[ocaml-platform] on the need and design of OCaml namespaces

[Alain Frisch]

On 02/28/2013 11:17 PM, Didier Remy wrote:
>> I agree with your point about settilng deep semantic issues ahead of
>> syntactic one.  I would however submit that the question of whether
>> you should:
>>
>> - Have opens in the language proper, including local opens
>> - Have renames for namespaces in the language proper
>
> Yes, this is  the minimal, and probably agreed on.

I agree with the first point, but not the second one.  In my proposal, 
the only place where a ".ns" mapping file is referred to is the (local) 
open/using statement:

    open namespace Core  (* --->  loads core.ns *)

In this proposal, I don't think it is important to allow writing 
Core#List.map, since Core_List.map is always available.  Since .ns files 
are only "opened", I don't see the point of renaming them:

   alias namespace C = Core
   ...
   open namespace C


What would be useful is an aliasing feature for modules (which could 
serve to explain the meaning of .ns files in my proposal).

> The main question whether namespaces are hierarchical or flat is still not
> answered

I think the question itself assumes that namespaces are a new kind of 
objects (and then we can discuss what is their structure, flat or 
hierarchical, graph with ordered edges, etc).  But again, there are some 
ways to address the needs expressed in this discussion without 
introducing such a notion.  In my proposal, there is one single "space 
of names" for modules and compilation units plus a feature to control 
the mapping of module references to compilation units.  In this context, 
I don't even know how to interpret the question of whether namespaces 
are hierarchical or flat.  This does not mean that this question is 
pointless, only that it pertains only to a given category of solutions 
for the problems we are trying to solve.



Alain