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Comment by andrewflnr | Hacker News Reader

I like the array type syntax: an array of five ints is

  int*int*int*int*int === int^5

instead of something like int[5]. Lots of interesting little ideas.

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How is

    int*int*int*int*int

or even

    int^5

better than a plain int[5]? To me, the use of mathematical operators * and ^ causes dissonance.

If you're coming from a type theory background (which, granted, few are), this operator is actually perfectly natural.

http://en.wikipedia.org/wiki/Product_type

I don't come from much of a type theory background. I certainly have no formal education in the field. I just know how a Cartesian product works, and that's enough to make me get it.

Aren't product types just tuples, whereas arrays correspond to list types? The '^' operator can only construct arrays whose elements are of a single type, right?

That's correct. However, somewhat problematically, Felix considers the tuple int * int to actually be an array int ^ 2. It's not entirely clear this "automatically applied isomorphism" is a good idea though. However it means arrays "drop out" of the notion of a tuple as a special case.

Internally such arrays have a special representation which allows arrays of 100,000 values, something which could never be represented by a tuple type (and still get reasonable compile times :)

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