PHP RFC: Your Title Here

• Version: 1.0
• Date: 2015-03-10
• Author: Wei Dai, demon@php.net
• Status: Draft
• First Published at: https://wiki.php.net/rfc/preg_replace_callback_array

The preg_replace_callback_array function is an extension to preg_replace_callback. With the function, each pattern can easily have a specific callback.

This is the best way to implement when there are multiple patterns.

Below is the previous code, which is from Zend/zend_vm_gen.php.

$code = preg_replace_callback(
    array(
        "/EXECUTE_DATA/m",
	"/ZEND_VM_DISPATCH_TO_HANDLER\(\s*([A-Z_]*)\s*\)/m",
	"/ZEND_VM_DISPATCH_TO_HELPER\(\s*([A-Za-z_]*)\s*\)/m",
	"/ZEND_VM_DISPATCH_TO_HELPER_EX\(\s*([A-Za-z_]*)\s*,\s*[A-Za-z_]*\s*,\s*(.*)\s*\);/m",
    ),
    function($matches) use ($spec, $prefix, $op1, $op2) {
	if (strncasecmp($matches[0], "EXECUTE_DATA", strlen("EXECUTE_DATA")) == 0) {
	    return "execute_data";
        } else if (strncasecmp($matches[0], "ZEND_VM_DISPATCH_TO_HANDLER", strlen("ZEND_VM_DISPATCH_TO_HANDLER")) == 0) {
	    return "return " . $matches[1] . ($spec?"_SPEC":"") . $prefix[$op1] . $prefix[$op2] . "_HANDLER(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU)";
        } else if (strncasecmp($matches[0], "ZEND_VM_DISPATCH_TO_HELPER_EX", strlen("ZEND_VM_DISPATCH_TO_HELPER_EX")) == 0) {
	    return "return " . helper_name($matches[1], $spec, $op1, $op2) . "(" . $matches[2]. ", ZEND_OPCODE_HANDLER_ARGS_PASSTHRU);";
        } else {
	    return "return " . helper_name($matches[1], $spec, $op1, $op2) . "(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU)";
        }
    }, $code);

With preg_replace_callback_array, the code is more readable, and full of logic. There is less crazy branch determination.

$code = preg_replace_callback_array(
	array(
		"/EXECUTE_DATA/m" => function($matches) {
                        return "execute_data";
                 },
		"/ZEND_VM_DISPATCH_TO_HANDLER\(\s*([A-Z_]*)\s*\)/m" => function($matches) use ($spec, $prefix, $op1, $op2) {
		       return "return " . $matches[1] . ($spec?"_SPEC":"") . $prefix[$op1] . $prefix[$op2] . "_HANDLER(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU)";
		},
		"/ZEND_VM_DISPATCH_TO_HELPER\(\s*([A-Za-z_]*)\s*\)/m" => function($matches) use ($spec, $prefix, $op1, $op2) {
			return "return " . helper_name($matches[1], $spec, $op1, $op2) . "(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU)";
		},
		"/ZEND_VM_DISPATCH_TO_HELPER_EX\(\s*([A-Za-z_]*)\s*,\s*[A-Za-z_]*\s*,\s*(.*)\s*\);/m" => function($matches) use ($spec, $prefix, $op1, $op2) {
			return "return " . helper_name($matches[1], $spec, $op1, $op2) . "(" . $matches[2]. ", ZEND_OPCODE_HANDLER_ARGS_PASSTHRU);";
		},
	), $code);

The first parameter is an array in this function. In this parameter, Key is parameter, and value is callback. Subject will iterate and match each key. If it is matched, the callback will be called. In the meanwhile, the result will be the new subject and passed to the next match.

= PHP 7.0.0

preg_filter(), preg_replace(), preg_replace_callback() will stay the same.

Include these so readers know where you are heading and can discuss the proposed voting options.

State whether this project requires a 2/3 or 50%+1 majority (see voting)

Write it later.