use strict; use warnings; my (%Foo, %Bar); sub foo : lvalue { $Foo{+shift} }; sub bar { my $key = shift; $Bar{$key} = shift if @_; $Bar{$key}; }; foo("apples") = 12; foo("pears") = 0; print foo("apples"), "\n"; print foo("pears"), "\n"; bar(bananas => 3); bar(oranges => 18); print bar("bananas"), "\n"; print bar("oranges"), "\n"; #### sub bar { my $key = shift; if (@_) { die "no negative numbers" if $_[0] < 0; $Bar{$key} = shift; }; $Bar{$key}; };