Added basic support for LilyPond (#1967)

This adds very basic support for LilyPond. 
More advanced features weren't implemented because the author (me) has no idea about music.

components.json

@@ -507,6 +507,12 @@
 			"require": "css",
 			"owner": "Golmote"
 		},
+		"lilypond": {
+			"title": "LilyPond",
+			"require": "scheme",
+			"alias": "ly",
+			"owner": "RunDevelopment"
+		},
 		"liquid": {
 			"title": "Liquid",
 			"owner": "cinhtau"

components/prism-lilypond.js

@@ -0,0 +1,69 @@
+(function (Prism) {
+
+	var schemeExpression = /\((?:[^();"#\\]|\\[\s\S]|;.*|"(?:[^"\\]|\\.)*"|#(?:\{(?:(?!#\})[\s\S])*#\}|[^{])|<expr>)*\)/.source;
+	// allow for up to pow(2, recursivenessLog2) many levels of recursive brace expressions
+	// For some reason, this can't be 4
+	var recursivenessLog2 = 5;
+	for (var i = 0; i < recursivenessLog2; i++) {
+		schemeExpression = schemeExpression.replace(/<expr>/g, schemeExpression);
+	}
+	schemeExpression = schemeExpression.replace(/<expr>/g, /[^\s\S]/.source);
+
+
+	var lilypond = Prism.languages.lilypond = {
+		'comment': /%(?:(?!\{).*|\{[\s\S]*?%\})/,
+		'embedded-scheme': {
+			pattern: RegExp(/(^|[=\s])#(?:"(?:[^"\\]|\\.)*"|[^\s()"]*(?:[^\s()]|<expr>))/.source.replace(/<expr>/g, schemeExpression), 'm'),
+			lookbehind: true,
+			greedy: true,
+			inside: {
+				'scheme': {
+					pattern: /^(#)[\s\S]+$/,
+					lookbehind: true,
+					alias: 'language-scheme',
+					inside: {
+						'embedded-lilypond': {
+							pattern: /#\{[\s\S]*?#\}/,
+							greedy: true,
+							inside: {
+								'punctuation': /^#\{|#\}$/,
+								'lilypond': {
+									pattern: /[\s\S]+/,
+									alias: 'language-lilypond',
+									inside: null // see below
+								}
+							}
+						},
+						rest: Prism.languages.scheme
+					}
+				},
+				'punctuation': /#/
+			}
+		},
+		'string': {
+			pattern: /"(?:[^"\\]|\\.)*"/,
+			greedy: true
+		},
+		'class-name': {
+			pattern: /(\\new\s+)[\w-]+/,
+			lookbehind: true
+		},
+		'keyword': {
+			pattern: /\\[a-z][-\w]*/i,
+			inside: {
+				'punctuation': /^\\/
+			}
+		},
+		'operator': /[=|]|<<|>>/,
+		'punctuation': {
+			pattern: /(^|[a-z\d])(?:'+|,+|[_^]?-[_^]?(?:[-+^!>._]|(?=\d))|[_^]\.?|[.!])|[{}()[\]<>^~]|\\[()[\]<>\\!]|--|__/,
+			lookbehind: true
+		},
+		'number': /\b\d+(?:\/\d+)?\b/
+	};
+
+	lilypond['embedded-scheme'].inside['scheme'].inside['embedded-lilypond'].inside['lilypond'].inside = lilypond;
+
+	Prism.languages.ly = lilypond;
+
+}(Prism));

plugins/autoloader/prism-autoloader.js

@@ -55,6 +55,7 @@
 		"json5": "json",
 		"kotlin": "clike",
 		"less": "css",
+		"lilypond": "scheme",
 		"markdown": "markup",
 		"markup-templating": "markup",
 		"n4js": "javascript",
@@ -139,6 +140,7 @@
 		"hs": "haskell",
 		"tex": "latex",
 		"context": "latex",
+		"ly": "lilypond",
 		"emacs": "lisp",
 		"elisp": "lisp",
 		"emacs-lisp": "lisp",

