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When functional languages can be accepted by industry?
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Dennis (Gang) Chen
- Jean-Christophe Filliatre
- John Max Skaller
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| Date: | -- (:) |
| From: | Christophe Raffalli <Christophe.Raffalli@u...> |
| Subject: | Caml wish list |
Here is a list of request for Ocaml that would really make the libray for formal and numerical calculus better (see http://www.raffalli.univ-savoie.fr/~RAFFALLI/formel.html) : - include with ... would allow multiple inheritance in signature ! - include in structure. We should also think about multiple inheritance and even override in this case. But a simple implementation would already be useful. - typing of structure containing modules is problematic: if you write: module F = functor(M:M) -> struct module M =M end Then you have a module Q:Q where Q is a subtype of M. If you type R = F(Q) then the type of R.M is M even if the type system knows that R.M = Q. This makes it impossible in some cases to put modules as member of structure ! It was for instance impossible to put the Ring of scalar as a member of the structure Vector, because when this Ring is a Field, we may loose this information and fail to type-check perfectly correct program. - Infix operator like + ... Every body will agree that infix operator are needed. So R.+ should be allowed as an infix operator and R.(+) would be prefix. One could event think to reuse symbols like + for many functions. Here is a simple proposal on how to do it that I would really enjoy to see working : Two new commands in OCaml structure (the syntax can be changed): share + : 'a -> 'a -> 'a this makes that + exists and is type-checked with type 'a -> 'a -> 'a share + = add_int share + = add_float ... this means that, after type checking, + will take the first value among add_int, add_float, ... whose type matches the infered type for +. If add_int is tested first, this will be compatible with existing code. This is easy to implement (I think). One could even allow some kind of recursive macros ! share + = fun (x,y) (x',y') -> (x+x', y+y') share + = List.map2 (+) share + = Array.map2 (+) This is a bit mode difficult to implement, but it seems feasible. - The library is too slow when using floating points. One need to add inlining for functor and functions before doing the floating point optimisations. A function or functor that is used only once should be inlined regardless of its size (no huge code size explosion even if the function is used once in every .ml files) A syntax for inlining on demand (when applying and/or) defining the function should be provided. A way would be to have three new choices when defining a function or functor: - normal - always inlined - inlined on demand -- Christophe Raffalli Université de Savoie Batiment Le Chablais, bureau 21 73376 Le Bourget-du-Lac Cedex tél: (33) 4 79 75 81 03 fax: (33) 4 79 75 87 42 mail: Christophe.Raffalli@univ-savoie.fr www: http://www.lama.univ-savoie.fr/~RAFFALLI