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[Caml-list] Why are arithmetic functions not polymorph?
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| Date: | -- (:) |
| From: | brogoff@s... |
| Subject: | Re: [Caml-list] Why are arithmetic functions not polymorph? |
On Fri, 23 May 2003, Brian Hurt wrote: > On Fri, 23 May 2003 brogoff@speakeasy.net wrote: > OK. I'm reading the readme. First off, congratulations, you're dodging a > lot of the bullets that C++ didn't. > > Here's a question. Consider the following code: > > generic one = | int => 1 | float => 1.0 > > generic two = | int => 2 | float => 2.0 > > generic plus = | int -> int -> int = (+) > | float -> float -> float = (+.) > > plus one two;; > > What's the result? Is it the int 3, or the float 3.0? Syntax error ;-) Fixing that, the int 3. Like pattern matching, if the first matches, that wins. If you reorder, you can make it return float. > Another problem already arises with the generic (aka overloaded) > comparisons- you oftentimes need to arbitrarily specify types in order to > replace the expensive call to the generic compare with a much cheaper > inlined type-specific compare. If you start having to specify types a lot > more often, that reduces the advantage of having type inference. I don't see that as too much of a problem, but maybe with more experience my opinion will change. > > New operators are not sufficient, and SML is more powerful in it's ability to > > define new operators than OCaml (minus CamlP4) is. > > Yeah- I'd like to be able to define accessor operators somehow. Say being > able to define $[ ] as hashtbl lookups, so that h$[3] ==> Hashtbl.find h > 3. Pierre Weis alluded to this desire in an ealier discussion of generics. -- Brian ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners