Export lists in modules

Wolfgang Jeltsch wolfgang at jeltsch.net
Wed Feb 22 15:59:52 EST 2006

Am Mittwoch, 22. Februar 2006 18:27 schrieb Malcolm Wallace:
> [...]

> > But you don't need to go so far as to indicate the difference between
> > type/data/newtype - just differentiating classes from tycons is enough to
> > separate the namespaces. 
> Yes.  However it could be slightly confusing that one writes "newtype"
> in the module body, but "data" in the module header?

But whether a type is declared by data or by newtype is an implementation 
detail, so this distinction shouldn't be made in a part of the code which is 
supposed to specify an interface.  On the other hand, if you export 
constructors too, the distinction between newtype and data might be 

> [...]

> > BTW, I think Simon PJ was asking about how to *declare* types &
> > classes in export lists, given that you're adding signatures to export
> > lists which are a kind of declaration.  If you want to put more of the
> > interface into the export list, shouldn't you put it all in?
> Yes, I see the point.  In the fullness of time, perhaps we will indeed
> specify the module interface in full, including datatype definitions.

Only those parts of datatype definitions which are exported.  And we would 
have to include fixity declarations too.

> [...]

> Regards,
>     Malcolm

Best wishes,

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