* polymorphic variants, long form
@ 2009-01-20 17:37 Jacques Carette
2009-01-20 17:39 ` [Caml-list] " Luc Maranget
0 siblings, 1 reply; 4+ messages in thread
From: Jacques Carette @ 2009-01-20 17:37 UTC (permalink / raw)
To: caml-list
What is the proper 'long name' of a polymorphic variant?
module S = struct type a = [`Foo of int] end
How do I refer to `Foo without opening S? Both S.`Foo and `S.Foo are
syntax errors.
Jacques
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Caml-list] polymorphic variants, long form
2009-01-20 17:37 polymorphic variants, long form Jacques Carette
@ 2009-01-20 17:39 ` Luc Maranget
2009-01-20 18:04 ` Jacques Carette
0 siblings, 1 reply; 4+ messages in thread
From: Luc Maranget @ 2009-01-20 17:39 UTC (permalink / raw)
To: Jacques Carette; +Cc: caml-list
> What is the proper 'long name' of a polymorphic variant?
> module S = struct type a = [`Foo of int] end
>
> How do I refer to `Foo without opening S? Both S.`Foo and `S.Foo are
> syntax errors.
>
> Jacques
'Foo does the job, it does not refer to any previous type definition.
% ocaml
Objective Caml version 3.11.0
# `Foo;;
- : [> `Foo ] = `Foo
-- Luc
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Caml-list] polymorphic variants, long form
2009-01-20 17:39 ` [Caml-list] " Luc Maranget
@ 2009-01-20 18:04 ` Jacques Carette
2009-01-21 9:39 ` Romain Bardou
0 siblings, 1 reply; 4+ messages in thread
From: Jacques Carette @ 2009-01-20 18:04 UTC (permalink / raw)
To: Luc Maranget; +Cc: caml-list
Luc Maranget wrote:
>> What is the proper 'long name' of a polymorphic variant?
>> module S = struct type a = [`Foo of int] end
>>
>> How do I refer to `Foo without opening S? Both S.`Foo and `S.Foo are
>> syntax errors.
>>
>> Jacques
>>
>
> 'Foo does the job, it does not refer to any previous type definition.
>
> % ocaml
> Objective Caml version 3.11.0
>
> # `Foo;;
> - : [> `Foo ] = `Foo
>
Just a few minutes after I sent my email, I remembered the answer
myself: unlike normal variants, polymorphic variants are not scoped but
affect the namespace in a GLOBAL way. Both extremely convenient and
non-modular at the same time.
Jacques
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Caml-list] polymorphic variants, long form
2009-01-20 18:04 ` Jacques Carette
@ 2009-01-21 9:39 ` Romain Bardou
0 siblings, 0 replies; 4+ messages in thread
From: Romain Bardou @ 2009-01-21 9:39 UTC (permalink / raw)
To: Jacques Carette; +Cc: Luc Maranget, caml-list
Jacques Carette a écrit :
> Luc Maranget wrote:
>>> What is the proper 'long name' of a polymorphic variant?
>>> module S = struct type a = [`Foo of int] end
>>>
>>> How do I refer to `Foo without opening S? Both S.`Foo and `S.Foo are
>>> syntax errors.
>>>
>>> Jacques
>>>
>>
>> 'Foo does the job, it does not refer to any previous type definition.
>>
>> % ocaml
>> Objective Caml version 3.11.0
>>
>> # `Foo;;
>> - : [> `Foo ] = `Foo
>>
> Just a few minutes after I sent my email, I remembered the answer
> myself: unlike normal variants, polymorphic variants are not scoped but
> affect the namespace in a GLOBAL way. Both extremely convenient and
> non-modular at the same time.
It does not actually affect the namespace, as there is no namespace for
polymorphic variants. All variant names can be used, anywhere, and then
types are inferred. Your type definition S.a does not declares anything
but S.a, which is just a type abbreviation and could be expanded to
[`Foo of int] everywhere.
--
Romain Bardou
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-01-21 9:38 UTC | newest]
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2009-01-20 17:37 polymorphic variants, long form Jacques Carette
2009-01-20 17:39 ` [Caml-list] " Luc Maranget
2009-01-20 18:04 ` Jacques Carette
2009-01-21 9:39 ` Romain Bardou
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