<mumble> anyone who loves grep and hates perl (and i hope java too) can't be all bad </mumble>
using apl like syntax is good aaa' ⎕REX['s'] 'bbb' what would monadic ⎕REX['s'] 'bbb' return? On Wed, 20 Sep 2017 21:47:29 +0200 Juergen Sauermann <juergen.sauerm...@t-online.de> wrote: > Hi Elias, > > I am generally in favour of supporting regular expressions in GNU APL. > > We should do that in a way that is compatible with the way in which the most > commonly used libraries > do that (even if they are lacking some features that more exotic libraries > may have. Unfortunately I do not > have a full overview of all (or even any) existing libraries. I personally > love grep and hate perl (the latter not > only because of their regexes). > > I would like to avoid constructs like s/aaa/bbb/ where operations are kind of > text-encoded into strings. > That is, IMHO, a hack-ish programming style and should be replaced by a more > APL-alike syntax such as > 'aaa' ⎕REX['s'] 'bbb' or maybe 's' ⎕REX 'aaa' 'bbb'. > > Or, if the number of operations is small (perl seems to have only 2, not > counting the translate which is already > covered by other APL functions), then we could also have different > ⎕-functions for them and thus avoiding a > third argument. > > Everybody else, please feel invited to join the discussion. > > Best Regards, > Jürgen Sauermann > > > On 09/20/2017 05:59 AM, Elias Mårtenson 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 >
