Why no RE match of A AND B?

[Paddy]

Paddy wrote:
> 
> Just looking through the docs to confirm it and their seems to be no 
> regular expression construct that matches 'A and B' - an equivalent to 
> the '|' character that matches A or B
> To paraphrase the documentation it could be documented as:
> 
>   "&"
> A&B, where A and B can be arbitrary REs, creates a regular expression 
> that will match both A and B in any order. An arbitrary number of REs 
> can be separated by the "&" in this way. This can be used inside groups 
> as well. REs separated by "&" are tried in arbitrary order, the 
> beginning of the first matching branch up to the end of the last branch 
> that allows the complete pattern (all branches) to match is considered 
> the span of the match.
> 
> I envision it being used where a string is accepted at present if it 
> matches multiple REs.
> The REs could be rewritten as r"<RE#1>&<RE2>&<RE3>...".
> 
> The use of "&" could be supported by more efficient, (simultaneous?),  
> matching of all branches of the "&" construct - if such algorithms exist!
> 
>  Just an idea,
> 
>   Paddy.
> 

Thanks all, for your input so far.

Having thought of it, and seen the posts on if it is necessary or not, or needed or not; 
it seems a bit odd that we are left with one of the few places where the or 'operation' is 
defined, but the orthogonal and 'operation' is not ?!

Paddy.