#!perl
use strict;
use warnings;

sub lambda {
  my $varname = shift;
  my $fn = shift;
  my $pkg = do { no strict 'refs'; * {caller().'::'} };
  sub {
    local ${$pkg}{$varname} = \shift;
    $fn->()
  }
}

package a::b::c;

our $x;
my $closure = main::lambda 'x' => sub { $x**2 };
for (1..4) {
  print $closure->($_), "\n";
}