my %hash = map { my $item = pop @$_; map { $_, $item } @$_ }
  [qw(HELP ?) => sub { ... }],
  [qw(QUIT EXIT LEAVE) => sub { ... }],
  ...;
[download]

-- Randal L. Schwartz, Perl hacker

Thank you, Randal. That looks about right, and perfectly Perlish.

$_="goto+F.print+chop;\n=yhpaj";F1:eval

I know I'm only 3 years late, but could someone explain/dissect in teaching terms, just what merlyn did. /msg me if you wouldn't mind so I know it's up. Thanks.

—Brad
"A little yeast leavens the whole dough."

It'd help if you explained what parts you already do understand, so we don't have to repeat that. Do you know what qw() does? How about map? References? sub{}?

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

#!/usr/local/bin/perl -w

use strict;

my %hash = ('HELP' => \&do_help,
            '?'    => 'HELP',
            'LIST' => \&do_list,
            'SHOW' => 'LIST',
            'TEST' => \&do_test,
           );
           
{
   while (my ($k, $v) = each (%hash))
   {
      $hash {$k} = $hash {$v} if (ref $hash {$k} ne 'CODE');
   }

   &{$hash {'HELP'}};
   &{$hash {'?'}};
   &{$hash {'LIST'}};
   &{$hash {'SHOW'}};
   &{$hash {'TEST'}};
}

sub do_help {print "help\n"}
sub do_list {print "list\n"}
sub do_test {print "test\n"}
[download]

my %h = (
    HELP => $_ = sub {print "help\n"},
    "?"  => $_,
    SAVE => sub {print "save\n"},
);
[download]

my ($help, $save);
my %h = (
    HELP => $help = sub {print "help\n"},
    "?"  => $help,
    SAVE => $save = sub {print "save\n"},
    EXIT => $save,
);
[download]

I'm trying to improve on sandfly's code by eliminating the need for temp variables, but getting into trouble. Why does the following code produce
"Use of uninitialized value in subroutine entry at -e line 1.
Undefined subroutine &main:: called at -e line 1."

my %h=(   HELP => sub {print qq(help\n)},
                  Q=>$h{HELP},
                SAVE=>sub{print qq(save\n)} ); 
print $h{Q}();
[download]

I have also tried it by separating the declaration and population of %h, to no avail.

I suspect it's because $h{HELP} doesn't exist when you create the tuple Q=>$h{HELP}, as %h hasn't been assigned to at that time.

Perhaps this will work for you:

use Data::Dumper;
my %h=(   HELP => sub {print qq(help\n)},

                SAVE=>sub{print qq(save\n)} ); 
$h{Q} = $h{HELP};
print Dumper(%h);
print $h{Q}();
[download]

Result:

$VAR1 = 'Q';
$VAR2 = sub { "DUMMY" };
$VAR3 = 'HELP';
$VAR4 = $VAR2;
$VAR5 = 'SAVE';
$VAR6 = sub { "DUMMY" };
help
1
[download]

Note that HELP and Q both use the same sub.

-QM
--
Quantum Mechanics: The dreams stuff is made of

OK I answered my own question based on one of my old writeups. It IS possible to eliminate the temporary variable by coding as follows:

use strict;
my %h; #Pre-declare so it can be referenced inside populating code
%h=(      HELP => sub {print qq(help\n)},
          '?'=>sub{$h{HELP}()},
          SAVE=>sub{print qq(save\n)},
          EXIT=>sub{$h{SAVE}()}  );
 $h{'?'}();
 $h{EXIT}();
[download]

This prints the lines:
help
save