Re: [Caml-list] Is a Cow an Animal?

[Pixel <pixel@mandrakesoft.com>]

Jacques Garrigue <garrigue@kurims.kyoto-u.ac.jp> writes:

[...]

> > which type "[> `Beef | `Dead_rabbit | `Dead_human] -> bool" doesn't allow 
> >   is_meat_ (food : [`Grass])
> 
> This is to avoid _too_ weak typings, which would allow for bad typos.
> The more direct solution is
>   let is_meat_ = function
>     | #meat_kind -> true
>     | #vegetable_kind -> false

ok

> > all i got is
> >  new_human : int -> ([ `Dead_human], _[< food_kind]) animal
> 
> Classical solution is eta-expansion
>   let new_human n : ([`Dead_human],  [< food_kind ]) animal =
>     new animal `Human  `Dead_human n
> should work.

/me is bad, i should have thought about this :-(

alas, it doesn't solve the real problem, it just moves it one step later:

# new_human 300;;
- : ([ `Dead_human], _[< food_kind]) animal = <obj>


thanks.
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