in reply to Simple Query on Operators

What exactly are you trying to do in the initialization of $foo? I've always (unthinkly) used the ternary form.

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Re^2: Simple Query on Operators
by Ewok_Wrangler (Initiate) on Mar 04, 2008 at 16:07 UTC
    What prompted this was throwing @_ to a hash, like:

    my ($self, %args) = @_;

    And wanting to allow variables to be optional. The little snippet I posted basically sets a variable to a default if it isn't given in the arguments.

    Again, this is a pointless question in that I don't need to answer it. I'm just curious and always try to figure out how a language "thinks" when I pick it up.
[reply]
      It's far from pointless. A great way of setting a default is: $foo ||= $hash{key};

      That is, if the variable $foo does not already have a value, give it the value of $hash{key}.

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      Another way to do this is with a separate %DEFAULTS hash that gets mixed in with the arguments passed. 

      use Data::Dumper;

my %DEFAULTS = ( a => 'a default',
                 b => 'b default',
                 c => 'c default', );
my %args = ( a => 'a arg',
             b => undef, );
%args = ( %DEFAULTS, %args );

print Dumper \%args;
__END__
$VAR1 = {
          'c' => 'c default',
          'a' => 'a arg',
          'b' => undef
        };

      [download]

      Notice that this method keeps a value that exists but is not defined, so somebody can explicitly pass in undef if they want to. This may or may not be what you want.

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