Re: Case where '( shift @_ )[ 0, 0 ]' returns only one value?

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Re^2: Case where '( shift @_ )[ 0, 0 ]' returns only one value? by Paladin (Vicar) on Jan 14, 2019 at 21:47 UTC
Looks like some kind of change somewhere between 5.18.4 and 5.20.3: `[~]$ perlbrew exec perl -le '@_ = qw( a b c ); @A = ( shift @_ )[ 0, 0 + ]; print @A' [...] perl-5.22.2 ========== aa perl-5.20.3 ========== aa perl-5.18.4 ========== a perl-5.16.3 ========== a perl-5.14.4 ========== a` [download]	[reply] [d/l]
Re^3: Case where '( shift @_ )[ 0, 0 ]' returns only one value? by stevieb (Canon) on Jan 14, 2019 at 21:52 UTC
I confirm these findings (on Perl running on Windows at least). `> berrybrew exec perl -le "@_ = qw( a b c ); @A = ( shift @_ )[ 0, 0 ] +; print @A" perl-5.28.1_64 ============== aa perl-5.20.3_64 ============== aa perl-5.18.4_64 ============== a` [download]	[reply] [d/l]
Re^4: Case where '( shift @_ )[ 0, 0 ]' returns only one value? by stevieb (Canon) on Jan 14, 2019 at 22:41 UTC
I was going to just edit my post after I got my `perlbrew available` issue sorted (which I did), but this warrants a new post. In 5.10, it produces the result `aa` that is expected by OP: `spek@scelia ~/scratch $ perlbrew exec perl -le '@_ = qw( a b c ); @A = + ( shift @_ )[ 0, 0 ]; print @A' perl-5.27.10 ========== aa perl-5.26.1 ========== aa perl-5.20.0 ========== aa perl-5.18.4 ========== a perl-5.10.1 ========== aa` [download] Going full out, and am installing as many versions as I can to see where it "broke", where it "fixed" and where it "broke" again. Help desired. Update: To further, on Unix, it "works" up to 5.12.5, from my testing so far, then goes awry: `spek@scelia ~/scratch $ perlbrew exec perl -le '@_ = qw( a b c ); @A = + ( shift @_ )[ 0, 0 ]; print @A' perl-5.27.10 ========== aa perl-5.26.1 ========== aa perl-5.20.0 ========== aa perl-5.18.4 ========== a perl-5.16.0 ========== a perl-5.14.4 ========== a perl-5.12.5 ========== aa perl-5.10.1 ========== aa` [download]	[reply] [d/l] [select]
Re^2: Case where '( shift @_ )[ 0, 0 ]' returns only one value? by rsFalse (Chaplain) on Jan 14, 2019 at 21:27 UTC
This is perl 5, version 18, subversion 2 (v5.18.2)	[reply]
Re^3: Case where '( shift @_ )[ 0, 0 ]' returns only one value? by stevieb (Canon) on Jan 14, 2019 at 21:35 UTC
Ok. I'll do some installs of other versions on Linux and Windows and try to get to the version where it's borked while I finish my work day. On my Windows system I sometimes develop on, with 5.28.1, I get the `aa` as well: `c:\repos\berrybrew>perl -le "@_ = qw( a b c ); print( ( shift @_ )[ 0, + 0 ] );" aa c:\repos\berrybrew>perl -le "@_ = qw( a b c ); @A = ( shift @_ )[ 0, 0 + ]; print @A" aa c:\repos\berrybrew>perl -v This is perl 5, version 28, subversion 1 (v5.28.1) built for MSWin32-x +64-multi-thread` [download]	[reply] [d/l] [select]
Re^4: Case where '( shift @_ )[ 0, 0 ]' returns only one value? by AnomalousMonk (Archbishop) on Jan 14, 2019 at 21:41 UTC
This behavior appears somewhere between versions 5.12.3 and 5.14.4, but a quick scan of the deltas (update: between these versions) shows no justification for it. (Update: All code run under Windows 7.) `c:\@Work\Perl\monks>perl -wMstrict -le "print 'perl version: ', $]; ;; use Data::Dumper; ;; @_ = qw( a b c ); print( ( shift @_ )[ 0, 0, 0 ] ); ;; @_ = qw( a b c ); my @A = ( shift @_ )[ 0, 0, 0 ]; print Dumper \@A; ;; @A = ( 'x', 'y', 'z' )[ 0, 0, 0 ]; print Dumper \@A; " perl version: 5.012003 aaa $VAR1 = [ 'a', 'a', 'a' ]; $VAR1 = [ 'x', 'x', 'x' ]; perl version: 5.014004 aaa $VAR1 = [ 'a', undef, undef ]; $VAR1 = [ 'x', 'x', 'x' ];` [download] Version 5.14 is the latest I can access ATM. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^5: Case where '( shift @_ )[ 0, 0 ]' returns only one value? by stevieb (Canon) on Jan 14, 2019 at 21:49 UTC
Re^3: Case where '( shift @_ )[ 0, 0 ]' returns only one value? by markong (Pilgrim) on Jan 14, 2019 at 22:12 UTC
I got the same thing with perl 5, version 18, subversion 1 (v5.18.1) built for x86_64-linux-thread-multi	[reply]