[Haskell] Re: [Haskell-cafe] Why functional programming matters
Alex Young
alex at blackkettle.org
Sun Jan 27 05:37:25 EST 2008
Isaac Dupree wrote:
> Derek Elkins wrote:
>> and you can have
>> unboxed values in dynamically typed languages.
>
> really? Sure that's possible as an optimization, but I thought that to
> explicitly specify that would require a known static type. Or perhaps
> the bit-"tagging" by which some Scheme implementations are able to hold
> small integers without a pointer (IIRC)?
That's exactly what Ruby does - symbols, Fixnums (integers that fit into
a single machine word), bools and nil are unboxed, distinguished from
boxed types by the lowest 2 bits. That's undistinguishable at runtime,
though - everything Just Works as though they're ordinary objects,
including flipping integer class to Bignum (which is boxed) as necessary.
--
Alex
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