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Re: [Chicken-users] New immediate values (was: DBI)
From: |
John Cowan |
Subject: |
Re: [Chicken-users] New immediate values (was: DBI) |
Date: |
Fri, 29 Feb 2008 21:40:40 -0500 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Thomas Chust scripsit:
> for example in Java there are some places where the dynamic type of null is
> effectively a subtype of another class:
>
> // this returns (String)null and doesn't throw a ClassCastException
> "foo".getClass().cast(null)
c
Yes, well, that is where static typing is done at runtime.
> So the static typing behaviour may differ from the dynamic one and it may
> be inconsistent. But a distinction between static and dynamic typing
> behaviour wouldn't apply to Scheme.
True, and what I'm saying is that the dynamic behavior is the appropriate
one.
> Of course I don't want to have the same typing mess as in Java in CHICKEN
> and I do think the whole practice of having nullable reference types (by
> default) is questionable. I just don't think it is completely canonical
> that the type of NULL should be disjoint from every other type, especially
> if you think of types as being sets (or classes) of objects.
I do think of types as being named sets of objects (named, because then there
are only denumerably many types).
> If Foo.bar is a static method this will work just fine ;-)
Yup. But did you deduce that from first principles, or had you seen
it before?
--
John Cowan address@hidden http://ccil.org/~cowan
The penguin geeks is happy / As under the waves they lark
The closed-source geeks ain't happy / They sad cause they in the dark
But geeks in the dark is lucky / They in for a worser treat
One day when the Borg go belly-up / Guess who wind up on the street.