On Thu, Jan 14, 2010 at 5:19 AM, Ozgur Akgun
Can someone give an example of a "reasonable" function that never uses one of its parameters, and justify the existence of that parameter in this case, please?
As I mentioned, this is not only about parameters, but about type
variables. From my own code:
data Signal y =
Because for this example, f :: _unused -> A -> B f _ a = b I think what I'd do is to write the function f without that first parameter, and call the funcrtion accordingly.
It's common (for me at least) to write 'modify' functions that look like "modify_x :: (X -> X) -> SomeMonad ()". You don't need to write the 'set' variant if you have const. That said, 'const' is already in the Prelude. But ignored args also turn up when you need a common signature, this also occurs a number of times in my own code: this_way :: X -> Y -> Z that_way :: X -> _y -> Z -- doesn't need Ys testing_way :: _x -> _y -> Z ... modify_rec $ const $ rec { rec_doit = if do_this_way then this_way else that_way }