type/constructor namespace bug

[duncan.coutts@…]

I tried to compile the Gtk2Hs code generator with hugs (September 2006) and it complained about this bit of code:

extractAPI :: Xml.Document -> API
extractAPI (Xml.Document _ _ (Xml.Elem "api" [] namespaces) _) =

The message is:

ERROR "./Api.hs":156 - Illegal type "Document -> API" in constructor application

Commenting out the type signature suppressed the error.

The problem seems to be a mixup in what namespace Xml.Document is being looked up in. There is both a type Xml.Document and a constructor Xml.Document. The type name seems to be masking the constructor name. It may also be because it's a qualified import. I don't know, I've looked into that any further.

The Gtk2Hs code generator is here:  http://darcs.haskell.org/gtk2hs/tools/apiGen/

You only need the Api.hs module to reproduce the error, though you would need all the .hs files in that dir to get the whole thing to run of course.

[duncan.coutts@…]

The March 2005 version does not have this bug.

[ross]

hugs +k reports:

ERROR "Api.hs":156 - Kind error in constructor application
*** expression     : Document -> API
*** constructor    : Document
*** kind           : * -> *
*** does not match : *

The Document type changed kind in Sep 2005 ( rev. 1.6 of Text.XML.HaXml.Types)

[duncan.coutts@…]

Oh yes. Sorry, my confusion not hugs'.