp-page-handler="delete"
+								asp-route-id="@contact.Id">delete
+						&lt;/button>
+					&lt;/td>
+				&lt;/tr>
+			}
+		&lt;/tbody>
+	&lt;/table>
+	&lt;a asp-page="Create">Create New&lt;/a>
+&lt;/form>
+</code></pre>

plugins/autoloader/prism-autoloader.js

@@ -115,6 +115,10 @@
 		"qml": "javascript",
 		"qore": "clike",
 		"racket": "scheme",
+		"cshtml": [
+			"markup",
+			"csharp"
+		],
 		"jsx": [
 			"markup",
 			"javascript"
@@ -224,6 +228,7 @@
 		"py": "python",
 		"qs": "qsharp",
 		"rkt": "racket",
+		"razor": "cshtml",
 		"rpy": "renpy",
 		"robot": "robotframework",
 		"rb": "ruby",