On Fri, Aug 08, 2003 at 09:33:23AM +0100, Simon Marlow wrote:
Thinking about it, I'm not sure that the language definition needs to be extended at all, to allow the proposed scheme.
The language definition (with hierarchical modules, of course) continues to specify the meaning of a collection of modules, each with an absolute module name. What we are proposing is two mechanisms that the compilation system can provide so that the user has more flexibility in constructing a set of modules with absolute names.
1. A method by which a module can change its module name after being compiled.
2. A method by which a module can be exposed as several absolute module names to future compilations.
I think these could be expressed as source-to-source transformations, leaving the Haskell 98 + hierarchical modules spec as it is.
I may be misunderstanding the transformations you have in mind, but how do I tell whether A.B.C.f and X.C.f are the same thing? Also, suppose I have the documentation for someone's package, and I'm looking at a program that uses that package, but grafted in at some unknown point in the hierarchy. How do I understand that program? This seems quite different from search paths; all that matters is the text of the modules concerned, not their location in the file system.