[SOLVED] Sort of a unique problem

[dbo]

I'm writing some code that allows users to enter in a regex string and then calls preg_match. Using preg_match to validate a regex string before calling preg_match just seems weird to me, so what I'd like to do is error handle preg_match... is there a way I could emulate functionality thats like:

 

preg_match(..., ...) || return false;

 

See I don't want to stop executing the script at all, just want to treat that function breaking as false and report an error message. I'm sure I could pull it off with a try/catch but that's not something that would work in PHP4. Soooo what other suggestion do you guys have?

[Jessica]

I don't understand the problem...why not do

if(!preg_match(..., ...)){
  print 'error';
}

[dbo]

uh, that's a completely different issue. I'm talking about error handling preg match due to input that might break it.

[MadTechie]

I'm not 100% sure what your looking for..

 

but if you wish to check if the regex was valid then maybe use preg_last_error,

 

example

<?php
$RegEx = "/\s/si";
$String = "testing";
$data = @preg_replace($RegEx, $String);

switch(preg_last_error())
{
case 0:
//no error
break;
case 1:
echo "PREG_INTERNAL_ERROR";
break;
case 2:
echo "PREG_BACKTRACK_LIMIT_ERROR";
break;
case 3:
echo "PREG_RECURSION_LIMIT_ERROR";
break;
case 4:
echo "PREG_BAD_UTF8_ERROR";
break;

}
?>

[dbo]

That's got potential. It seems like just in general there ought to be a way to do:

 

func() || return false;

 

[Jessica]

"preg_match() returns FALSE if an error occurred."

So,

if(preg_match(your input) === false){
print 'error';
}

 

You only use || inside a conditional statement, you don't just say do this or this. You say if this, do this, which can mean if this fails, do this. Same thing.

[dbo]

Take the following code for example:

 

    $matches = preg_match("/balh", "10");
    if( $matches != 0 ) echo "woot!";

 

Naturally ther errors out because I'm missing my closing / in the regex. However, it yields this error message:

 

Warning: preg_match() [function.preg-match]: No ending delimiter '/' found in /var/www/test.php on line 20. Are you suggesting that I compress the error message with @ and it will return false?

[Jessica]

Well, try it and see

[dbo]

Laugh, that seems like such a hack... but I think it will work. I still think i should be able to func() || return false!

[Jessica]

how can it return if it's not inside a function? If you really want it to return a value make a function. But you have to use the if else construct, like I said. It's the same thing, just with the PROPER statements.

[dbo]

I could make it work with a global variable! lol