[perl #58290] <prior> not implemented in rules in Rakudo

[Carl Mäsak]

# New Ticket Created by "Carl Mäsak"
# Please include the string: [perl #58290]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=58290 >

To match whatever the prior successful regex matched, use:

/ <prior> /

r30466:
$ ./perl6 -e 'my $s = "hello"; say $s ~~ /ll/; say $s ~~ /ll/' # works
ll
ll
$ ./perl6 -e 'my $s = "hello"; say $s ~~ /ll/; say $s ~~ / <prior> /'
# not implemented
ll
Unable to find regex 'prior'
Null PMC access in invoke()
[...]

This feature request is perhaps more accurately classified as
pertaining to PGE. Please re-tag as needed.

[Patrick R. Michaud]

On Sat, Aug 23, 2008 at 02:27:10AM -0700, Carl Mäsak wrote:
> To match whatever the prior successful regex matched, use:
>
> / <prior> /
>
> r30466:
> $ ./perl6 -e 'my $s = "hello"; say $s ~~ /ll/; say $s ~~ /ll/' # works
> ll
> ll
> $ ./perl6 -e 'my $s = "hello"; say $s ~~ /ll/; say $s ~~ / <prior> /'
> # not implemented
> ll
> Unable to find regex 'prior'
> Null PMC access in invoke()
> [...]
>
> This feature request is perhaps more accurately classified as
> pertaining to PGE. Please re-tag as needed.

...correct -- C<< <prior> >> is not yet implemented. I'm not
certain if it belongs in PGE or in Rakudo... I'm guessing that
<prior> needs to refer to the "prior successful regex" in a
statement-level context, as opposed to a regex context. For
example, if we interpret S05 literally then in the regex

/ <foo> <prior> /

it's pretty clear that C<< <foo> >> is the prior successful regex
matched, and I think that's not what is intended by C<< <prior> >>.
(If it is what is intended, then C<< <prior> >> becomes much
simpler. :-)

Pm

[Patrick R. Michaud via RT]

I've changed this ticket to indicate that it's waiting on spec
clarification as to the exact meaning of <prior> in regexes.

Pm

[Will Coleda via RT]

Since this ticket is about a clarification to the specification, it's been
migrated to the spec's issue queue:

https://github.com/perl6/roast/issues/8

--
Will "Coke" Coleda

[Will Coleda via RT]

Whoops, I meant:

https://github.com/perl6/specs/issues/5

--
Will "Coke" Coleda