Substitutions return Bools, not the resulting Str in Rakudo #2325

p6rt · 2011-01-11T21:35:00Z

Migrated from rt.perl.org#82108 (status was 'resolved')

Searchable as RT82108$

p6rt · 2011-01-11T21:35:01Z

From @masak

<masak> rakudo: sub y2i(

Extra open brace or missing close brace

$adjective is copy) { s/y$

/i/ given $adjective }; sub compare($adjective) { [$_, .&y2i ~ "er", .&y2i ~ "est"].fmt("%s", ", ") given $adjective }; say compare("funny") <p6eval> rakudo ea8c88: OUTPUT«funny, funnier, funniest␤» <tadzik> s/y$/i/ given $adjective – nice one <tadzik> but why not just

a d j e c t i v e s / y

/i/?
<masak> rakudo: sub y2i($adjective is copy) {

a d j e c t i v e s / y

/i/ };
sub compare($adjective) { join(", ", $adjective, $adjective.&y2i ~
"er", $adjective.&y2i ~ "est") }; say compare("funny")
<p6eval> rakudo ea8c88: OUTPUT«funny, Bool::Trueer, Bool::Trueest␤»
<masak> o.O
<jnthn> lol
* masak submits rakudobug
<jnthn> masak: Is it bug?
<masak> jnthn: I declare it a bug.
<jnthn> rakudo: my $x = "lol"; say $x ~~ s/o/0/;
<p6eval> rakudo ea8c88: OUTPUT«Bool::True␤»
<masak> based on tadzik's expectations, and the lack of spec.
<jnthn> That's...curious. :)
<tadzik> it certainly isn't DWIM
<jnthn> No
<jnthn> wtf. :/
<jnthn> rakudo: my $x = "lol"; say ($x ~~ s/o/0/).WHAT;
<p6eval> rakudo ea8c88: OUTPUT«Bool()␤»
<jnthn> Wow
<jnthn> I thought it was doing something with a match object that it
was getting back somehow
<jnthn> But...not even that.
<masak> definitely something for RT.
<jnthn> aye
<jnthn> Not sure what the spec is, but the above outcome is awfulest.
<moritz_> p5 people want to write if $x ~~ s/foo/bar/ { ... }
<masak> I understand moritz_' explanation, but I don't like it.
<tadzik> anyways, won't Match object evaluate to true anyway?
<tadzik> and if the match fails, there will be no object, no?
<jnthn> Yes
<tadzik> jnthn: good too
<masak> tadzik: I don't want it to return the match object. I'd like
it to return the resulting Str.
<masak> tadzik: if it returned the match object in my case above, it'd
stringify to 'y'
<jnthn> masak: I'm sure you know the counter case though. $x = 'x'; if
$x ~~ s/x// { ... }
<masak> right. [22:31]
<jnthn> It successfully substituted, but the resulting string is empty
and thus false.
<masak> I see that.
<jnthn> Maybe we just gotta choose our wart.
<masak> and an obvious patch to that would be to do 'but True' on the Str...
<masak> ...but I am reluctant to propose that.
<jnthn> I was gonna suggest that but then didn't because I worry about
it propagating, or confusion over "the return value of it is now true
but $x isn't...wtf" :)
<masak> right.
<jnthn> And because I don't really want to create a mixed-in string
for every substitution.
<jnthn> Given that but is a clone.
<masak> nodnod
<jnthn> (yes, it'd re-use the string buffer, but still...)
<masak> honestly, I could live with the Str sometimes boolifying to false.
<masak> that might even come in handy once in a while.
<jnthn> True
<masak> while s/(.)$// { ... }
<jnthn> I can imagine use cases where that's actually nice.

p6rt · 2011-10-08T21:20:46Z

From @coke

Same(ish) behavior in rakudo 33f1cf.

--
Will "Coke" Coleda

p6rt · 2011-10-08T21:20:46Z

@coke - Status changed from 'new' to 'open'

p6rt · 2014-02-26T01:23:38Z

From @coke

On Sat Oct 08 14:20:46 2011, coke wrote:

Same(ish) behavior in rakudo 33f1cf.

