Re: [Caml-list] Sumtypes of records

["Marcin 'Qrczak' Kowalczyk" <qrczak@knm.org.pl>]

Dnia sob 17. maja 2003 03:35, Chris Hecker napisał:

> It has type { age : int; }, just like int * int has type int * int and
> doesn't need a name.  Does the record need a name for some other reason?

let foo x = x.bar
What is the type of foo if there is no named record in scope having field bar?

I don't say that I like it but it's a consequence of the OCaml's type system. 
Haskell has that too (but theoretically type classes could be made to help). 
SML is what you would like; it has sort of overloading of certain builtin 
operations and in this case requires the type of x to be statically known 
somehow. There is no problem with dynamically typed languages, and 
"non-functional" statically typed ones require to explicitly write the type 
of bound variables anyway. Having the same field name in various record
types just doesn't mix well with type inference.

-- 
   __("<         Marcin Kowalczyk
   \__/       qrczak@knm.org.pl
    ^^     http://qrnik.knm.org.pl/~qrczak/

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