(function (Prism) {

	// https://yaml.org/spec/1.2/spec.html#c-ns-anchor-property
	// https://yaml.org/spec/1.2/spec.html#c-ns-alias-node
	var anchorOrAlias = /[*&][^\s[\]{},]+/;
	// https://yaml.org/spec/1.2/spec.html#c-ns-tag-property
	var tag = /!(?:<[\w\-%#;/?:@&=+$,.!~*'()[\]]+>|(?:[a-zA-Z\d-]*!)?[\w\-%#;/?:@&=+$.~*'()]+)?/;
	// https://yaml.org/spec/1.2/spec.html#c-ns-properties(n,c)
	var properties = '(?:' + tag.source + '(?:[ \t]+' + anchorOrAlias.source + ')?|'
		+ anchorOrAlias.source + '(?:[ \t]+' + tag.source + ')?)';

	/**
	 *
	 * @param {string} value
	 * @param {string} [flags]
	 * @returns {RegExp}
	 */
	function createValuePattern(value, flags) {
		flags = (flags || '').replace(/m/g, '') + 'm'; // add m flag
		var pattern = /([:\-,[{]\s*(?:\s<<prop>>[ \t]+)?)(?:<<value>>)(?=[ \t]*(?:$|,|]|}|\s*#))/.source
			.replace(/<<prop>>/g, function () { return properties; }).replace(/<<value>>/g, function () { return value; });
		return RegExp(pattern, flags)
	}

	Prism.languages.yaml = {
		'scalar': {
			pattern: RegExp(/([\-:]\s*(?:\s<<prop>>[ \t]+)?[|>])[ \t]*(?:((?:\r?\n|\r)[ \t]+)[^\r\n]+(?:\2[^\r\n]+)*)/.source
				.replace(/<<prop>>/g, function () { return properties; })),
			lookbehind: true,
			alias: 'string'
		},
		'comment': /#.*/,
		'key': {
			pattern: RegExp(/((?:^|[:\-,[{\r\n?])[ \t]*(?:<<prop>>[ \t]+)?)[^\r\n{[\]},#\s]+?(?=\s*:\s)/.source
				.replace(/<<prop>>/g, function () { return properties; })),
			lookbehind: true,
			alias: 'atrule'
		},
		'directive': {
			pattern: /(^[ \t]*)%.+/m,
			lookbehind: true,
			alias: 'important'
		},
		'datetime': {
			pattern: createValuePattern(/\d{4}-\d\d?-\d\d?(?:[tT]|[ \t]+)\d\d?:\d{2}:\d{2}(?:\.\d*)?[ \t]*(?:Z|[-+]\d\d?(?::\d{2})?)?|\d{4}-\d{2}-\d{2}|\d\d?:\d{2}(?::\d{2}(?:\.\d*)?)?/.source),
			lookbehind: true,
			alias: 'number'
		},
		'boolean': {
			pattern: createValuePattern(/true|false/.source, 'i'),
			lookbehind: true,
			alias: 'important'
		},
		'null': {
			pattern: createValuePattern(/null|~/.source, 'i'),
			lookbehind: true,
			alias: 'important'
		},
		'string': {
			// \2 because of the lookbehind group
			pattern: createValuePattern(/("|')(?:(?!\2)[^\\\r\n]|\\.)*\2/.source),
			lookbehind: true,
			greedy: true
		},
		'number': {
			pattern: createValuePattern(/[+-]?(?:0x[\da-f]+|0o[0-7]+|(?:\d+\.?\d*|\.?\d+)(?:e[+-]?\d+)?|\.inf|\.nan)/.source, 'i'),
			lookbehind: true
		},
		'tag': tag,
		'important': anchorOrAlias,
		'punctuation': /---|[:[\]{}\-,|>?]|\.\.\./
	};

	Prism.languages.yml = Prism.languages.yaml;

}(Prism));