Am Freitag, 29. April 2005 18:01 schrieb Ross Paterson:
On Thu, Apr 28, 2005 at 09:22:15PM -0400, Cale Gibbard wrote:
The second problem arises from hugs not doing the same thing as ghci with respect to looking up qualified variable names (that is, those with the module name specified, in this case, the standard module Char). You can tell hugs to also load the Char module on top of whatever code you have loaded by using the command ":also Char", after which the prompt should look like Char> and you can try toUpper 'a'
Might as well use :load -- in both case Char becomes the new current module, making the old current module inaccessible.
There is a difference, though. Compare Test> :l Char Char> :n my_map ERROR - No names selected and Test> :a Char Char> :n my_map Test.my_map (1 names listed) 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? Puzzled, Daniel