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Re: meta-comment on typing



Marcin 'Qrczak' Kowalczyk wrote:
Per Bothner <per@xxxxxxxxxxx> writes:


Since it *optional* static typing, I'm assuming that the specific
operations are "consistent" in the sense of the following example:

If (and (fixnum? x) (fixnum? y))
then: (eqv? (+ x y) (fx+ x y))


It's not the same: (fx+ x y) returns a fixnum even if it overflows.

As I wrote: I'm *assuming* that + when operating on fixnums
will return a fixnum even if it "overflows".

I.e. that arithmetic on fixnums are defined "modularly" and
fixnums are *not* just a subset of the integers.

This implies that (fixnum? 0) is not true, though of course 0
can be trivially *converted* to a fixnum: (fixnum? (as <fixnum> 0))
is true.

I can see that this might be a bit too radical.
--
	--Per Bothner
per@xxxxxxxxxxx   http://per.bothner.com/