in reply to Re: Default subroutine parameters (boo)
in thread Default subroutine parameters

sub foo {
  my %defaults = ( qw( foo 9 bar 8 baz 7 ) );
  my %args = ( %defaults, @_ );

  ...
}

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Re: Re: Re: Default subroutine parameters (boo)
by thelenm (Vicar) on Apr 23, 2002 at 16:21 UTC
    I really like this solution because it's syntactically simple. It works when an argument is omitted entirely, but unfortunately it doesn't supply the default value when the value 'undef' is passed as an argument, like this: 
    mysub(foo => 0, bar => 1, baz => undef);

sub mysub {
  my %defaults = qw(foo 9 bar 8 baz 7);
  my %args = (%defaults, @_);
  print "Foo: $args{foo}, Bar: $args{bar}, Baz: $args{baz}\n";
}

    [download]

    But it's inspired me to see if I can modify it to suit my needs. Thank you!

[reply]
[d/l]

      It doesn't supply a default because you've supplied a value (undef). If you want the default, don't supply something with that key as a parameter. You're presuming an idiom `replace undef parameters with the default value' where this code implements `replace unspecified parameters with the default value'.

[reply]
[d/l]

        You're presuming an idiom `replace undef parameters with the default value'

        Right, that was the question I asked. :-)

[reply]

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