--- Glynn Clements
David Sankel wrote:
Questions :: 1) How does the interface look in Test_midlevel.hs? Is there any critiques in regard to using this style in CGA (Common GUI API)?
1. Widgets aren't being given names. This makes it impossible to refer to them from outside of the code. It also eliminates the possibility of implementing a useable Xt (e.g. Motif) backend. Toolkits which don't name widgets can just ignore the name.
I'm sorry, I don't understand what you mean by "impossible to refer to them from outside of the code". Can you give me an example of what you are talking about.
2. Widget properties (label, position, dimension) are being embedded in the code, which is a bad idea. This point is closely tied in with point 1.
Where should this be in your opinion?
3. Personally, I would prefer a generic widget creation function, rather than a different function for each type of widget. E.g. Xt has XtCreateWidget(), with the widget class being passed as an argument. A more Haskell-ish approach would be to use typeclasses, e.g.:
class Widget a where create :: String -> a -> [Property] -> IO a -- create name parent properties = ...
Why would you prefer this over the other method? One problem with this method seems to be runtime errors for nonexistant classes. David J. Sankel