Am Dienstag, 3. Mai 2005 17:56 schrieben Sie:
On Fri, Apr 29, 2005 at 06:56:28PM +0200, Daniel Fischer wrote:
So with :a(lso) the old module remains in sight for :n(ames) - and for :i in qualified form. Unfortunately I haven't found a way to use them, Hugs (Nov. 2003) in general refuses qualified names, though with some rather weird behaviour:
Prelude> :l Test Test> :a Char Char> Prelude.map toUpper "buh" "BUH" Char> Data.Char.toUpper 'u' 'U' Char> :i Test.my_map my_map :: (a -> b) -> [a] -> [b]
Char> Data.Char.toUpper 'u' ERROR - Undefined qualified variable "Data.Char.toUpper" Char> Prelude.map toUpper "buh" ERROR - Undefined qualified variable "Prelude.map"
How can it be that Hugs knows these qualified names before I ask about Test.my_map but not afterwards?
Hugs discards the import table of a module when switching modules, e.g. with :m. It used to hold on to it, but this cost a lot of space. So the qualified names in scope at the prompt immediately after :load are what the user's guide says, but they disappear when you switch modules. Unfortunately :i is also implemented using module switching.
Hm, I don't quite get it. Apparently whenever I ask :info Qualified.name with a qualification different from the top module, I lose all qualified names, even from explicitly imported modules -- right? Okay, that's not a problem, only a little odd. Now I encountered another odd thing: Char> :l Prelude> :a Char Char> :a Test Char> :l -- notice the top module is still Char! Prelude> :a Test Test> :a Char Char> in that session, this behaviour was reproducible, in later sessions it wasn't: Prelude> :a Char Char> :a Test Test> :l Prelude> :a Test Test> :a Char Char> :l Prelude> :a Char Char> :a Test Test> Any idea how that may come? Cheers, Daniel