search path wierdness

[Malcolm Wallace]

"Simon Marlow" <simonmar at microsoft.com> writes:

> > Now presumably the gtk/Graphics/UI/Gtk/General/Signals.hi file
> > remembers the module name. So ghc reads the module name from
> > gtk/Graphics/UI/Gtk/General/Signals.hi and then for some reason looks
> > for Signal.hi which of course it cannot find.
> 
> I don't quite follow.  When compiling
> gtk/Graphics/UI/Gtk/General/Signals.hs did you specify -ohi
> gtk/Graphics/UI/Gtk/General/Signals.hi?

I think the problem is probably slightly more convoluted.  When one
module M exports entities from another N, ghc does not copy the
relevant entities into the interface file for M, but rather plants
a pointer to the interface for N, yes?

So I think probably a module like Graphics.UI.Gtk.Foo is importing
and re-exporting from Graphics.UI.Gtk.Signals.  Because, and only
because, the file Signals.hi is in the directory Graphics/UI/Gtk,
the import works.  But the re-export is notated in Foo.hi as module
Signals, rather than Graphics.UI.Gtk.Signals, because that is what
the file Signals.hi claimed as its true module name.

Then, a module in a different directory, let's say Graphics.Bar,
imports Graphics.UI.Gtk.Foo, discovers a need for module Signal,
and cannot find it.

Regards,
    Malcolm