How to Dynamically Generate String Validation?

Question

Does anyone know of a library (preferably php) or algorithm for auto-generating regex's from some common descriptions?

For example, have a form with the possible options of:

• Length (=x, between x & y, etc)
• Starts with
• Ends with
• Character(s) x(yz) at index i
• Specify one or more alternative behavior based on the above
• And so on..

The idea is that for certain data entities in a system, you'll be able to go to a form and set this criteria for a data field. Afterward, any time that data field for that type of data entity is entered, it will be validated against the regex.

This seems like it could grow into a complex problem though, so I'm not expecting anyone to solve it as a whole. Any suggestions are much appreciated.

Answer 1

I have found txt2re, but it doesn't quite go all the way as it only generates single regex's and the whole site code might not be available.

Answer 2

This doesn't take care of all of your issues but the PHP Filter functions may be a good starting place.

Answer 3

Would simple globs be enough? For globs it's just a matter of replacing * with .* and adding ^ and $. Or may be Excel-style patterns? It should not be too hard to write a regexp generator for simple rules like this...

My point is, adjust your requirements to simplify the code, and then may be add more features as needed.