cowan at ccil.org
Tue Mar 24 21:11:17 EDT 2009
Vincent Manis scripsit:
> This whole discussion is making me extremely uncomfortable. In fact,
> my head exploded when I read John Cowan's claim that `Scheme' is
> devoid of operational or denotational meaning.
Don't panic; it was a mere jest, alluding to the fact that R5RS has a
denotational semantics but no operational one, and R6RS has an operational
semantics but no denotational one.
> in a Philip K Dick story who discovers that not only is the universe
> unreal, but so too is the character him/herself.
If he's not real, how can he know if the universe is real or not?
> I know perfectly well what `Scheme' is. It's a somewhat fuzzy set of
> languages that have reasonably common syntax,, semantics, and
> pragmatics. It's quite practical to write portable Scheme code, which
> must therefore mean that the language the author of the code is writing
> in and the language the implementor is implementing must have a
> very high degree of overlap.
So we would hope. But certain people who need not be nameless, for they
have very fine names indeed, have taken it upon themselves to say that
R6RS is not Scheme. It is this attitude I wish to refute.
> the internal representation of C integers are not specified, somebody
> build a replica of an IBM 7094, and we might have sign-magnitude
> integers again!).
C integers can be represented however you like (even as sign-magnitude
bignums) but in certain ways must act *as if* they were two's complement
binary representations: things like casting from signed to unsigned types
and shifting, e.g.
Don't be so humble. You're not that great. John Cowan
--Golda Meir cowan at ccil.org
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