Ink by Example — Functions

Ink by Example: Functions

Functions are the building blocks of Ink and enable us to write terse functional code.
	std := load('../vendor/std') log := std.log
Functions are created with the arrow `=>` symbol.	shout := (word) => word + '!' log(shout('Hello')) multiply := (x, y) => x * y log(multiply(2, 8))
When a group of expressions follow the arrow symbol, the result of the final expression is the return value.	` single argument parentheses are optional` sayAndMultiply := num => ( log('About to multiply ' + string(num) + ':') ` the return value ` num * num ) log(sayAndMultiply(8))
Function invocation `()` takes precedence over property-access `.` — instead of `obj.func(argument)`, we use `(obj.func)(argument)`.	math := { swapSign: n => 0 - n } weight := (math.swapSign)(100) log(weight)
Here's an example of tail recursion.	factorial := n => n :: { 0 -> 1 _ -> n * factorial(n-1) } log(factorial(5))
It's natural to use closures — functions that have access to the parent scope after the parent function has closed.	makeMultiplier := x => ( y := y => x * y ) multiplySeven := makeMultiplier(7) multiplyTwenty := makeMultiplier(20) log(multiplySeven(2)) log(multiplyTwenty(4))
Functions that immediately evalute and return another function is called currying in functional programming land.	greeting := a => b => a + ' ' + b message := greeting('Hello there,')('General Kenobi') log(message)

$ ink functions.ink
Hello!
16
About to multiply 8:
64
-100
120
14
80
Hello there, General Kenobi

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