I want to apply a 3 argument function in different ways based on a boolean value (one of the arguments).
I'd like to be able to apply it in an infix manner so I can chain it (example below). something like the following but that actually works.
f :: Bool -> a -> a -> a
f True i j = i
f False i j = j
... y `(f True)` z `(f False)` b
Do I need to have the Bool as the second variable? Or something else? I'm kind of lost.
P.S. the reason I wanted to do this was to have optional append function
The infix notation for functions with more than two arguments is possible but not very nice. In your case, given
f :: Bool -> a -> a -> a
f True i j = i
f False i j = j
you can write
(True `f` 1) 3
It's much easier (as suggested by others) to write:
let ft = f True
let ff = f False
then you can do
1 `ft` 3 `ff` 5
If you want to use f you should write:
(False `f` ((True `f` 1) 3)) 5
You can verify that
1 `ft` 3 `ff` 5 == (False `f` ((True `f` 1) 3)) 5