benjohn
3/12/2006 10:19:00 AM
On 12 Mar 2006, at 09:58, Dan Kohn wrote:
> You'll generally get a better answer if you include an example in your
> question. Also, that link didn't work.
>
> If you're asking how to apply two regexps, you can use the scan method
> to get the results in arrays, and then intersect them with &.
>
> string ="hello world"; puts string.scan(/.../) & string.scan(/..l/)
I think he's trying to do this...
If you have a regular expression, R, then there is a (potentially
infinite) set S(R) of input strings that it will match.
Given two regular expressions, R1 and R2, you can find the strings
that match either regular expression:
S(R1) & S(R2)
He now wants to find a regular expression Ri such that:
S(Ri) = S(R1) & S(R2)
And he's looking for an algorithm that will calculate Ri given R1 and
R2. I think :)
Given, say:
R1 = /hell/
R2 = /ello/
then I think that Ri = /hello/
:) It could, perhaps, be a ruby quiz.