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.