(function(Prism) {
	Prism.languages.crystal = Prism.languages.extend('ruby', {
		keyword: [
			/\b(?:abstract|alias|as|asm|begin|break|case|class|def|do|else|elsif|end|ensure|enum|extend|for|fun|if|include|instance_sizeof|lib|macro|module|next|of|out|pointerof|private|protected|rescue|return|require|select|self|sizeof|struct|super|then|type|typeof|uninitialized|union|unless|until|when|while|with|yield|__DIR__|__END_LINE__|__FILE__|__LINE__)\b/,
			{
				pattern: /(\.\s*)(?:is_a|responds_to)\?/,
				lookbehind: true
			}
		],

		number: /\b(?:0b[01_]*[01]|0o[0-7_]*[0-7]|0x[0-9a-fA-F_]*[0-9a-fA-F]|(?:\d(?:[0-9_]*\d)?)(?:\.[0-9_]*\d)?(?:[eE][+-]?[0-9_]*\d)?)(?:_(?:[uif](?:8|16|32|64))?)?\b/
	});

	var rest = Prism.util.clone(Prism.languages.crystal);

	Prism.languages.insertBefore('crystal', 'string', {
		attribute: {
			pattern: /@\[.+?\]/,
			alias: 'attr-name',
			inside: {
				delimiter: {
					pattern: /^@\[|\]$/,
					alias: 'tag'
				},
				rest: rest
			}
		},

		expansion: [
		{
			pattern: /\{\{.+?\}\}/,
			inside: {
				delimiter: {
					pattern: /^\{\{|\}\}$/,
					alias: 'tag'
				},
				rest: rest
			}
		},
		{
			pattern: /\{%.+?%\}/,
			inside: {
				delimiter: {
					pattern: /^\{%|%\}$/,
					alias: 'tag'
				},
				rest: rest
			}
		}
		]
	});

}(Prism));