Fixing the API of std.regex

[Brad Anderson]

On Tuesday, 12 March 2013 at 09:41:08 UTC, Dmitry Olshansky wrote:
> *Spoiler*: let's slowly deprecate "g" option in std.regex in a 
> few years or with any luck a bit faster. The better replacement 
> is proposed.
>
> For better or worse the current API has retained a (high) level 
> of compatibility with the old API. That means I've missed the 
> chance to fix it when I could, and here is the prime problem 
> (the hardest) I have with it:
>
> foreach(m; match("bleh-blah", "bl[ea]h"))
> {
> 	writeln(m.hit);
> }
>
> The "quiz" is - how many lines will this print?
>
> The current answer is 1. And that the right solution for all 
> matches is:
>
> foreach(m; match("bleh-blah", regex("bl[ea]h","g"))
> {
> 	writeln(m.hit);
> }
>
> Which is not only looks unsightly but also confuses operation 
> option (find _all_ vs find _first_) with property of a pattern 
> (like case-insensitivity is). And if regex pattern is defined 
> elsewhere it could easily introduce a bug (albeit one that's 
> easy to track, "usually").
>
> To underline the point: std.regex.splitter doesn't take "g" 
> flag into account at all (it makes no sense there).
>
> I've pondered a couple of solutions in a bug report by 
> bearophile:
> http://d.puremagic.com/issues/show_bug.cgi?id=7260
>
> After all of these ideas born and discarded, here is what I 
> believe is the way forward out of this mess:
>
> Make "g" indicates only the intended _default_ search mode of 
> this pattern (global - first match).
>
> User is free to override this default explicitly and in fact 
> encouraged to do so. The idea of default search mode attached 
> to the regex pattern is marked as discouraged.
>

I nearly always forget to include "g" so I welcome any changes 
that make make "g" go away.  match.first/match.all/etc. is easy 
to read and the intent is right up front which I prefer over 
tacking a flag argument on the end.  matchFirst/matchAll/etc. is 
fine too but not nearly as cool :).