lib/MooseX/UndefTolerant/Constructor.pm

   1 package MooseX::UndefTolerant::Constructor;
   2 use Moose::Role;
   3
   4 if ( $Moose::VERSION < 1.9900 ) {
   5         around('_generate_slot_initializer', sub {
   6                 my $orig = shift;
   7                 my $self = shift;
   8
   9                 # note the key in the params may not match the attr name.
  10                 my $key_name = $self->_attributes->[$_[0]]->init_arg;
  11
  12                 # insert a line of code at the start of the initializer,
  13                 # clearing the param if it's undefined.
  14
  15                 if (defined $key_name)
  16                 {
  17                     # leave the value unscathed if the attribute's type constraint can
  18                     # handle undef (or doesn't have one, which implicitly means it can)
  19                     my $type_constraint = $self->_attributes->[$_[0]]->type_constraint;
  20                     if ($type_constraint and not $type_constraint->check(undef))
  21                     {
  22                         my $tolerant_code =
  23                              qq# delete \$params->{'$key_name'} unless # .
  24                              qq# exists \$params->{'$key_name'} && defined \$params->{'$key_name'};\n#;
  25
  26                         return $tolerant_code . $self->$orig(@_);
  27                     }
  28                 }
  29
  30                 return $self->$orig(@_);
  31 });
  32
  33 no Moose::Role;
  34
  35 1;