2.3. Dynamic References to Functions

It is possible to define a dynamic reference to a function. The code of its function is written as part of the assignment expression and can see all the variables in the scope in which it was defined. Here's an example:

#!/usr/bin/perl

my ($increment);

{
    my $counter;
    # The definition of a dynamic reference to function comes inside
    # a "sub {" ... "}" closure
    $increment = sub {
        print $counter, "\n";
        return $counter++;
    };
}

my $a;
while (($a = $increment->()) < 100)
{
    # Do Nothing
}

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