Re: foreach $1

Interesting, thanks for showing! ++

Can anyone guess of a special var other than $_ where aliasing might make sense?

Otherwise shouldn't we make a feature request to throw a compilation error?

(At least under strict or warnings?)

edit

Hmm ...

Should be noted here that a special var makes the whole typeglob special.

I.e. if $a is a special var then @a and %a will act special too, even without carrying a meaning.

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

Comment on Re: foreach $1

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Re^2: foreach $1 by kcott (Archbishop) on Jun 06, 2020 at 17:50 UTC
G'day Rolf, "Can anyone guess of a special var other than $_ where aliasing might make sense?" I made a quick scan through perlvar and nothing leapt out at me as being appropriate for this. "Otherwise shouldn't we make a feature request to throw a compilation error? (At least under strict or warnings?)" I'm not sold on making it a fatal error but I do think a warning may be appropriate. I had a look at "warnings: Category Hierarchy" but didn't think any existing category was really suitable: maybe create a new top-level category or a new sub-category of "syntax". — Ken	[reply]
Re^3: foreach $1 by LanX (Saint) on Jun 06, 2020 at 21:52 UTC
Well I'm not sure yet. I've tested with $a and the loop var didn't interfere with the sort block. Probably we need to decide case by case... Though my gut feeling says all non alphabetic symbols should cause a warning when used as a loop alias. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply]
Re^4: foreach $1 by choroba (Cardinal) on Jun 06, 2020 at 23:47 UTC
Yes, $a and $b seem to be OK. $" also seems to work, but $\ doesn't: `for $\ (qw( a b c d )) { print "@{[1, 2, 3]}"; } # Output: # 1 2 31 2 31 2 31 2 3` [download] `map{substr$_->[0],$_->[1]\|\|0,1}[\\|\|{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^ARGV,3]`	[reply] [d/l] [select]
Re^5: foreach $1 -- all special variables by Discipulus (Canon) on Jun 07, 2020 at 19:36 UTC
Re^6: foreach $1 -- all special variables by LanX (Saint) on Jun 07, 2020 at 19:43 UTC
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Re^5: foreach $1 by LanX (Saint) on Jun 07, 2020 at 02:19 UTC
Re^6: foreach $1 by ikegami (Patriarch) on Jun 08, 2020 at 22:12 UTC
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Re^2: foreach $1 by ikegami (Patriarch) on Jun 08, 2020 at 22:25 UTC
if $a is a special var then @a and %a will act special too, even without carrying a meaning. Well, they are considered "declared", but that's the extent of it.	[reply]
Re^3: foreach $1 by LanX (Saint) on Jun 08, 2020 at 23:55 UTC
> I.e. if $a is a special var then @a and %a will act special too, even without carrying a meaning. > > Well, they are considered "declared", but that's the extent of it. Nope, e.g. $% is a special var which is global, @% isn't documented anywhere, but still global `DB<1> x @%=1..3 0 1 1 2 2 3 DB<2> x {package A; @%} 0 1 1 2 2 3 DB<3> x @a=1..3 # not global 0 1 1 2 2 3 DB<4> x {package A; @a} empty array DB<5>` [download] Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l]