http://www.perlmonks.org?node_id=11132260


in reply to Attempting to use $_ in "sub" inside "map"

One way, albeit not pretty, is to form a closure | lexical closure (if that's the proper terminology) over the value of the global $_ and use the closed-over value:

Win8 Strawberry 5.8.9.5 (32) Sat 05/08/2021 0:53:55 C:\@Work\Perl\monks >perl use strict; use warnings; my %dispatch = ( normal => sub{"$_[0] Normal dispatch"}, map { my $__ = $_; $_ => sub{"$_[0] Sub returns $__"} } qw| Uno Dos tres| ); print $dispatch{"normal"}->(0),"\n"; # 0 Normal dispatch (as expected +) print $dispatch{"Uno"} ->(1),"\n"; # WANT: "1 Sub returns Uno" print $dispatch{"Dos"} ->(2),"\n"; # WANT: "2 Sub returns Dos" ^Z 0 Normal dispatch 1 Sub returns Uno 2 Sub returns Dos

Update 1: Also see this article on closure.

Update 2: Another way, not involving closures - although closures are not to be scorned!

Win8 Strawberry 5.8.9.5 (32) Mon 05/10/2021 9:33:38 C:\@Work\Perl\monks >perl use strict; use warnings; my %dispatch = ( normal => sub{ "$_[0] Normal dispatch" }, map { $_ => eval qq{ sub{ "$_ returns \$_[0]" } } } qw(Uno Dos tre +s), ); print $dispatch{'normal'}->( 0), "\n"; print $dispatch{'Uno' }->( 1), "\n"; print $dispatch{'Dos' }->( 22), "\n"; print $dispatch{'tres' }->(333), "\n"; ^Z 0 Normal dispatch Uno returns 1 Dos returns 22 tres returns 333


Give a man a fish:  <%-{-{-{-<