separate compilation [was Re: Global variables?]
Wed, 05 Feb 2003 20:05:56 -0600
Andrew J Bromage <firstname.lastname@example.org> wrote:
> G'day all.
> On Wed, Feb 05, 2003 at 04:16:33PM -0800, Iavor S. Diatchki wrote:
> > why do you think separate compilation is difficult to achieve in
> > Haskell 98?
> Because of type inference over recursive module imports. Determining
> the type of a function may, in general, require inferring types from an
> arbitrary number of other modules, and may require inference to occur
> at the level of granularity of a clique in the import graph, rather than
> at the level of a single module.
> Requiring an implementation to perform static analysis a clique at a
> time is not "separate compilation", because changing something which
> is private to one module may in general require an unbounded number of
> other modules to be recompiled, even if inter-module optimisation is
> turned off.
I'm not sure I follow this. If you change the type of a value exported
from a given module, that's a public change, no? And if you don't, why
should re-compilation be needed?
> Andrew Bromage