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Re: Sequential defined-or operators

by Util (Priest)
on Jan 14, 2008 at 22:21 UTC ( #662388=note: print w/replies, xml ) Need Help??

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', );

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Re^2: Sequential defined-or operators
by plobsing (Friar) on Jan 15, 2008 at 02:39 UTC
    Thats all fine and good until your default value is ask_user(). Then this fails due to eager evaluation. // fixes this fortunately.
      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';

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