Re: Sequential defined-or operators

[Util]

in reply to Sequential defined-or operators

While you remain pre-5.10, you might like this technique:

use List::Util qw( first );
my $theme = first { defined $_ } (
    $global_config->{modes}{$current_mode}{theme},
    $theme_config->{current_theme},
    $default_theme,
    'none',
);

[plobsing]

Thats all fine and good until your default value is ask_user(). Then this fails due to eager evaluation. // fixes this fortunately.

[ikegami]

It took me a second to understand that you are referring to the short-circuiting nature of //. If you needed the short-circuiting behaviour pre-5.10, here's one solution:

sub first(&@) {
   my $cb = shift(@_);
   for (@_) {
      my $i = ref eq 'CODE' ? $_->() : $$_;
      my $rv;
      $rv = $cb->() for $i;
      return $i if $rv;
   }
   return;
}

my $theme = first { defined }
   \$global_config->{modes}{$current_mode}{theme},
   \$theme_config->{current_theme},
   \&ask_user,
   \'none';