Elm LanguageFunctions 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

Functions and Partial Application Related Examples

• Infix operators and infix notation
• Lambda expressions
• Local variables
• Overview
• Partial Application
• Strict and delayed evaluation