ghc and hierarchical module names

[Simon Marlow]

[ thread moved from glasgow-haskell-users@haskell.org to
libraries@haskell.org ]

> "Simon Marlow" <simonmar@microsoft.com> writes:
>=20
> > You must give the full module name in the header, eg.
>=20
> > 	module A.B.C where
>=20
> This surprised me somewhat, and I must have missed any
> discussion/rationale.  Could you elaborate/point me at the relevant
> information?=20

The discussion was on libraries@haskell.org (take a look at the
archives), and the motivation was to make the smallest change possible
to Haskell itself.  With the current proposal, no changes are required
to the Haskell report except for the 1-character change required to the
lexical syntax of module names.

I agree that it might be useful to be able to abbreviate module names by
leaving out an initial prefix, so that entire subtrees can be moved
without changing the source code.  However, there are reasons why this
approach is not so nice:  as you point out, this introduces a dependency
between the source code and the external environment, such that the
meaning of a program depends on the directory layout and options to the
compiler (currently the meaning depends on just the source to the
collection of modules constituting the program), and also there is an
inconsistency in that you would declare a module as 'C' but import it as
'A.B.C'.

Cheers,
	Simon