Re: [Sbcl-devel] clos typechecking

[Marco A. <ma...@cs...>]

On Jul 22, 2004, at 1:20 PM, Alexey Dejneka wrote:

> Marco Antoniotti <ma...@cs...> writes:
>>
>> As I said, I am more interested in "simple" typechecking rather that
>> "typechecking aimed at optimization".  Of course, the second one is a
>> very good thing indeed.
>>
>> As another interesting problem, think of the following
>>
>> (defclass foo () ((bar :accessor bar :type vector)))
>>
>> (defclass zot () ((bar :type string)))
>>
>> (defclass zut (foo zot) ())
>>
>> What should the FTYPE of BAR be at this point?
>
> (FUNCTION * *). But the compiler may also know, that if BAR's argument
> is of type ZUT, then the result will be (AND VECTOR STRING) [as long
> as the definition of FOO/ZOT/ZUT is the same FSVO "as long"].


Yep.  Exaclty my point.  Can we write a compiler that does that?

Cheers

--
Marco Antoniotti					http://bioinformatics.nyu.edu
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