Your Welcome! :)

But I suppose you don't want the sub missing() to be available as method the way ->foo() is?

And while the MISSING object is a nice workaround for the semi-predicate problem, I still think it's an overkill here.

Like I said you could just slurp into @val and have the full functionality, with less code:

use strict;
use warnings;
use experimental "signatures";
use Carp;

{
    package BLA;

    sub new ($class,@properties) {
        return bless {@properties}, $class;
    }


    sub foo ($self, @val) {
        unless (@val){                  # getter
            return $self->{foo}
        } elsif (@val == 1) {           # setter
            return $self->{foo} = $val[0];
        } else {                        # ERROR
            local $" = ",";
            Carp::croak "Too many arguments for method 'BLA->foo(@val)
+'";
        }
    }
}




my $x = BLA->new(foo=>42);

warn "getter:", $x->foo;
warn "setter:", $x->foo(666);
warn "getter:", $x->foo;
warn "error:",  $x->foo(42,666);
[download]

-*- mode: compilation; default-directory: "d:/tmp/pm/" -*-
Compilation started at Fri Jan  8 21:39:32

C:/Perl_524/bin\perl.exe -w d:/tmp/pm/missing_param.pl 
getter:42 at d:/tmp/pm/missing_param.pl line 31.
setter:666 at d:/tmp/pm/missing_param.pl line 32.
getter:666 at d:/tmp/pm/missing_param.pl line 33.
Too many arguments for method 'BLA->foo(42,666)' at d:/tmp/pm/missing_
+param.pl line 34.

Compilation exited abnormally with code 255 at Fri Jan  8 21:39:33
[download]

updates

improved code with croak and better error message

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.