comment on

I realize 5.10's switch statement is quite different from C/etc.'s. But, I've been doing most of my programming lately in Java (uggh) and C# (double uggh). So, I accidentally used 'continue' instead of 'next' in some Perl code, and man, it took a while for me to see what was going on. The short of it is that using 'continue' in a subroutine can affect a given/when that surrounds it. The following demonstrates a (much-simplified) version, with my level of surprise appropriately expressed. Just a reminder to everyone: 'continue' has nothing to do with 'continue' blocks.

#!/usr/bin/perl
use strict;
use warnings;
use feature ':5.10';

sub no_saving_continue {
    for (shift) {
        say "  continue[$_]" and continue if /a/;
        say "  loop[$_]";
    }
}

sub has_saving_continue {
    for (shift) {
        say "  continue[$_]" and continue if /a/;
    } continue {
        say "  loop[$_] (in continue)";
    }
}

for (
    [ 0, no_save => \&no_saving_continue ],
    [ 1, protect => \&has_saving_continue ],
    ) {
    my ($save, $label, $func) = @$_;
    for (qw{a b}) {
        say "\n==== forloop[$_] ($label) ====";
        given ($_) {
            when (['a','b']) {
                say " {explicit $_";
                $func->($_);
                say " explicit $_}";
            } default {
                say " {default $_}", map " SURPRISE", grep $_, $save, 
+/a/;
            }
        }
    }
}
__END__
Output:

==== forloop[a] (no_save) ====
 {explicit a
  continue[a]
 {default a} SURPRISE

==== forloop[b] (no_save) ====
 {explicit b
  loop[b]
 explicit b}

==== forloop[a] (protect) ====
 {explicit a
  continue[a]
 {default a} SURPRISE SURPRISE

==== forloop[b] (protect) ====
 {explicit b
  loop[b] (in continue)
 explicit b}
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In reply to Unexpected behavior of continue in 5.10 by benizi

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