And 974d00.
--
Will "Coke" Coleda

p6rt · 2014-07-22T20:26:16Z

From @peschwa

On Tue Feb 25 17:23:38 2014, coke wrote:

On Sat Oct 08 14:20:46 2011, coke wrote:

Same(ish) behavior in rakudo 33f1cf.

And 974d00.

A PR for this exists at [1].

[1] rakudo/rakudo#295

p6rt · 2014-07-23T02:24:02Z

From @peschwa

On Tue Jul 22 13:26:16 2014, peschwa@gmail.com wrote:

On Tue Feb 25 17:23:38 2014, coke wrote:

On Sat Oct 08 14:20:46 2011, coke wrote:

Same(ish) behavior in rakudo 33f1cf.

And 974d00.

A PR for this exists at [1].

[1] rakudo/rakudo#295

[1] and onwards has some discussion on this issue. The spec didn't seem completely clear on this, but has been updated in [2]. The thus specified behavior is implemented in [3]. There's two tests in S05-substitution/subst.t that will have to be update to match the new behavior.

[1] http://irclog.perlgeek.de/perl6/2014-07-22#i_9064394
[2] Raku/old-design-docs@eca5f2f2df
[3] rakudo/rakudo#295

p6rt · 2015-02-09T06:45:59Z

From @Mouq

The current behavior is for s/// to return the match object of what was matched to be substituted for, per spec:

$ perl6 -e'sub y2i($adjective is copy) { $a d j e c t i v e s / y$ /i/ }; sub compare($adjective) { join(", ", $adjective, $adjective.&y2i ~ "er", $adjective.&y2i ~ "est") }; say compare("funny")'
funny, yer, yest

(in this case, .subst or .=subst is probably what is really wanted)

As peschwa++ said, this is tested against in S05-substitution/subst.t

Marking this issue as resolved :)

On Tue Jul 22 19:24:02 2014, peschwa@gmail.com wrote:

On Tue Jul 22 13:26:16 2014, peschwa@gmail.com wrote:

On Tue Feb 25 17:23:38 2014, coke wrote:

On Sat Oct 08 14:20:46 2011, coke wrote:

Same(ish) behavior in rakudo 33f1cf.

And 974d00.

A PR for this exists at [1].

[1] rakudo/rakudo#295

[1] and onwards has some discussion on this issue. The spec didn't
seem completely clear on this, but has been updated in [2]. The thus
specified behavior is implemented in [3]. There's two tests in S05-
substitution/subst.t that will have to be update to match the new
behavior.

[1] http://irclog.perlgeek.de/perl6/2014-07-22#i_9064394
[2] Raku/old-design-docs@eca5f2f2df
[3] rakudo/rakudo#295

p6rt · 2015-02-09T06:46:00Z

@Mouq - Status changed from 'open' to 'resolved'

p6rt closed this as completed Feb 9, 2015

p6rt added the Bug label Jan 5, 2020

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Substitutions return Bools, not the resulting Str in Rakudo #2325

Substitutions return Bools, not the resulting Str in Rakudo #2325

p6rt commented Jan 11, 2011

p6rt commented Jan 11, 2011

p6rt commented Oct 8, 2011

p6rt commented Oct 8, 2011

p6rt commented Feb 26, 2014

p6rt commented Jul 22, 2014

p6rt commented Jul 23, 2014

p6rt commented Feb 9, 2015

p6rt commented Feb 9, 2015

Substitutions return Bools, not the resulting Str in Rakudo #2325

Substitutions return Bools, not the resulting Str in Rakudo #2325

Comments

p6rt commented Jan 11, 2011

p6rt commented Jan 11, 2011

From @masak

p6rt commented Oct 8, 2011

From @coke

p6rt commented Oct 8, 2011

p6rt commented Feb 26, 2014

From @coke

p6rt commented Jul 22, 2014

From @peschwa

p6rt commented Jul 23, 2014

From @peschwa

p6rt commented Feb 9, 2015

From @Mouq

p6rt commented Feb 9, 2015