Hi, I also think that adding the support would be very useful. However, I would definitely avoid PCRE and backreference support. I think the best solution would be to just add a basic and efficient NFA-based implementation (the defacto original implementation for Unix). For more information about the correct way to implement RE: https://swtch.com/~rsc/regexp/
As for the API itself, I agree with Elias that maybe a simple interface is the way to go. I would also prefer not to have any support for modifiers (not even IGNORECASE) and definitely avoid the MULTILINE horror. If we opt for the NFA implementation then, the builtin ⎕Regex (or ⎕RE) could be universally used not only for strings but for numeric data as well. That, in conjuction with APL arrays, would ultimately be a killer feature (I am not aware of such a feature in other languages). Best, Giuseppe Cocomazzi http://sbudella.altervista.org On Wed, Sep 20, 2017 at 5:59 AM, Elias Mårtenson <loke...@gmail.com> wrote: > On several occasions, I have felt that built-in regex support in GNU APL > would be very helpful. > > Implementing it should be rather simple, but I'd like to discuss how such an > API should look in order for it to be as useful as possible. > > I was thinking of the following form: > > regex ⎕Regex string > > The way I envision this to work, is to have the function return ⍬ if there > is no match, or a string containing the match, if there is one: > > 'f..' ⎕Regex 'xzooy' > ┏⊖┓ > ┃0┃ > ┗━┛ > 'f..' ⎕Regex 'xfooy' > 'foo' > > If the regex has subexpressions, those matches should be returned as > individual strings: > > '([0-9]+)-([0-9]+)-([0-9]+) '⎕Regex '2017-01-02' > ┏→━━━━━━━━━━━━━━━┓ > ┃"2017" "01" "02"┃ > ┗∊━━━━━━━━━━━━━━━┛ > > This would be a very useful API, and reasonably easy to implement by simply > calling into the standard regcomp() call: > http://pubs.opengroup.org/onlinepubs/009695399/functions/regcomp.html > > What do you think? Is this a reasonable way to implement it? Any suggestions > about alternative API's? > > Regards, > Elias