On Sat, 2005-03-05 at 22:15 +0100, Sebastian Sylvan wrote:
On Sat, 05 Mar 2005 17:03:38 +0000, Duncan Coutts > module Graphics.UI.Gtk (
qualified module Graphics.UI.Gtk.Button as Button, ...
I like this idea a lot!
Great. We "just" have to persuade other people around here of the same, in particular compiler implementors and the authors of the Hierarchical Modules Addenda.
It wouldn't break existing stuff (would it?), and it really seems like it should already be in there. I mean if you can import and export modules, it doesn't make sense that qualified imports are allowed but not qualified exports.
I think the reason it was not added before is down to the fact that modules don't really export other modules. They just export other modules contents. (Also it was a deliberately conservative extension.) Exporting qualified names doesn't really change that, we're just exporting the contents of a module but with qualified names.
This strategy also allows the library author some control over the library's structure. I might be missing something but this really does look "nice".
You mean it would allow a 'virtual' structure to be exported that does not match the actual internal structure of the library? I suppose that's true. I think this is probably a bonus (so long as library authors use it sensibly). For example in Gtk2Hs, in actual fact we do not have Graphics.UI.Gtk.AboutDialog we have Graphics.UI.Gtk.Windows.AboutDialog That is we have an additional "category" layer. Otherwise we would have all 130 modules directly in the Graphics/UI/Gtk/ directory which we would find much harder to manage. So it would be nice to keep this structure but to export a 'virtual' module structure that does not mention the category. ie: module Graphics.UI.Gtk ( qualified module Graphics.UI.Gtk.Windows.AboutDialog as AboutDialog ... ) where import Graphics.UI.Gtk.Windows.AboutDialog ... Duncan