Document $;

[ElenaMerelo]

The problem

The C<$;> variable is only in 5to6-perlvar doc.

Suggestions

It would be good if it had its own doc, in Variable.pod6 for instance

[lichtkind]

because its deprecated, see: #2632

[JJ]

Not really deprecated, it should throw an exception, but it does not: -- say "\$; is ", $; # OUTPUT: «$; is (Any)␤» When it's fixed, that behaviour should be documented anyway, maybe in perl5to6-variables El sáb., 2 mar. 2019 a las 22:10, Herbert Breunung (< notifications@github.com>) escribió:

…

because its deprecated, see: #2632 <#2632> — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#2642 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAAB9AU0YgowN3f3SPxl24as_sujmhOMks5vSui6gaJpZM4bakBw> .

-- JJ

[b2gills]

There is no $; variable in Perl6.

It is an anonymous state variable $, followed by the statement terminator ;.

my $a := $;    my $b := $; # two separate $ variables

$a = 1;
say $b; # (Any)

my $c := $_;    my $d := $_;

$c = 3;
say $d; # 3

say ++ $ for ^3
# 1
# 2
# 3

---

If you tried to use it in a string you get a compilation error.

" $; "
# ===SORRY!=== Error while compiling:
# Non-variable $ must be backslashed

---

So the only place it really makes sense to talk about it is in 5to6-perlvar.

[JJ]

Right. Some of the other variables, however, exist, even if they return Any.

[AlexDaniel]

According to the raku-golf-cheatsheet repo, there's only $/ and $! (+ anonymous state vars). $¢ is also mentioned but it's more internal and I don't know if it should be documented. Everything else is not a variable :)

[JJ]

The thing is that the specs for 6.d say:

Trying to use variables $;, $,, $., $\, $(, $),$<, $>, $/, $\, $[, $-, $+,

and $@ throws X::Syntax::Perl5Var So it's not so much a matter of what degree of existence they have; they do exist enough to be documented if that's the case. Problem is I don't see how we could actually use $; of for that matter $, Using any one of them behaves as @b2gills says.

[AlexDaniel]

Oh, the parser does attempt to detect the use of these variables. For example:

$; = 42

===SORRY!=== Error while compiling -e
Unsupported use of $; variable; in Perl 6 please use real multidimensional hashes
at -e:1
------> $;⏏ = 42

[JJ]

Then that's what should be documented, I guess.

[AlexDaniel]

Not really, no. IMO these error messages shouldn't even be enabled by default (you should only see them with use training-wheels <perl5>).

[coke]

Given that this is only part of the 5 to 6 training wheels, I think it's OK that it's only listed on the 5 to 6 page, and that it's not indexed. (it is findable if you use the search site option). The documentation on this page says:

The subscript separator variable is not included in Perl 6. Frankly, if your Perl 5 code is using this, it's almost certainly really, really old.

Closing ticket.