Re: patch adding new regexp functions

On Thu, 15 Feb 2007, Alvaro Herrera wrote:

> Jeremy Drake wrote:
>
> > The functions added are:
> > * regexp_split(str text, pattern text) RETURNS SETOF text
> >   regexp_split(str text, pattern text, flags text) RETURNS SETOF text
> >    returns each section of the string delimited by the pattern.
> > * regexp_matches(str text, pattern text) RETURNS text[]
> >    returns all capture groups when matching pattern against string in an
> >    array
> > * regexp_matches(str text, pattern text, flags text) RETURNS SETOF
> >     (prematch text, fullmatch text, matches text[], postmatch text)
> >    returns all capture groups when matching pattern against string in an
> >    array.  also returns the entire match in fullmatch.  if the 'g' option
> >    is given, returns all matches in the string.  if the 'r' option is
> >    given, also return the text before and after the match in prematch and
> >    postmatch respectively.
>
> I think the position the match is in could be important.  I'm wondering
> if you could define them like
>
> create type re_match(match text, position int)
> regexp_split(str text, pattern text) returns setof re_match

So it looks like the issues are:
1. regexp_matches without flags has a different return type than
   regexp_matches with flags.  I can make them return the same OUT
   parameters, but should I declare it as returning SETOF when I know
   for a fact that the no-flags version will never return more than one
   row?

2. regexp_split does not represent the order of the results.  I can do
   something like:

 regexp_split(str text, pattern text[, flags text], OUT result text, OUT
startpos int) RETURNS SETOF record;

It could also have the int being a simple counter to represent the
relative order, rather than the position.


Thoughts?  Do these changes address the issues recently expressed?




--
I have yet to see any problem, however complicated, which, when looked
at in the right way, did not become still more complicated.
        -- Poul Anderson