Perl Hash of Subfunctions

Question

I wish to have a hash containing references to sub-functions where I can call those functions dependent upon a user defined variable, I will try and give a simplified example of what I'm trying to do.

my %colors = (
    vim => setup_vim(),
    emacs => setup_emacs(),
)

$colors{$editor}(arg1, arg2, arg3)

where setup_vim() and setup_emacs() would be sub-functions defined later in my file and $editor is a user defined variable (ie vim or emacs). Is this possible? I can't get it working, or find good information on the subject. Thanks.

(Note I have it implemented right now as a working Switch, but I think a hash like the above would make it easier to add new entries to my existing code)

Answer 1

Here is the syntax.

my %colors = (
    vim => \&setup_vim,
    emacs => \&setup_emacs,
);

$colors{$editor}(@args)

Note that you can actually create functions directly with

my %colors = (
    vim => sub {...},
    emacs => sub {...},
);

And if you're familiar with closures, Perl supports full closures for variables that have been declared lexically, which you can do with my.

Answer 2

You have to pass a reference to the subroutine you want to call into the hash.

Here's an example:

sub myFunc {
   print join(' - ', @_);
}

my %hash = ( key => \&myFunc );
$hash{key}->(1,2,3);

With \&myFunc you get the reference wich points at the function. Important is to leave the () away. Ohterwise you would pass through a reference to the return value of the function.

When calling the function by reference you have to derefence it with the -> operator.