Binding values to functions in Perl

Answer 1

without posting more example code its hard to give a complete answer, but when you call your sub from the hash, why not pass it the lock value?

my $num = ... # get lock number;

$users_menu{"n"}[1]->($num)

# calls "new_user" passing it $num

question edited:

sub menu_prompt {
    my $options = shift;

    print_options $options;

    my $choice = <>; # i assume the diamond operator got stripped
    chomp $choice;   # second my is in error

    if (defined $$options{$choice}) {
        return $$options{$choice}[1](@_); 
             # any additional arguments to menu_prompt will be passed to the sub
             # return the value for future processing
    }
}

Answer 2

I have to say I don't completely understand your question, but anonymous subroutines might help you

my $id = (somehow get the ID);

my %users_menu = (
    "l" => ["list users", sub {list_users($id)}], 
                   #now, the id is fixed and the subroutine can be called without arguments
    "n" => ["new user", \&new_user]);

Answer 3

You are wanting to curry functions.

There are many CPAN modules (see end of post) for currying. Here's an example of curry by closure.

sub curry {
    my $f = shift;
    my $a = shift;
    sub { $f->( $a, @_ ); }
}


my ($input, $func);
$input = 2;
$func  = curry( sub { print join "\n", @_ }, $input );

$input = 12;
$func  = curry( $func , $input );

$input = 99;

$func->(4,6,8,10,19);


#outputs
2
12
4
6
8
10
19

Also see Data::Util, Sub::Curried, and Sub::Curry.

HTH