John Lato wrote:
This actually clears up something that's been bothering me for some
time. I've never really like syntax of types for functions with
multiple arguments. Using the same token, "->", to separate both
arguments and the result seems very poor, because when reading a type
you don't know if the value after that token is another argument or
the final result without going further ahead. However, knowing that a
function takes exactly one argument makes the syntax seem much more
expressive for me.
Right. This is because -> doesn't separate arguments from each other. It
separates the one and only argument from the one and only result:
a -> b -> c -> d
Has one argument of type 'a' and returns one result,
of type 'b -> c -> d'
The syntax is therefore consistent and uniform if a bit surprising at
first glance.
It turns out that we can usefully think of this as having three
arguments and one result, but it doesn't really. It has one argument and
one result. (It's just the result itself takes arguments!)
Jules
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