confusion.php

<?php
$source = './a';
$desc = './b';

$words = array(
	'and' => 1,
	'__LINE__' => 1,
	'class' => 1,
	'die' => 1,
	'empty' => 1,
	'endswitch' => 1,
	'for' => 1,
	'include' => 1,
	'print' => 1,
	'switch' => 1,
	'__FUNCTION__' => 1,
	'interface' => 1,
	'protected' => 1,
	'throw' => 1,
	'or' => 1,
	'array' => 1,
	'const' => 1,
	'do' => 1,
	'enddeclare' => 1,
	'endwhile' => 1,
	'foreach' => 1,
	'include_once' => 1,
	'require' => 1,
	'unset' => 1,
	'__CLASS__' => 1,
	'implements' => 1,
	'abstract' => 1,
	'xor' => 1,
	'as' => 1,
	'continue' => 1,
	'echo' => 1,
	'endfor' => 1,
	'eval' => 1,
	'function' => 1,
	'isset' => 1,
	'require_once' => 1,
	'use' => 1,
	'__METHOD__' => 1,
	'extends' => 1,
	'clone' => 1,
	'this' => 1,
	'__FILE__' => 1,
	'break' => 1,
	'declare' => 1,
	'else' => 1,
	'endforeach' => 1,
	'exit' => 1,
	'global' => 1,
	'list' => 1,
	'return' => 1,
	'var' => 1,
	'final' => 1,
	'public' => 1,
	'try' => 1,
	'exception' => 1,
	'case' => 1,
	'default' => 1,
	'elseif' => 1,
	'endif' => 1,
	'extends' => 1,
	'if' => 1,
	'new' => 1,
	'static' => 1,
	'while' => 1,
	'php_user_filter' => 1,
	'private' => 1,
	'catch' => 1,
	'self' => 1,
	'parent' => 1,
	'_GET' => 1,
	'_POST' => 1,
	'_REQUEST' => 1,
);
function walk($pattern){
	$files = glob($pattern);
	foreach(array_reverse(glob(dirname($pattern).'/*', GLOB_ONLYDIR|GLOB_NOSORT)) as $dir){
		$files = array_merge(walk($dir.'/'.basename($pattern)), $files);
	}
	return $files;
}

$files = walk($source . '/*.php');

$function_hash = array();
$variable_hash = array();
$output = '';
foreach ($files as $filename) {
	$tokens = token_get_all(file_get_contents($filename));
	foreach ($tokens as $token) {
		if (is_array($token)) {
			if (defined($token[1]) || isset($words[$token[1]]) || strtoupper($token[1]) == $token[1]) {
				$output .= $token[1];
			} elseif ($token[0] == T_STRING) {
				if (!function_exists($token[1])) {
					if (!isset($function_hash[$token[1]])) {
						$function_hash[$token[1]] = count($function_hash);
					}
					$output .= "_{$function_hash[$token[1]]}";
				} else {
					$output .= $token[1];
				}
			} elseif ($token[0] == T_VARIABLE) {

				$word = ltrim($token[1], '$');
				if(!isset($words[$word])) {
					if (!isset($variable_hash[$word])) {
						$variable_hash[$word] = count($variable_hash);
					}
					$output .= "\$_{$variable_hash[$word]}";

				} else {
					$output .= $token[1];
				}

			} else {
				$output .= $token[1];
			}
		} else {
			$output .= $token;
		}
	}
	$newname = $desc . substr($filename, strlen($source));
	if(!is_dir($dir = dirname($newname))) {
		mkdir($dir, 0755, true);
	}
	file_put_contents($newname, $output);
}