enigma has asked for the wisdom of the Perl Monks concerning the following question:

Hello PerlMonks,

I need your help to understand how to use a hash value as a subroutine name while "strict ref" is in use-

use strict;

my $code_ref = {'SUM', 'sum'};
sub sum($$){...}

($codes->{'SUM'})->(4,5);

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Result: gives an error -

Can't use string ("sum") as a subroutine ref while "strict refs" in use at ...

Thanks.

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Re: HASH value as a subroutine call
by Perlbotics (Archbishop) on Oct 21, 2012 at 10:49 UTC

    You need to populate the hash with code-references (\&sub).

    Try: 

    use strict;

# my $code_ref = {'SUM', 'sum'};  
  my $code_ref = {'SUM', \&sum};

sub sum($$){...}   # do you really need ($$) ? That is rarely useful. 

# ($codes->{'SUM'})->(4,5);   # $codes? You mean $code_ref?
$code_ref->{'SUM'}->(4,5);

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      sub sum($$){...}   # do you really need ($$) ? That is rarely useful.

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      Rarely useful, often misused, and in this case (in which prototypes are not checked at all) totally useless. E.g.: 

      >perl -wMstrict -le
"sub sum ($$);
 ;;
 my $codes = { 'SOFT' => 'sum',  'HARD' => \&sum, };
 ;;
 $codes->{HARD}->('HARD', 1, 2, 3, 4);
 ;;
 {
 no strict 'refs';
 $codes->{SOFT}->('SOFT', 9, 8, 7, 6);
 }
 ;;
 sub sum ($$) { print qq{(@_)  arguments: }, scalar @_; }
"
(HARD 1 2 3 4)  arguments: 5
(SOFT 9 8 7 6)  arguments: 5

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Re: HASH value as a subroutine call
by Anonymous Monk on Oct 21, 2012 at 10:49 UTC
[reply]

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