You're right in that C# and Java have a lot of duplication in this case. It'd certainly be nice to have to type what I mean only once. Here's some food for thought, though.

A good type-inferring system can gather, at compile time, the type of $dog in this construct:

my $dog = Dog->new();

I'll probably write much, much more code that actually works with a Dog than code that instantiates a Dog. It seems more valuable to have the option to strictify your type checking these situations, where type inference really can't help: 

method bark_at (Dog $some_other_dog, $message)
{
    # horrible Perl6y pseudo-code
    print "$.name says to $some_other_dog.name, '$message'\n";
};

[download]

I wouldn't expect bark() to autoinstantiate a Dog object, but effectively it's declaring a lexical $some_other_dog that somehow conforms to Dog.

It'd also be weird to say: 

class DogShow
{
    my Dog @showdogs;
}

[download]

and fill an array with placeholder Dogs. I might want to throw a robot dog in there, or a Puppy, or something that's not specifically a Dog.

In reply to Re: Fun with Typed Objects 1 by chromatic
in thread Fun with Typed Objects 1 by John M. Dlugosz

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