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Asked: 2026-06-16T06:06:40+00:00

I have some code that looks like this. eval(‘$ruleTrue = ‘.{$value} {$operator} {$value2};); I

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I have some code that looks like this.

eval('$ruleTrue = '."{$value} {$operator} {$value2};");

I am pulling mostly numeric values from a database and comparing them with other numeric values. The operator comes from a database as well. Possible operators are <,>,==.

Well when comparing ints and floats this works perfectly. BUT when comparing strings it breaks. For instance..

WORKS:
5 > 4
$ruleTrue = true

Doesn’t Work Right:
John-Adams == Alice
$ruleTrue = true <— WHY? Because John is not == to Alice.

For some reason my $ruleTrue variable is being returned as true when comparing strings.

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1 Answer

  1. Editorial Team

    You’re trying to evaluate this code:

    $ruleTrue = John == Alice;

    John and Alice aren’t strings, they’re undefined constants. You want to put quotes around them. But be careful, because if your users are able to edit those fields in your database, they could find a way of unquoting the strings and executing their own php code, which could be disastrous. Eval is very unsecure that way, and you probably shouldn’t be using it.

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