[perl #132120] [REGEX] Accessing captures from another capture fails a match
On Mon, 18 Sep 2017 09:46:50 -0700, sml...@gmail.com wrote: > This ticket can IMO be closed as 'rejected', but I'll leave it open > for now in case I missed something obvious or in case you want to turn > it into an RFC or similar. > > > --- > [1] http://design.perl6.org/S05.html#Subpattern_captures I just didn't know of this feature. Thanks for clarifying. Rejecting
[perl #132120] [REGEX] Accessing captures from another capture fails a match
On Mon, 18 Sep 2017 09:46:50 -0700, sml...@gmail.com wrote: > This ticket can IMO be closed as 'rejected', but I'll leave it open > for now in case I missed something obvious or in case you want to turn > it into an RFC or similar. > > > --- > [1] http://design.perl6.org/S05.html#Subpattern_captures I just didn't know of this feature. Thanks for clarifying. Rejecting
[perl #132120] [REGEX] Accessing captures from another capture fails a match
On Mon, 18 Sep 2017 09:00:54 -0700, c...@zoffix.com wrote: > IRC: https://irclog.perlgeek.de/perl6/2017-09-18#i_15181575 > > We can use $0 here to refer to previous capture and regex matches: > m: say "11" ~~ /(\d)[$0]/ > rakudo-moar 48a84d: OUTPUT: «｢11｣ 0 => ｢1｣» > > But if we capture that match, the match fails: > m: say "11" ~~ /(\d)([$0])/ > rakudo-moar 48a84d: OUTPUT: «Nil» Not a bug. Each `( )` capture represents a subpattern¹ that builds its own Match object, and inside the subpattern, `$/` refers to this subpattern's Match (which in your case doesn't have any captures) and not to the parent pattern's Match (which has the capture you meant to access). (PS: Remember that `$0` is just an alias for `$/[0]`.) I don't think there's a built-in way to access a parent pattern's Match object - you'll have to manually pass on the object in a variable or similar, like you already discovered in the linked IRC log. This ticket can IMO be closed as 'rejected', but I'll leave it open for now in case I missed something obvious or in case you want to turn it into an RFC or similar. --- [1] http://design.perl6.org/S05.html#Subpattern_captures
[perl #132120] [REGEX] Accessing captures from another capture fails a match
# New Ticket Created by Zoffix Znet # Please include the string: [perl #132120] # in the subject line of all future correspondence about this issue. # https://rt.perl.org/Ticket/Display.html?id=132120 > IRC: https://irclog.perlgeek.de/perl6/2017-09-18#i_15181575 We can use $0 here to refer to previous capture and regex matches: m: say "11" ~~ /(\d)[$0]/ rakudo-moar 48a84d: OUTPUT: «｢11｣ 0 => ｢1｣» But if we capture that match, the match fails: m: say "11" ~~ /(\d)([$0])/ rakudo-moar 48a84d: OUTPUT: «Nil»
