You could eval{qr /something/};.

Thanks pbeckingham, this was exactly the answer I needed. The key here was being able to test *on the fly*, which this accomplishes well.

Let's re-phrase the question to: Is there a way that I can test prior to running a progrgam whether or not a regular expression will compile.

The answer is Yes, use the -c flag when invoking perl. You can use: Perl -c myprogram, or you might make the program read in the regex from an external file ... possibly specifying which file on the command line. Then you only have to test the regex file: Perl -c regexfile.

That doesn't work if the regex is passed in as a parameter, say if you are doing something screwy like loading it from a database. The way to do that is probably to check at startup, or otherwise write another program, to run eval-block type tests on each of the many regexes that can be imported.

In a worst case scenario, isn't this kind of asking for trouble? What if someone wanted to insert malicious code into this running script? Granted, I really don't know the full implications of using an Eval block to run unknown code, but wouldn't using Reval be a bit more desirable with something like this? I'm just thinking in terms of reducing the amount of risk present to a computer.

If I'm way off base here, I'd appreciate some clarification on this. Whenever I thought I had an excuse to use an Eval, I always found a much better way through refactoring. :)

Agreed. Running eval on untrusted input is a recipe for disaster!

Using Taint would be a very good idea, although I'm not sure how you'd make a regex that correctly extracts a regex :-)