Elm Language Functions and Partial Application
Syntax
- -- defining a function with no arguments looks the same as simply defining a value
language = "Elm" - -- calling a function with no arguments by stating its name
language - -- parameters are separated by spaces and follow the function's name
add x y = x + y - -- call a function in the same way
add 5 2 - -- partially apply a function by providing only some of its parameters
increment = add 1 - -- use the |> operator to pass the expression on the left to the function on the right
ten = 9 |> increment - -- the <| operator passes the expression on the right to the function on the left
increment <| add 5 4 - -- chain/compose two functions together with the >> operator
backwardsYell = String.reverse >> String.toUpper - -- the << works the same in the reverse direction
backwardsYell = String.toUpper << String.reverse - -- a function with a non-alphanumeric name in parentheses creates a new operator
(#) x y = x * y
ten = 5 # 2 - -- any infix operator becomes a normal function when you wrap it in parentheses
ten = (+) 5 5 - -- optional type annotations appear above function declarations
isTen : Int -> Bool
isTen n = if n == 10 then True else False
