[racket] Immutable vectors

On 9/5/13 10:42 AM, Konrad Hinsen wrote:
> Neil Toronto writes:
>
>   > FWIW, `vector->immutable-vector' is pretty fast. It's usually the least
>   > significant part of an O(n) operation. Its two biggest problems are that
>   > it allocates memory and annoys people.
>
> That's a good summary of my first impressions ;-)
>
>   > If you're working in Typed Racket, you might consider using the
>   > `math/array' library. It provides multidimensional arrays with O(1)
>
> It's on my radar for when I move on to exploring Typed Racket. The
> concept looks very interesting, with many idea's from Haskell's REPA,
> except that it's in a language I can actually use to do something
> useful.
>
>   > to do something similar: have library functions operate on mutable
>   > vectors, with user-facing functions accepting and receiving immutable
>   > vectors, or some more abstract wrapper data type. The `math/matrix'
>
> That's certainly doable, but it looks like a lot of overhead for using
> a very basic data structure.
>
>
> Scott Klarenbach writes:
>
>   > Check out some of the functional data structures found here:
>   >
>   > http://www.ccs.neu.edu/racket/pubs/sfp10-kth.pdf
>   >
>   > VLists may be of particular interest in your case.
>
> That's the stuff in the pfds package, right?
>
>    https://pkg.racket-lang.org/info/pfds
>
> Interesting indeed, makes me think of Clojure vectors. And written to
> be used as a drop-in replacement for lists. I'll play with that as
> well!
>
> The implementation is in Typed Racket as well, so should I expect the
> same performance problems as with arrays when I work in plain Racket?

Thee is also this:

    https://pkg.racket-lang.org/info/ralist

Which is not written in typed racket and has an un-contracted form for 
efficiency.

David