in reply to Re^2: Moose and default values
in thread Moose and default values

Probably you can use it outside Moose, too.
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Re^4: Moose and default values
by tobyink (Canon) on Feb 20, 2013 at 22:39 UTC

    Indeed; it has no ties to Moose. It's simply a function that takes a list and returns a (possibly smaller) list. While it's handy to use it with Moose/Mouse/Moo constructors, it can be used with any functions that take a list of key-value pairs that you want to filter out undefs from.

    package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name
[reply]
      It's nice (and only 10 lines of code :-=).

      But say I now wanted not only undefs but everything that is false (e.g. also an empty string) to trigger the default?

      Does Moose not have any mechanics for that?

[reply]

        Maybe something along the lines of:

        around BUILDARGS => sub {
  my $orig   = shift;
  my $self   = shift;
  my $params = $self->$orig(@_);
  $params->{$_} || delete $params->{$_}
    for qw/ foo bar /;
  return $params;
};

        [download]

        This will discard false parameters for the "foo" and "bar" attributes.

        package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name
[reply]
[d/l]

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