GitFOSS

Prism.languages.elm = {
	'comment': /--.*|\{-[\s\S]*?-\}/,
	'char': {
		pattern: /'(?:[^\\'\r\n]|\\(?:[abfnrtv\\']|\d+|x[0-9a-fA-F]+|u\{[0-9a-fA-F]+\}))'/,
		greedy: true
	},
	'string': [
		{
			// Multiline strings are wrapped in triple ". Quotes may appear unescaped.
			pattern: /"""[\s\S]*?"""/,
			greedy: true
		},
		{
			pattern: /"(?:[^\\"\r\n]|\\.)*"/,
			greedy: true
		}
	],
	'import-statement': {
		// The imported or hidden names are not included in this import
		// statement. This is because we want to highlight those exactly like
		// we do for the names in the program.
		pattern: /(^[\t ]*)import\s+[A-Z]\w*(?:\.[A-Z]\w*)*(?:\s+as\s+(?:[A-Z]\w*)(?:\.[A-Z]\w*)*)?(?:\s+exposing\s+)?/m,
		lookbehind: true,
		inside: {
			'keyword': /\b(?:as|exposing|import)\b/
		}
	},
	'keyword': /\b(?:alias|as|case|else|exposing|if|in|infixl|infixr|let|module|of|then|type)\b/,
	// These are builtin variables only. Constructors are highlighted later as a constant.
	'builtin': /\b(?:abs|acos|always|asin|atan|atan2|ceiling|clamp|compare|cos|curry|degrees|e|flip|floor|fromPolar|identity|isInfinite|isNaN|logBase|max|min|negate|never|not|pi|radians|rem|round|sin|sqrt|tan|toFloat|toPolar|toString|truncate|turns|uncurry|xor)\b/,
	// decimal integers and floating point numbers | hexadecimal integers
	'number': /\b(?:\d+(?:\.\d+)?(?:e[+-]?\d+)?|0x[0-9a-f]+)\b/i,
	// Most of this is needed because of the meaning of a single '.'.
	// If it stands alone freely, it is the function composition.
	// It may also be a separator between a module name and an identifier => no
	// operator. If it comes together with other special characters it is an
	// operator too.
	// Valid operator characters in 0.18: +-/*=.$<>:&|^?%#@~!
	// Ref: https://groups.google.com/forum/#!msg/elm-dev/0AHSnDdkSkQ/E0SVU70JEQAJ
	'operator': /\s\.\s|[+\-/*=.$<>:&|^?%#@~!]{2,}|[+\-/*=$<>:&|^?%#@~!]/,
	// In Elm, nearly everything is a variable, do not highlight these.
	'hvariable': /\b(?:[A-Z]\w*\.)*[a-z]\w*\b/,
	'constant': /\b(?:[A-Z]\w*\.)*[A-Z]\w*\b/,
	'punctuation': /[{}[\]|(),.:]/
};