[ocaml-platform] Changes to my previous proposal for namespaces

[Yaron Minsky]

Got it.  That matches my initial mental model.  Just to be explicit:

    open namespace Core
    open namespace Async

Will lead to separate opens of the Core and Async Pervasives modules.

I would somewhat prefer more flexibility for auto-open modules (i.e.,
allow for the specification of multiple modules to open, of arbitrary
name, and allow for merge operations to open both, in order, rather
than just one), and I don't really understand why this more limited
version is preferable; but I don't mind enough to fight.  This
solution seems like it would solve the use cases that I am aware of.

y

On Mon, Mar 18, 2013 at 9:28 AM, Gabriel Scherer
<gabriel.scherer at gmail.com> wrote:
> This is fine: it will desugar into:
>
>   open namespace Core
>   open Pervasives (* line produced only if Core#Pervasives exists *)
>   let () = printf "Hello world!\n"
>   open namespace Async
>   open Pervasives (* line produced only if Async#Pervasives exists *)
>   let () = printf "Hello world!\n"
>
> You would be in trouble if you defined a CorePlusAsync namespace as, say
>    include "core.ns"
>    include "async.ns"
>
> and then did
>    open namespace CorePlusAsync
>
> it would desugar into
>    open namespace CorePlusAsync
>    open Pervasives
>
> which is equivalent to
>    open namespace CorePlusAsync
>    open Async#Pervasives
>
> and not
>    open namespace CorePlusAsync
>    open Core#Pervasives
>    open Async#Pervasives
>
> On Mon, Mar 18, 2013 at 1:55 PM, Yaron Minsky <yminsky at janestreet.com> wrote:
>> It occurs to me I just don't understand the semantics of this.  What
>> happens if I do this:
>>
>>     open namespace Core
>>     let () = printf "Hello world!\n"
>>     open namespace Async
>>     let () = printf "Hello world!\n"
>>
>> or, for that matter:
>>
>>     open namespace Core
>>     let () = printf "Hello world!\n"
>>     let open namespace Async in
>>     printf "Hello world!\n"
>>
>> Async and Core have different definitions of printf, as it happens.
>> Which gets called in these cases?
>>
>> y
>>
>> On Mon, Mar 18, 2013 at 8:34 AM, Leo White <lpw25 at cam.ac.uk> wrote:
>>>> Can the case of both Core and Async (and opening both of their
>>>> pervasives modules) be handled here?  This seems to me to be of
>>>> fundamental importance.  If that's missing, then I misunderstood
>>>> the proposal.
>>>
>>> Yes that is fine. It just means that if you made a new namespace by
>>> merging the Core namespace with the Async namespace then the Pervasives
>>> module of one would shadow the Pervasives module of the other.
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