Either binding an array to a list containing the array itself should work consistently or not at all in Rakudo

[p6rt]

Migrated from rt.perl.org#87034 (status was 'open')

Searchable as RT87034$

[p6rt]

From @masak

<masak> rakudo​: my @​foo := 1..3, @​foo; .say for @​foo[^10]
<p6eval> rakudo 792e86​: OUTPUT«1␤2␤3␤1␤2␤3␤1␤2␤3␤1␤»
<masak> this is what I expect.
<pmurias> sorear​: explain what you mean by the second thing?
<masak> rakudo​: my @​foo := 1..3, (@​foo Z+ 100); .say for @​foo[^10]
<p6eval> rakudo 792e86​: OUTPUT«1␤2␤3␤101␤Any()␤Any()␤Any()␤Any()␤Any()␤Any()␤»
<masak> that... is not.
<masak> can we rely on array binding of the above kind to work?
<masak> if yes, is the second eval an expression of a rakudobug?
<masak> if no, how are we supposed to explain that some cases work and
some not? :/
<sorear> masak​: I beleive so on both counts
* masak submits rakudobug
<sorear> I expect "1 2 3 Any() Any() ..." for both of them

[p6rt]

From @masak

On Fri Mar 25 14​:00​:30 2011, masak wrote​:

<masak> rakudo​: my @​foo := 1..3, @​foo; .say for @​foo[^10]
<p6eval> rakudo 792e86​: OUTPUT«1␤2␤3␤1␤2␤3␤1␤2␤3␤1␤»
<masak> this is what I expect.
<pmurias> sorear​: explain what you mean by the second thing?
<masak> rakudo​: my @​foo := 1..3, (@​foo Z+ 100); .say for @​foo[^10]
<p6eval> rakudo 792e86​:
OUTPUT«1␤2␤3␤101␤Any()␤Any()␤Any()␤Any()␤Any()␤Any()␤»
<masak> that... is not.
<masak> can we rely on array binding of the above kind to work?
<masak> if yes, is the second eval an expression of a rakudobug?
<masak> if no, how are we supposed to explain that some cases work and
some not? :/
<sorear> masak​: I beleive so on both counts
* masak submits rakudobug
<sorear> I expect "1 2 3 Any() Any() ..." for both of them

<sorear> masak​: ignore everything I've said in the last 12 minutes; I misread
your example as my @​foo := 1..3; @​foo; .say for @​foo[^10]
<masak> ah :)
<sorear> and I was WTFing at the rakudoinsanity
* masak adds that to the rakudobug

[p6rt]

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

[p6rt]

From @masak

<sorear> eagerly (without {} blocks) self-referential binding will never work
<sorear> because all occurrences of @​fib in the RHS will be resolved to the old
container, which is discarded by the binding
<sorear> eagerly self-referential *assignment* may work in some cases
<masak> rakudo​: my @​selfref := 1, 2, 3, @​selfref; .say for @​selfref[^10]
<p6eval> rakudo 792e86​: OUTPUT«1␤2␤3␤1␤2␤3␤1␤2␤3␤1␤»
<masak> sorear​: how come that works, then?
<sorear> masak​: rakudo's broken binding model
<masak> :(
<sorear> perl6​: my $x = 1; my $y := $x; $x := 3; say $y;
<p6eval> pugs, niecza v3-82-g1dc43eb​: OUTPUT«1␤»
<p6eval> ..rakudo 792e86​: OUTPUT«3␤»
<masak> that is indeed broken.
<masak> wow.

[p6rt]

From @moritz

On Fri Mar 25 14​:48​:47 2011, masak wrote​:

<masak> sorear​: how come that works, then?
<sorear> masak​: rakudo's broken binding model
<masak> :(
<sorear> perl6​: my $x = 1; my $y := $x; $x := 3; say $y;
<p6eval> pugs, niecza v3-82-g1dc43eb​: OUTPUT«1␤»
<p6eval> ..rakudo 792e86​: OUTPUT«3␤»
<masak> that is indeed broken.
<masak> wow.

That one is fixed now, and tested in S03-binding/scalars.t.

Can anybody comment on our current understanding of the array binding cases?

[p6rt]

From @usev6

Since Rakudo commit 3754356d8e this fails with X​::Syntax​::Variable​::Initializer​:

$ perl6-m -e 'my @​foo := 1..3, @​foo; .say for @​foo[^10]'
===SORRY!=== Error while compiling -e
Cannot use variable @​foo in declaration to initialize itself
at -e​:1
------> my @​foo := 1..3, @​⏏foo; .say for @​foo[^10]
  expecting any of​:
  term

In other words, binding an array to a list containing the array itself does not work at all. Therefore I'm closing this ticket as 'resolved'.

Test​: Raku/roast@dca1faef23

[p6rt]

From @usev6

Since Rakudo commit 3754356d8e this fails with X​::Syntax​::Variable​::Initializer​:

$ perl6-m -e 'my @​foo := 1..3, @​foo; .say for @​foo[^10]'
===SORRY!=== Error while compiling -e
Cannot use variable @​foo in declaration to initialize itself
at -e​:1
------> my @​foo := 1..3, @​⏏foo; .say for @​foo[^10]
  expecting any of​:
  term

In other words, binding an array to a list containing the array itself does not work at all. Therefore I'm closing this ticket as 'resolved'.

Test​: Raku/roast@dca1faef23

[p6rt]

@usev6 - Status changed from 'open' to 'resolved'

[p6rt]

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

[p6rt]

From @AlexDaniel

Reopened for now.

See RT #​121807 and RT #​125371 for more info. Basically, there will be no error after I'm done with everything.

In case of binding, @​foo will appear as Mu. Binding doesn't make much sense in this case, DIHWIDT.

(Mu Z+ 5) will error out normally.

On 2015-11-10 13​:59​:32, bartolin@​gmx.de wrote​:

Since Rakudo commit 3754356d8e this fails with
X​::Syntax​::Variable​::Initializer​:

$ perl6-m -e 'my @​foo := 1..3, @​foo; .say for @​foo[^10]'
===SORRY!=== Error while compiling -e
Cannot use variable @​foo in declaration to initialize itself
at -e​:1
------> my @​foo := 1..3, @​⏏foo; .say for @​foo[^10]
expecting any of​:
term

In other words, binding an array to a list containing the array itself
does not work at all. Therefore I'm closing this ticket as 'resolved'.

Test​: Raku/roast@dca1faef23

[p6rt]

From @AlexDaniel

By the way, there is a pull request​: rakudo/rakudo#1020

But the work on it is kinda stalled.

On 2017-02-17 04​:22​:51, alex.jakimenko@​gmail.com wrote​:

Reopened for now.

See RT #​121807 and RT #​125371 for more info. Basically, there will be
no error
after I'm done with everything.

In case of binding, @​foo will appear as Mu. Binding doesn't make much
sense in
this case, DIHWIDT.

(Mu Z+ 5) will error out normally.

On 2015-11-10 13​:59​:32, bartolin@​gmx.de wrote​:

Since Rakudo commit 3754356d8e this fails with
X​::Syntax​::Variable​::Initializer​:

$ perl6-m -e 'my @​foo := 1..3, @​foo; .say for @​foo[^10]'
===SORRY!=== Error while compiling -e
Cannot use variable @​foo in declaration to initialize itself
at -e​:1
------> my @​foo := 1..3, @​⏏foo; .say for @​foo[^10]
expecting any of​:
term

In other words, binding an array to a list containing the array
itself
does not work at all. Therefore I'm closing this ticket as
'resolved'.

Test​: Raku/roast@dca1faef23

[lizmat]

So what is the status now?