php实现简单的语法高亮函数

一个php实现的简单语法高亮显示的函数，注意：这个函数设计的比较简单，可能对某些语法不能高亮显示，你可以自己扩充该函数的功能.

function syntax_highlight($code){
   
    // this matches --> "foobar" <--
    $code = preg_replace(
        '/"(.*?)"/U',
        '"$1"', $code
    );
   
    // hightlight functions and other structures like --> function foobar() <---
    $code = preg_replace(
        '/(\s)\b(.*?)((\b|\s)\()/U',
        '$1$2$3',
        $code
    );
   
    // Match comments (like /* */):
    $code = preg_replace(
        '/(\/\/)(.+)\s/',
        '$0',
        $code
    );
   
    $code = preg_replace(
        '/(\/\*.*?\*\/)/s',
        '$0',
        $code
    );
   
    // hightlight braces:
    $code = preg_replace('/(\(|\[|\{|\}|\]|\)|\->)/', '$1', $code);
   
    // hightlight variables $foobar
    $code = preg_replace(
        '/(\$[a-zA-Z0-9_]+)/', '$1', $code
    );
   
    /* The \b in the pattern indicates a word boundary, so only the distinct
    ** word "web" is matched, and not a word partial like "webbing" or "cobweb"
    */
   
    // special words and functions
    $code = preg_replace(
        '/\b(print|echo|new|function)\b/',
        '$1', $code
    );
   
    return $code;
}
   
   
/*example-start*/
   
/*
** Create some example PHP code:
*/
   
$example_php_code = '
// some code comment:
$example = "foobar";
   
print $_SERVER["REMOTE_ADDR"];
   
$array = array(1, 2, 3, 4, 5);
   
function example_function($str) {
    // reverse string
    echo strrev($obj);
}
   
print example_function("foo");
   
/*
** A multiple line comment
*/
   
print "Something: " . $example;';
   
   
// output the formatted code:
print '
';
print syntax_highlight($example_php_code);
print '
';
   
/*example-end*/