plugins/show-language/prism-show-language.js

@@ -77,6 +77,8 @@
 		"latex": "LaTeX",
 		"tex": "TeX",
 		"context": "ConTeXt",
+		"lilypond": "LilyPond",
+		"ly": "LilyPond",
 		"emacs": "Lisp",
 		"elisp": "Lisp",
 		"emacs-lisp": "Lisp",

tests/languages/lilypond/comment_feature.test

@@ -0,0 +1,16 @@
+% single line
+
+%{
+multiple lines
+%}
+
+----------------------------------------------------
+
+[
+	["comment", "% single line"],
+	["comment", "%{\nmultiple lines\n%}"]
+]
+
+----------------------------------------------------
+
+Checks for comments.

tests/languages/lilypond/embedded-scheme_feature.test

@@ -0,0 +1,86 @@
+#(define foo)
+
+#(define-music-function (parser location notes) (ly:music?) #{
+	% Yes! You can embed LilyPond in Scheme.
+	\override Score.Stem.beamlet-max-length-proportion = #'(0.5 . 0.5)
+#})
+
+##t
+
+#"s t r i n g"
+
+----------------------------------------------------
+
+[
+	["embedded-scheme", [
+		["punctuation", "#"],
+		["scheme", [
+			["punctuation", "("],
+			["keyword", "define"],
+			" foo",
+			["punctuation", ")"]
+		]]
+	]],
+
+	["embedded-scheme", [
+		["punctuation", "#"],
+		["scheme", [
+			["punctuation", "("],
+			["function", "define-music-function"],
+			["punctuation", "("],
+			["function", "parser"],
+			" location notes",
+			["punctuation", ")"],
+			["punctuation", "("],
+			["function", "ly:music?"],
+			["punctuation", ")"],
+			["embedded-lilypond", [
+				["punctuation", "#{"],
+				["lilypond", [
+					["comment", "% Yes! You can embed LilyPond in Scheme."],
+					["keyword", [
+						["punctuation", "\\"],
+						"override"
+					]],
+					" Score",
+					["punctuation", "."],
+					"Stem",
+					["punctuation", "."],
+					"beamlet-max-length-proportion ",
+					["operator", "="],
+					["embedded-scheme", [
+						["punctuation", "#"],
+						["scheme", [
+							["punctuation", "'"],
+							["punctuation", "("],
+							["number", "0.5"],
+							" . ",
+							["number", "0.5"],
+							["punctuation", ")"]
+						]]
+					]]
+				]],
+				["punctuation", "#}"]
+			]],
+			["punctuation", ")"]
+		]]
+	]],
+
+	["embedded-scheme", [
+		["punctuation", "#"],
+		["scheme", [
+			["boolean", "#t"]
+		]]
+	]],
+
+	["embedded-scheme", [
+		["punctuation", "#"],
+		["scheme", [
+			["string", "\"s t r i n g\""]
+		]]
+	]]
+]
+
+----------------------------------------------------
+
+Checks for Scheme code embedded in LilyPond.

tests/languages/lilypond/keyword_feature.test

@@ -0,0 +1,35 @@
+\new \set
+\center-column
+5\mm
+h\fermata
+
+----------------------------------------------------
+
+[
+	["keyword", [
+		["punctuation", "\\"],
+		"new"
+	]],
+	["keyword", [
+		["punctuation", "\\"],
+		"set"
+	]],
+	["keyword", [
+		["punctuation", "\\"],
+		"center-column"
+	]],
+	["number", "5"],
+	["keyword", [
+		["punctuation", "\\"],
+		"mm"
+	]],
+	"\nh",
+	["keyword", [
+		["punctuation", "\\"],
+		"fermata"
+	]]
+]
+
+----------------------------------------------------
+
+Checks for keywords.

tests/languages/lilypond/number_feature.test

@@ -0,0 +1,13 @@
+123
+6/8
+
+----------------------------------------------------
+
+[
+	["number", "123"],
+	["number", "6/8"]
+]
+
+----------------------------------------------------
+
+Checks for numbers.