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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)

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

> 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 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
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.

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