gistfile1.pl

#!/usr/bin/perl

use warnings;
use strict;
use 5.010;

# State variable is declared inside the loop, instantiated once, and counts correctly.
# Prints clicker values of 1, 2, 3, 4, 5
for my $i ( 1..5 ) {
    state $foo_clicker;
    ++$foo_clicker;
    say "foo's clicker = $foo_clicker";
}


# State is in an anonymous sub, but only instantiated once, and counts correctly.
# Prints clicker values of 1, 2, 3, 4, 5
my $bar_sub = sub {
    state $bar_clicker;
    ++$bar_clicker;
    say "bar's clicker = $bar_clicker";
};
for my $i ( 1..5 ) {
    $bar_sub->();
}


# State is in an anonymous sub that is compiled five times, so
# instantiated five times, and counts wrong.  This is how subtest()s are done.
# Prints clicker values of 1, 1, 1, 1, 1 because it is reset every time.
for my $i ( 1..5 ) {
    my $baz_sub = sub {
        state $baz_clicker;
        ++$baz_clicker;
        say "baz's clicker = $baz_clicker";
    };
    $baz_sub->();
}