Convert php code to string, opposite to eval()

Question

How can I convert callable (anonymous function) into a string for eval?

I'm trying to write unit tests in phpunit that use runkit to override methods. And in particular, runkit_method_redefine() requires a string parameter that will be eval()-called later.

I want to have syntax highlighting of my test code, so I don't want to write code inside of a string, so I want to do something like

deEval(function(){ 
   return 1;
});

that would output

"return 1;"

How can this be done easily (for example without doing fopen of the source file, finding a source line, parsing etc.)?

Hm I think you have to write your PHP code as string cause every statement you write as such one gets interpreted by PHP. So you hvae no chance to fetch it and use it as "plain code". — TiMESPLiNTER, Oct 31 '13 at 10:37
@AlmaDo using runkit is also considered a dark side of unit-testing, I know — Artjom Kurapov, Oct 31 '13 at 10:39
Why don't use combinaison of eval and call_user_func() ? eval("call_user_func('yourfunction)") — BENARD Patrick, Oct 31 '13 at 10:52
I don't have a PHP instance with runkit installed to test this, but I *think* http://3v4l.org/EQd35 will work. Note that I am emphatically **not** *recommending* it, but I think it will work for your specific use case (note that it will not work if you just eval() it) — DaveRandom, Oct 31 '13 at 10:55
@ArtjomKurapov Working on a better version, doesn't play as nice as I'd like with arguments at the moment — DaveRandom, Oct 31 '13 at 11:19

score 4 · Accepted Answer · answered Oct 31 '13 at 11:41

NOTE: I do not like this solution and I would not recommend it to anyone for anything, but it does solve the problem set out in the question.

class CallableStringifier
{
    private static $callables = array();

    public static function stringify($callable)
    {
        $id = count(self::$callables);
        self::$callables[$id] = $callable;
        return 'return ' . __CLASS__ . "::call($id, func_get_args());";
    }

    public static function call($id, $args)
    {
        return call_user_func_array(self::$callables[$id], $args);
    }
}

This will work for your specific use case (which is essentially create_function()). It will not work if you just eval() it, because it relies on being inside a function context.

Example:

$func = create_function('$arg1', CallableStringifier::stringify(function($arg1) {
    return $arg1;
}));

echo $func(1); // outputs 1

See it working

Thanks. Although people should keep in mind that this doesn't really generate a true method body text, because it depends on current php process and whatever is stored in CallableStringifier::$callables. So if someone wants to write generated code in DB to be executed later, its not a good idea (not to mention its not a good idea to do it at all). But for current automated testing purposes its more efficient than reading file source — Artjom Kurapov, Oct 31 '13 at 11:47
Addendum: following on from the previous comment, if your *are* trying to "write generated code in DB to be executed later", you need to take a long, hard look at your application design ;-) — DaveRandom, Oct 31 '13 at 11:52

score 1 · Answer 2 · answered Oct 31 '13 at 11:21

Wrote a not-so efficient function.. (doesn't take into account arguments)

/**
 * Converts method code to string by reading source code file
 * Function brackets {} syntax needs to start and end separately from function body
 *
 * @param Callable $callable method to deevaluate
 *
 * @return string
 */
public function callableToString($callable) {
    $refFunc = new ReflectionFunction($callable);
    $startLine = $refFunc->getStartLine();
    $endLine   = $refFunc->getEndLine();

    $f      = fopen($refFunc->getFileName(), 'r');
    $lineNo = 0;

    $methodBody = '';
    while($line = fgets($f)) {
        $lineNo++;
        if($lineNo > $startLine) {
            $methodBody .= $line;
        }
        if($lineNo == $endLine - 1) {
            break;
        }
    }
    fclose($f);

    return $methodBody;
}

Convert php code to string, opposite to eval()

2 Answers2

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