On Mon, Aug 23, 2010 at 11:12 PM, Neil Toronto <[email protected]> wrote: > It works similarly, but it's not the same. Those use the sequence > abstraction; this uses a multidimensional random-access abstraction called > "arrayn". Also, "forall" and "foralln" semantics are meant to be concurrent, > so in principle they can always parallelize the work. Further, arrays are > read/write when their backing models are read/write (e.g. vectors).
This is great stuff. If you're not familiar with Single Assignment C take a look at it. It's the only modern functional language I know that takes arrays seriously. It has an interesting array comprehension system. > At first I tried to use the sequence abstraction. But Sequenceof is a > polymorphic type, so I couldn't get require/typed to import in-vector et al. > I don't want to use sequences now, though. Arrays should be read/write. > Destructive update can be useful in interactive programs like games. > Avoiding allocation reduces GC collects, which reduces stutters and hitches. The example you gave is something that could be written with for/vector. One could equally implement for/vector! that mutates an existing vector. It is really when you move to higher dimensions that for/* variants have problems, as the order you construct the matrix becomes difficult to express. N. _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
