in reply to Re^3: Switch.pm Failure ( CGI::Switch? )
in thread Switch.pm Failure

"Did you upgrade Perl"

probably, Further, Switch was removed from the core in Perl 5.14 http://stackoverflow.com/questions/2630547/why-is-the-switch-module-deprecated-in-perl

so first they got the message Can't locate Switch.pm in @INC (you may need to install the Switch module), Searched the tree and found a Switch.Pm under CGI, and added use CGI::Switch;, which didnt help a bit.

ok, so since Switch.pm is no longer core, and i didnt want to install it (being depreciated anyway), i took this http://cpansearch.perl.org/src/RGARCIA/Switch-2.16/Switch.pm and put it in its own directory, and then put this into the same directory 

#!perl -w
use strict;use warnings; 
use Switch; 
sub Main { 
Switch {print "hi\n";return;}
}

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and glory be got 
hi

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Why, i dunno?

ok it wasnt that simple. first i tried 

#!perl -w
use strict;use warnings; 
use Switch; 
Switch {my $a=1};

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and got 
Can't locate object method "Switch" via package "1" (perhaps you forgo
+t to load "1"?) at switch.pl line 4.

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Thinking that all those returns were the reason i went to 
#!perl -w
use strict;use warnings; 
use Switch; 
Switch {my $a=1;return};

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and got 
Can't return outside a subroutine at switch.pl line 4.

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AHAH, the reason for the sub Main {}

so i cant figure out what Switch {} is doing. there is no sub Switch in Switch.pm (there is a sub switch tho). I figure it has something to do with use Filter::Util::Call and the import and filter subroutines. Can anyone give me a clue?

edit:fixed case in "Can't locate switch.pm" from a typo/wrong-copy-paste

edit2: ok i think i got it if a class is used to invoke the method, that argument will be the name of the class.http://docstore.mik.ua/orelly/perl/prog3/ch12_03.htm. so Switch {} is trying to invoke method Switch with an argument (without parens) that is the result of a block, but the block "never ends?" due to the return. Is that it?

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Re^5: Switch.pm Failure ( CGI::Switch? )
by haukex (Archbishop) on Feb 27, 2017 at 08:12 UTC
    so Switch {} is trying to invoke method Switch with an argument (without parens) that is the result of a block, but the block "never ends?" due to the return. Is that it?

    Interesting theory, and I did forget about Indirect Object Syntax. It's easy to test, but as it turns out it's unlikely this is what's going on here, due to the returns used everywhere in that code. We still need more information from OP.

    sub Foo::new { bless {}, shift }
sub Foo::Switch { print "Switch @_\n" }

Main();
sub Main {
    Switch { "Foo" };
    Switch { new Foo };
    Switch { return }; # just returns
}
Switch {  }; # this dies

__END__

Switch Foo
Switch Foo=HASH(0x24a5338)
Can't call method "Switch" without a package or object reference at ..
+.

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      The proof is at Re^31: global var. It all started with use Switch;, and the subroutine/returns were to get around the initial invalid use of the Switch method.

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Re^5: Switch.pm Failure ( CGI::Switch? )
by tultalk (Monk) on Feb 26, 2017 at 01:37 UTC
    Ok. Thyanks. But what it the meaning of this: ", but the block "never ends?" due to the return. Is that it?" Best regards
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      The return(s) in the block force the Main subroutine to terminate early, so control is never passed back to the Switch method. Just erase the Switch word, and delete use CGI::Switch; as i suggested before and all will be fine

      The question was very complicated, and by not telling us what was changed you just made it more complicated. If you had told us you were on a newer version of perl and you changed use Switch; to use CGI::Switch; it probably would have been much easier to figure out.

      And whomever "used a hammer to drive that screw in" to make Switch {...} work rather than determine the original problem did you no favors either. Im known to make furniture with a chainsaw and i dont think ive ever done anything that funky.

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