Prism.languages.c = Prism.languages.extend('clike', {
	'comment': {
		pattern: /\/\/(?:[^\r\n\\]|\\(?:\r\n?|\n|(?![\r\n])))*|\/\*[\s\S]*?(?:\*\/|$)/,
		greedy: true
	},
	'string': {
		// https://en.cppreference.com/w/c/language/string_literal
		pattern: /"(?:\\(?:\r\n|[\s\S])|[^"\\\r\n])*"/,
		greedy: true
	},
	'class-name': {
		pattern: /(\b(?:enum|struct)\s+(?:__attribute__\s*\(\([\s\S]*?\)\)\s*)?)\w+|\b[a-z]\w*_t\b/,
		lookbehind: true
	},
	'keyword': /\b(?:_Alignas|_Alignof|_Atomic|_Bool|_Complex|_Generic|_Imaginary|_Noreturn|_Static_assert|_Thread_local|__attribute__|asm|auto|break|case|char|const|continue|default|do|double|else|enum|extern|float|for|goto|if|inline|int|long|register|return|short|signed|sizeof|static|struct|switch|typedef|typeof|union|unsigned|void|volatile|while)\b/,
	'function': /\b[a-z_]\w*(?=\s*\()/i,
	'number': /(?:\b0x(?:[\da-f]+(?:\.[\da-f]*)?|\.[\da-f]+)(?:p[+-]?\d+)?|(?:\b\d+(?:\.\d*)?|\B\.\d+)(?:e[+-]?\d+)?)[ful]{0,4}/i,
	'operator': />>=?|<<=?|->|([-+&|:])\1|[?:~]|[-+*/%&|^!=<>]=?/
});

Prism.languages.insertBefore('c', 'string', {
	'char': {
		// https://en.cppreference.com/w/c/language/character_constant
		pattern: /'(?:\\(?:\r\n|[\s\S])|[^'\\\r\n]){0,32}'/,
		greedy: true
	}
});

Prism.languages.insertBefore('c', 'string', {
	'macro': {
		// allow for multiline macro definitions
		// spaces after the # character compile fine with gcc
		pattern: /(^[\t ]*)#\s*[a-z](?:[^\r\n\\/]|\/(?!\*)|\/\*(?:[^*]|\*(?!\/))*\*\/|\\(?:\r\n|[\s\S]))*/im,
		lookbehind: true,
		greedy: true,
		alias: 'property',
		inside: {
			'string': [
				{
					// highlight the path of the include statement as a string
					pattern: /^(#\s*include\s*)<[^>]+>/,
					lookbehind: true
				},
				Prism.languages.c['string']
			],
			'char': Prism.languages.c['char'],
			'comment': Prism.languages.c['comment'],
			'macro-name': [
				{
					pattern: /(^#\s*define\s+)\w+\b(?!\()/i,
					lookbehind: true
				},
				{
					pattern: /(^#\s*define\s+)\w+\b(?=\()/i,
					lookbehind: true,
					alias: 'function'
				}
			],
			// highlight macro directives as keywords
			'directive': {
				pattern: /^(#\s*)[a-z]+/,
				lookbehind: true,
				alias: 'keyword'
			},
			'directive-hash': /^#/,
			'punctuation': /##|\\(?=[\r\n])/,
			'expression': {
				pattern: /\S[\s\S]*/,
				inside: Prism.languages.c
			}
		}
	}
});

Prism.languages.insertBefore('c', 'function', {
	// highlight predefined macros as constants
	'constant': /\b(?:EOF|NULL|SEEK_CUR|SEEK_END|SEEK_SET|__DATE__|__FILE__|__LINE__|__TIMESTAMP__|__TIME__|__func__|stderr|stdin|stdout)\b/
});

delete Prism.languages.c['boolean'];