# New Ticket Created by yary
# Please include the string: [perl #66606]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=66606 >
yary perl6: (my @random_numbers).push: int 10.rand for ^3; say
@random_numbers.join: ' ';
12:36 p6eval ..STD_red…
12:36 p6eval ..pugs: OUTPUT«3 4 3»
12:36 p6eval ..rakudo 77f9d7: OUTPUT«Lexical '@random_numbers' not found»
12:37 yary Methinks pugs wins in that statement- anyone think that bug
looks familiar? Or should I submit?
...pmichaud rakudo: my @random_numbers; @random_numbers.push(
int(10.rand) ) for ^3; say @random_numbers.join(' ');
12:43 p6eval rakudo 77f9d7: OUTPUT«3 3 9»
...12:55 pmichaud it's the declaration of the "my" as modified by
the "for"
# bug here vvv
12:55 pmichaud rakudo: my $x = 1 for ^3; say $x;
12:55 p6eval rakudo ba09b2: OUTPUT«Lexical '$x' not found»
# bug there ^^^
12:55 pmichaud the "for" modifier is imposing a block on what it
modifies.
#discussion
yary So the next question is, does it make sense for a lexical
declaration in an implied block (no curlies) to have a lifetime
limited to that implied block?
13:02 PerlJam What does S04 say about it? (if anything)
13:16 pmurias yary: what do you mean by an implied block?
13:17 pmurias yary: generally only curlies introduce a new lexical scope
13:18 pmichaud rakudo: $_ = 'hello'; .say for ^3; say $_;
13:18 p6eval rakudo ba09b2: OUTPUT«012hello»
13:18 pmichaud pmurias: the ".say" has an implied block around it.
13:19 yary Rakudo's behavior suggests that a "for" modifier at the end
of a statement which includes a declaration gives a lexical scope to
that declaration, and then the variable is invisible outside
13:19 yary sorry for the verbosity
13:20 pmurias yary: verbosity is better then ambiguity
13:21 pmichaud it's very possible that implying a block on the lhs
isn't correct, and that we need to be making a temporary $_ or
something.
13:22 pmichaud at any rate, the $_ that is used on the lhs of a for
modifier isn't the same as the $_.
13:22 pmichaud at any rate, the $_ that is used on the lhs of a for
modifier isn't the same as the $_ outside of the for modifier.
13:25 yary That much (about $_) I understand from p5... haven't
digested S04 yet, but I'll submit this as a bug for folks to ponder
and accept/reject
13:28 pmurias there is a "Remeber, no implicit block scopes." sentence
in S04, although in a different context
13:28 pmichaud Yes -- a bit later it talks about the handling of $_
and the for modifier.
13:28 pmichaud It says to get to the outer $_ one uses OUTER::<$_>
13:29 pmichaud which will be a little weird, since it means that
OUTER::<$foo> would refer to a different scope from OUTER::<$_> if
used inside a for modifier.
13:29 TimToady that's true for any lexical in any lexical scope
13:30 TimToady if $_ is declared internally and $foo externally
13:30 pmichaud TimToady: We're looking at the case of:
13:30 pmichaud say $_ for ^3;
13:30 TimToady yes, I've been thinking about it
13:30 pmichaud okay.
13:30 TimToady the spec only requires a private copy for $_ currently
13:31 pmichaud correct.
13:31 TimToady doesn't require a block
13:31 pmichaud I think the use of a block might've been a Rakudo
shortcut.
TimToady we could say it is implciit
13:31 TimToady but...
13:31 TimToady we can't really allow $^a to pay attention to implicit
{}
13:31 pmichaud interestingly, I'm not sure that it does in Rakudo's
case.
13:32 pmichaud rakudo: say $^a for ^3;
13:32 p6eval rakudo ba09b2: OUTPUT«too few arguments passed (0) - 1
params expectedin Main (/tmp/jBX8Gm96fv:0)»
13:32 TimToady well, could use a better error
13:32 pmichaud sure.
13:32 pmichaud rakudo: { say $^a for ^3 }('hello');
13:32 p6eval rakudo ba09b2: OUTPUT«hellohellohello»
13:32 moritz_ std: say $^a for ^3;
13:32 p6eval std 27084: OUTPUT«ok 00:02 38m»
... TimToady this is also all related to $a ?? my $bar !! my $baz
13:34 TimToady thunks aren't quite blocks
etcetera!
