How would one implement a function that started with an int, and subtracted 1 from it for every time (going through a finite number of possibilities) one of several (for example, 5) boolean values returned 1.
How this would ideally look look is:
function list1 list2 = num
where
num = 4
- (condition from var1 = true)
- (condition from var2 = true)
- (so on, so forth as long as needed)
I have tried implementing these lines similarly to:
num = startVal
- (list1conditional == desiredVal)
- (etc)
But this is returning type errors.
Bool is an instance of Enum: you can enumerate the two values of a Bool: False, and then True.
As a result, it implements the fromEnum :: Enum a => a -> Int, a function that maps a value of an Enum type to an Int: for a Bool, it maps False to 0, and True to 1.
So we can use this like:
result = 5 - fromEnum cond1 - fromEnum cond2
Or for example with a list of conditions:
result = 5 - sum (map fromEnum [cond1, cond2, cond3])
where cond1 and cond2, etc. are expressions of type Bool.