No strict refs

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

Is there anyway to refactor this so that it does not need the no strict 'refs', and can work under Modern::Perl without it?

use Modern::Perl;$_='
<use><qd>action</></>
<use><qd>action</></>
';

$_{'s'} = { jeopardy =>"21"};
$_{'qd'} = { action => 'default' };

sub dbl { say "this should only calc once";
          $_{'dbl'}->{$_[0]} = $_[0]*2; }

sub use { $_{'use'}->{$_[0]} = &simulate_opening_file; }

sub simulate_opening_file
   { say "this should only slurp once";
    "The answer is <dbl><s>jeopardy</></>" };

while (/<([^<]+?)>([^<]*?)<\/>/)
     {
      my $l=$+[0]-$-[0];
      no strict 'refs';
      my $r = $_{$1}->{$2} ||= $1->($2);
      substr($_,$-[0],$l,$r);
     }

say;
[download]

Comment on No strict refs Select or Download Code

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Re: No strict refs by ikegami (Patriarch) on Aug 21, 2011 at 04:13 UTC
`use strict 'refs';` is what's preventing `simulate_opening_file` from being called if someone did `<simulate_opening_file>...</>`, so I applaud your desire to use it. Two options: Keep using `no strict 'refs';`, but require that the callbacks are located in a specific patckage that contains nothing but callbacks. `1 while s/<([^<]+?)>([^<]?)<\/>/ $_{$1}->{$2} \|\|= do { #TODO: Make sure $1 doesn't contains "::". my $func = $pkg . "::" . $1; #TODO: Make sure $func exists. no strict 'refs'; $func->($2) } /e;` [download] Require that callbacks get registered. `my %cb = ( use => \&use, dbl => \&dbl, ); 1 while s/<([^<]+?)>([^<]?)<\/>/ #TODO: Make sure $cb->{$1} exists. $_{$1}->{$2} \|\|= $cb->{$1}->($2) /e;` [download] By the way, you'll have problems if the replacement value contains a "`<`".	[reply] [d/l] [select]
Re: No strict refs by Anonymous Monk on Aug 21, 2011 at 03:22 UTC
First I would refactor it to use meaningful variable names	[reply]
Re: No strict refs by JavaFan (Canon) on Aug 21, 2011 at 23:57 UTC
Use `goto`: `use 5.010; use strict; use warnings; sub foo { say "This is foo <@_>" } sub bar { say "This is bar <@_>" } sub call { my $sub = shift; goto &$sub; } $_ = "foo 123 foo bar bar 456"; while (/(\w+) (\w+)/g) { call $1, $2; } __END__ This is foo <123> This is foo <bar> This is bar <456>` [download] Of course, that only helps to circumvent the `no strict 'refs';`. It doesn't solve anything that `no strict 'refs';` tries to protect you from. Adapting the trick so it works with your templating system is left as an exercise to the reader.	[reply] [d/l] [select]