Claus Reinke wrote:
In general, I think Haskell has too many array libraries, with too
many APIs. And that doesn't even take account the overuse of
unsafe APIs, or the non-integrated type-level safety tricks - if array
accesses were properly optimized, there should be a lot less need for
the extreme all-or-nothing checks or home-grown
alternative special-purpose APIs:
- type-level code for watermarking indices belonging to certain
index sets is one step to eliminate index checks, but hasn't been
integrated into any of the standard libs
- one could also associate index subsets with operations that do
not leave the index superset belonging to an array (eg, if
min<i<max, then min<=i+-1<=max, still safe without checks)
- GHC does seem to common up index checks only if they are
identical, but if min<i<i+1<i+2<..<i+j<max, only the outer checks
are really necessary (as long as we know about '+')
- whole-array ops allow to avoid index checks without type-level
tricks, leaving the indexing implicit; but the corresponding ops
in Data.Array.MArray claim to construct new arrays, contrary
to the intended inplace updating for which one uses MArrays?
- etc. etc.
At least, uvector seems to take multi-element ops more seriously.
But with so many people working on sequential and parallel Haskell
array libraries, I was hoping for someone to take a big ax and clear
out all that sick and half-dead wood, to give a small number of
healthy arrays libs room to grow. Would be a lot easier for us poor naive
Haskell array users who otherwise tend to get lost in that forrest!-)
+3
The current array situation is unecessarily messy - and I prefer
mathematical elegance to ad-hoc mess. (And you think I use Haskell, why
exactly?)
Of course, it's all very well complaining about it... somebody still has
to *do* all this wonderful stuff. :-/
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