Re: frantk / overlapping instances
I also was tring to play with frantk, but after the overlapping problem (that I found a solution in FranTk homepage) I got this problem: Dependency analysis ERROR "D:\Programming\Frantk\src\FranTkSrc\WidgetSetImpl.lhs" (line 518): Undefined qualified variable "T.sameConfig" Any help ? Computer Science Student at UCPel Pelotas, RS - BRAZIL EMail: [EMAIL PROTECTED] Homepage: http://atlas.ucpel.tche.br/~deus/ - Original Message - From: Tom Pledger <[EMAIL PROTECTED]> To: Timothy Docker <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Thursday, August 31, 2000 11:29 PM Subject: frantk / overlapping instances > Timothy Docker writes: > > > > I'm attempting to play with frantk. I found the same problem mentioned > > on deja... but no answer... > > > > When I try and run the demo under hugs, I get... > > > > > > Reading file "/home/timd/src/haskell/frantk/src/FranTkSrc/WidgetSetImpl.lhs": > > ERROR "/home/timd/src/haskell/frantk/src/FranTkSrc/WidgetSetImpl.lhs" (line 64): Overlapping instances for class "Bindable" > > *** This instance : Bindable Canvas > > *** Overlaps with : Bindable (PWidget a) > > *** Common instance : Bindable Canvas > > > > A suggestion for a direct fix would be nice, but I can't attempt to > > work out what the problem is if I don't understand the error. What is > > an "overlapping instance"? > > > > Thanks, > > > > Tim > > > It means that when the system sees a class method of Bindable (I'm > guessing there's one called bind) applied to a value of type Canvas > (which must be a synonym for PWidget something, in order for there to > be an overlap), it can't tell whether it's supposed to use the > implementation from `instance Bindable Canvas' or the implementation > from `instance Bindable (PWidget a)'. > > Hugs has an extension which you can enable on the command line, to > permit overlapping instances as long as one is strictly more specific > than the other, with the more specific instance's implementations > taking precedence. The message "Common instance : Bindable Canvas" > shows that it's applicable. > > HTH > Tom >
frantk / overlapping instances
When I asked about overlapping types, Tom Pledger wrote: > It means that when the system sees a class method of Bindable (I'm > guessing there's one called bind) applied to a value of type Canvas > (which must be a synonym for PWidget something, in order for there to > be an overlap), it can't tell whether it's supposed to use the > implementation from `instance Bindable Canvas' or the implementation > from `instance Bindable (PWidget a)'. > > Hugs has an extension which you can enable on the command line, to > permit overlapping instances as long as one is strictly more specific > than the other, with the more specific instance's implementations > taking precedence. The message "Common instance : Bindable Canvas" > shows that it's applicable. Thanks, not only does it work fine, but I understand a little better. As it turns out the options that hugs seems to need to run frantk are hugs +o -98 -P It might be good if this made it into the frantk documention. Tim
frantk / overlapping instances
Timothy Docker writes: > > I'm attempting to play with frantk. I found the same problem mentioned > on deja... but no answer... > > When I try and run the demo under hugs, I get... > > > Reading file "/home/timd/src/haskell/frantk/src/FranTkSrc/WidgetSetImpl.lhs": > ERROR "/home/timd/src/haskell/frantk/src/FranTkSrc/WidgetSetImpl.lhs" (line 64): >Overlapping instances for class "Bindable" > *** This instance : Bindable Canvas > *** Overlaps with : Bindable (PWidget a) > *** Common instance : Bindable Canvas > > A suggestion for a direct fix would be nice, but I can't attempt to > work out what the problem is if I don't understand the error. What is > an "overlapping instance"? > > Thanks, > > Tim It means that when the system sees a class method of Bindable (I'm guessing there's one called bind) applied to a value of type Canvas (which must be a synonym for PWidget something, in order for there to be an overlap), it can't tell whether it's supposed to use the implementation from `instance Bindable Canvas' or the implementation from `instance Bindable (PWidget a)'. Hugs has an extension which you can enable on the command line, to permit overlapping instances as long as one is strictly more specific than the other, with the more specific instance's implementations taking precedence. The message "Common instance : Bindable Canvas" shows that it's applicable. HTH Tom
