Yes of course because the parameters are usually designed with currying in mind, so the order is from most general on the left to the most specific on the right. In the case of elem, both orders are reasonable, but often times only one makes sense and then it is easy to remember.
The point of my comment was more that one of the beauties of Haskell is that positional arguments are made so elegant because every positional argument is accompanied by a type. I wasn't making a statement about the order of parameters themselves, but how all parameters are typed.
> In the case of elem, both orders are reasonable, but often times only one makes sense and then it is easy to remember.
In some languages where callbacks taking positional arguments are idiomatic (like Javascript), untyped functions can cause a lot of problems by making it really hard to discern/remember what gets passed in where. In Haskell, there's often very little onus on the developer to remember anything at all; the type system will make sure they got the order right.
Obvious exceptions are non-associative functions of the type
a -> a -> a
You mean "non-commutative"
> For example, the Haskell function elem returns whether an element exists in a list. Do you call it with the list first or thing to search? There's no way to know.
Well, the type of `elem` is
So, it is - with practice - clear to see that the singular item comes first, and the item in the foldable container comes second. Perhaps this sort of Type-Driven Development, which is more of a practical mindset than language feature, isn't emphasized in the (excellent) books from which the author was learning...but it becomes an invaluable tool in Haskellers' toolboxes while trawling through package documentation later on. Many times, between the name of the function and type of arguments, one can figure out exactly what they need to pass in to achieve the desired output.