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Re^3: regexp list return 5.6 vs 5.8

by hipowls (Curate)
on Jan 24, 2008 at 09:34 UTC ( #663969=note: print w/replies, xml ) Need Help??


in reply to Re^2: regexp list return 5.6 vs 5.8
in thread regexp list return 5.6 vs 5.8

Really, I too was surprised. Changing sub test to

sub test { my @rv = $_[0] =~ /^([0-9]+)$/; print "<<@rv>>\n"; return @rv[ 0 .. $#rv ]; }
produced
<<>> [[] <<>> [] <<123>> [123] <<123>> [123]
changing sub test to
sub test { my @rv = $_[0] =~ /^([0-9]+)$/; print "<<@rv>>\n"; return wantarray? @rv: $rv[-1]; }
produces
michael$ perl t.pl <<>> Use of uninitialized value in print at t.pl line 5. [] <<>> [] <<123>> [123] <<123>> [123]
Note the warning. (And I suspect there are some monks who are now saying I told you so;-)

Replies are listed 'Best First'.
Re^4: regexp list return 5.6 vs 5.8
by Sixtease (Friar) on Jan 24, 2008 at 09:50 UTC

    Wow, so the [[] was not a typo? I thought it was. I still don't understand how it could have got there! What does it print when you use different delimiters? (like print "{", scalar(test('abc')), "}";)

    use strict; use warnings; print "Just Another Perl Hacker\n";

      Strange indeed.

      michael$ perl t.pl {{} {} {123} {123}

        Putting the call inside a @{[ ... ]} construct does something different.

        print "[@{ [ scalar test('abc') ] }]\n"; print "[", scalar test('abc'), "]\n\n"; print "[@{ [ test('abc') ] }]\n"; print "[", test('abc'), "]\n\n"; print "[@{ [ scalar test('123') ] }]\n"; print "[", scalar test('123'), "]\n\n"; print "[@{ [ test('123') ] }]\n"; print "[", test('123'), "]\n"; sub test { my @rv = $_[0] =~ /^([0-9]+)$/; return @rv[ 0 .. $#rv ]; }

        produces

        [ ] [[] [] [] [123] [123] [123] [123]

        Running 5.8.4 on Solaris 9.

        Cheers,

        JohnGG

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