(function (Prism) {

	var specialEscape = {
		pattern: /\\[\\(){}[\]^$+*?|.]/,
		alias: 'escape'
	};
	var escape = /\\(?:x[\da-fA-F]{2}|u[\da-fA-F]{4}|u\{[\da-fA-F]+\}|c[a-zA-Z]|0[0-7]{0,2}|[123][0-7]{2}|.)/;
	var charClass = {
		pattern: /\.|\\[wsd]|\\p{[^{}]+}/i,
		alias: 'class-name'
	};
	var charClassWithoutDot = {
		pattern: /\\[wsd]|\\p{[^{}]+}/i,
		alias: 'class-name'
	};

	var rangeChar = '(?:[^\\\\-]|' + escape.source + ')';
	var range = RegExp(rangeChar + '-' + rangeChar);

	// the name of a capturing group
	var groupName = {
		pattern: /(<|')[^<>']+(?=[>']$)/,
		lookbehind: true,
		alias: 'variable'
	};

	Prism.languages.regex = {
		'charset': {
			pattern: /((?:^|[^\\])(?:\\\\)*)\[(?:[^\\\]]|\\[\s\S])*\]/,
			lookbehind: true,
			inside: {
				'charset-negation': {
					pattern: /(^\[)\^/,
					lookbehind: true,
					alias: 'operator'
				},
				'charset-punctuation': {
					pattern: /^\[|\]$/,
					alias: 'punctuation'
				},
				'range': {
					pattern: range,
					inside: {
						'escape': escape,
						'range-punctuation': {
							pattern: /-/,
							alias: 'operator'
						}
					}
				},
				'special-escape': specialEscape,
				'charclass': charClassWithoutDot,
				'escape': escape
			}
		},
		'special-escape': specialEscape,
		'charclass': charClass,
		'backreference': [
			{
				// a backreference which is not an octal escape
				pattern: /\\(?![123][0-7]{2})[1-9]/,
				alias: 'keyword'
			},
			{
				pattern: /\\k<[^<>']+>/,
				alias: 'keyword',
				inside: {
					'group-name': groupName
				}
			}
		],
		'anchor': {
			pattern: /[$^]|\\[ABbGZz]/,
			alias: 'function'
		},
		'escape': escape,
		'group': [
			{
				// https://docs.oracle.com/javase/10/docs/api/java/util/regex/Pattern.html
				// https://docs.microsoft.com/en-us/dotnet/standard/base-types/regular-expression-language-quick-reference?view=netframework-4.7.2#grouping-constructs

				// (), (?<name>), (?'name'), (?>), (?:), (?=), (?!), (?<=), (?<!), (?is-m), (?i-m:)
				pattern: /\((?:\?(?:<[^<>']+>|'[^<>']+'|[>:]|<?[=!]|[idmnsuxU]+(?:-[idmnsuxU]+)?:?))?/,
				alias: 'punctuation',
				inside: {
					'group-name': groupName
				}
			},
			{
				pattern: /\)/,
				alias: 'punctuation'
			}
		],
		'quantifier': {
			pattern: /(?:[+*?]|\{\d+(?:,\d*)?\})[?+]?/,
			alias: 'number'
		},
		'alternation': {
			pattern: /\|/,
			alias: 'keyword'
		}
	};

}(Prism))
