Jenda,

I'm not entirely sure what you mean by "underlying engine." My script does the evaluation--I'm not depending on any third-party tools. This has as much to do with the fact that I can rarely understand how to implement others' modules as anything. (Object-oriented code baffles me.)

The regex evaluation is fairly simple, and meant to allow virtually any arbitrary expression, with a few important exceptions such as not allowing the user to insert executable code into it. Giving the user freedom to enter his or her own regular expression is what makes the feature so attractive and powerful. There is no other way to properly find certain things without a good regex, and it would be impossible to pre-supply all potential regex forms that might be needed.

Users have several simple options at their disposal that do not require the evaluation of a regular expression. For example, they may select for case sensitivity, the matching of whole words (i.e. \bWord\b), or to enter their own word/text delimiters. But these options will be ignored if the user chooses to use his or her own regular expression--in which case the matching of whole words, etc., would be left entirely to the user's own regex.

As for "You should not look for dangerous stuff, you should check you only got safe stuff!", how would you propose to divide between these two? What defines "safe"? As with anything on this planet, even the safest of things can be made to be harmful when placed in the wrong hands. Because people could drown in water is no reason to withhold it and cause them to die of thirst!