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Some thoughts... David Rush (21 Nov 2001 19:26 UTC)
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Bad things Re: Some thoughts...
Jussi Piitulainen
(21 Nov 2001 20:25 UTC)
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Re: Bad things Re: Some thoughts...
David Rush
(22 Nov 2001 16:10 UTC)
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Access time of elements Re: Bad things []
Jussi Piitulainen
(27 Nov 2001 10:59 UTC)
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Re: Access time of elements Re: Bad things []
Per Bothner
(27 Nov 2001 17:10 UTC)
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Re: Access time of elements Re: Bad things []
David Rush
(27 Nov 2001 17:25 UTC)
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Re: Access time of elements Re: Bad things []
Per Bothner
(27 Nov 2001 17:55 UTC)
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Re: Access time of elements Re: Bad things []
David Rush
(27 Nov 2001 21:19 UTC)
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Re: Access time of elements Re: Bad things []
Jussi Piitulainen
(28 Nov 2001 15:40 UTC)
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Re: Access time of elements Re: Bad things []
Jussi Piitulainen
(28 Nov 2001 16:20 UTC)
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Re: Access time of elements Re: Bad things []
Noel Welsh
(28 Nov 2001 10:55 UTC)
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Re: Access time of elements Re: Bad things []
Jussi Piitulainen
(28 Nov 2001 17:21 UTC)
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I have just scanned through the SRFI document and a fair bit of the
discussion. Just two quick thoughts.
1) (array-set! a dim0 dim1 ... dimn val) is a *really* bad specification
for this API. Yes, I know it's compatible with vector-set!, but
it's still not right. This form is deeply inefficient, requiring
list packaging of the dimensions (because of the variable length
argument list) *and* the value to be placed in the array is bundled
into the same data structure as the indicies.
either of the following is far better:
1 (array-set! a val dim0 dim1 ... dimn)
2 (array-set! a (array-index dim0 dim1 ... dimn) val)
I like 2 because of symmetry with the array-shap concept. Also it
has the nice possibility of allowing assignments to larger units of
the underlying array than just single elements.
2) The SRFI should be a completely abstract proposition. There are so
many different array implementations that might be desirable in a
given application that what I really want is an interface over
which I can parameterize other functions. then I use the builtins
for small-scale tests and move up to more efficient implementations
for production (I am specifically thinking of numerical & graph
applications here where sparse arrays/matrices can be very common).
This means that any vector/array equivalence is a *bad thing* IMO.
Preserve disjointness!
david rush
--
Christianity has not been tried and found wanting; it has been found
difficult and not tried.
-- G.K. Chesterton