How does let binding work

Question

I'm new to Haskell and I'm having troubles understanding how the let binding works in the following example:

prefixes :: [a] -> [[a]] 

prefixes xs =
    let prefix n = take n xs
    in map prefix (range (length xs))

'take' function returns a list, so how does this get bind to 2 variables (prefix n)? Or am I totally missing the point here...

Answer 1

You can think of let as syntactic sugar for using an anonymous function.

let name = value in stuff is equivalent to (\\name -> stuff) value . An anonymous function whose body is the expression in the in clause is applied to the expression bound to a name in the let clause.