Compare regular expressions

[Thomas Dybdahl Ahle]

Den Mon, 16 Apr 2007 11:50:40 +0200 skrev Thomas Dybdahl Ahle:

> Hi, I'm writing a program with a large data stream to which modules can
> connect using regular expressions.
> 
> Now I'd like to not have to test all expressions every time I get a
> line, as most of the time, one of them having a match means none of the
> others can have so.
> 
> But ofcource there are also cases where a regular expression can
> "contain" another expression, like in: "^strange line (\w+) and (\w+)$"
> and "^strange line (\w+) (?:.*?)$" in which case I'd like to first test
> the seccond and only if it mathces test the seccond.
> 
> Do anybody know if such a test is possible? if exp0.contains(exp1): ...

I found this link: http://terpstra.ca/compare.html which seams to compare 
expressions. Not python expressions though.
Sadly it writes nothing about the way it does the thing, and if it will 
always work.