Can I store a logical comparison in a string?

Question

I am trying to modularise a lengthy if..else function.

$condition = "$a < $b";
if($condition)
{
    $c++;
}

Is there any way of translating the literal string into a logical expression?

Answer 1

I am trying to modularise a lengthy if..else function.

You don't need to put the condition in a string for that, just store the boolean true or false:

$condition = ($a < $b);
if($condition)
{
    $c++;
}

the values of $a and $b may change between definition of $condition and its usage

One solution would be a Closure (assuming that definition and usage are happening in the same scope):

$condition = function() use (&$a, &$b) {
    return $a < $b;
}
$a = 1;
$b = 2;
if ($condition()) {
    echo 'a is less than b';
}

But I don't know if this makes sense for you without remotely knowing what you are trying to accomplish.

Answer 2

Use lambda if you know variables that are enough to determine result

$f = function ($a, $b) { return $a < $b; }

if ($f($x, $y)){}

Answer 3

you could do this using eval. not sure why you wouldn't just evaluate the condition immediately, though.

Answer 4

<?php
     $a=0;
     $b=1;
    function resultofcondition()
    {
        global $a,$b;
        return $a<$b;
    }
    if(resultofcondition()){
        echo " You are dumb,";
    }else{
        echo " I am dumb,"; 
    }
    $a=1;
    $b=0;
    if(resultofcondition()){
        echo " You were correct.";
    }else{
        echo " in your face.";
    }
?>

Indeed thanks for commenting that out, was missing the GLOBAL parameter, for those who voted down, what would that code output? ¬_¬ w/e have fun xD