in reply to Subroutine references inside of a hash with arguments.

With

"1" => \&get_ifc_name,

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the hash value is a reference to the subroutine get_ifc_name, but with

"1" => \&get_ifc_name({'ifc_default' => 'test_me',}),

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the hash value is a reference to whatever that subroutine returns when called with the specified argument. Even if the subroutine returns a reference to a subroutine, it will be inconsistent with the previous case.

Maybe, instead of a single value for each element of the %menu_hash hash, you should have a reference to a hash, something like:

"1" => { sub => \&get_ifc_name, args => {'ifc_default' => 'test_me',} 
+},

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Later, you can call this with

$menu_hash{1}{sub}->($menu_hash{1}{args});

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Re^2: Subroutine references inside of a hash with arguments.
by ikegami (Patriarch) on Jul 25, 2009 at 04:56 UTC
    What's the advantage of that over what I posted?
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      It is a little easier to modify the arguments independently of the subroutine to be called, at the cost of a more complex data structure and more complex subroutine calls.

      One way this could be done, as the subroutine is called, is as follows:

      $menu_hash{1}{sub}->({
    %{$menu_hash{1}{args}},      # default arguments/values
    ifc_default => 'overridden', # override default value
    ifc_color => 'green',        # add an argument/value
});

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      There would be no point including the arguments hash from $menu_hash if, as in this case, it included only one element which was being overridden, but it could have other elements, only some of which are overridden in a given call.

      The arguments could be set or changed independently of either setting or calling the subroutine to be called.

      Whether these are advantages or not will depend on the situation. The name 'ifc_default' suggests that there might be situations where non-default arguments might be passed.

      But I think I like the method LanX suggested better than my own, now that I think about it.

      update: and then I realized that what your suggested is very similar to what LanX suggested, and additional/override arguments can easily be included in your approach.

      "1" => sub { get_ifc_name({'ifc_default' => 'test_me', %{shift} }) },

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      after which

      $menu_hash{1}->({ifc_default => 'overridden', color => 'green'});

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      So, after all, I like my own suggestion least of all. Thanks for questioning it.

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        and additional/override arguments can easily be included in your approach.

        "1" => sub { get_ifc_name({'ifc_default' => 'test_me', %{shift} }) },

        don't you think that an explicit currying function like setdefaults(), is clearer, better maintainable, more DRY and scalable?

        I supposed there are more than just one coderef to be parameterized.

        And even if there is just one, IMHO the above "literal" code is not immediately understood by many coders... changed my mind it's not so obscure, if you only need one currying at all it might be better this way. :-)

        Cheers Rolf

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