Access hash key of module whose module is not know till runtime

Question

So I figured out how to load a module whose $module_name is not known till runtime.

Now, I wish to access a hash key, whose value happens to be a CODEREF.

my $hash_key = 'SOME_KEY';
my $code_ref = ${$module_name::hash}{$hash_key};

Then say:

$code_ref->(@args);

The ${$module_name::hash}{$hash_key} is odd to me and I wonder if it works as intended?

score 3 · Accepted Answer · answered Dec 22 '15 at 22:15

Sort of. What you wrote won't work ($module_name::hash is the scalar variable $hash in the package module_name), but this will:

my $code_ref = ${$module_name . "::hash"}{$hash_key};

This kind of construction is ... discouraged, and prohibited under use strict 'refs'. I don't know what your use case is, but another approach to consider is to implement some common methods in your dynamically loaded modules.

my $code_ref = $module_name->getCode($hash_key);
$code_ref->(@args);

ikegami · Answer 2 · 2015-12-23T01:09:39.703

2

${ $module_name . "::hash" }{$hash_key}

or

( $module_name . "::hash" )->{$hash_key}

Of course, you'll have to use no strict qw( refs ); in the scope in which you do that.

my $hash = do { no strict qw( refs ); \%{ $module_name . "::hash" } };
$hash->{$hash_key}

edited Dec 23 '15 at 01:09

answered Dec 22 '15 at 22:52

ikegami

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Wtf? They were different. Fixed – ikegami Dec 23 '15 at 01:09
could/would `eval` help us in the TIMTOWTDI spirit? – lzc Dec 23 '15 at 14:06
1

That would be very heavy, and could require validation. It's not the approach I'd recommend, nor the one usually used. – ikegami Dec 23 '15 at 18:47

Access hash key of module whose module is not know till runtime

2 Answers2