Functions

Functions are fundamental building blocks in programming. They allow you to encapsulate code into reusable units, making your programs more modular, readable, and maintainable. This documentation covers the syntax, usage, and various features of functions in Eiger.

Defining Functions

To define a function, use the func keyword followed by the function name and parentheses. To close the function body use end

Syntax

func functionName(parameters)
    ~ function body
end

Example

func greet(name)
    emitln("Hello, " + name + "!")
end

Function Parameters

Functions can accept parameters, which are values passed into the function. Parameters are defined within the parentheses in the function declaration.

Syntax

func functionName(param1, param2, ...)
    ~ function body
end

Example

func printAge(name, age)
    emitln(name + " is " + age + " years old")
end

Return Values

Functions can return a value using the ret statement. If no return statement is provided, the function returns nix (i.e null in C#)

Syntax

func functionName(parameters)
    ret value
end

Example

func add(a, b)
    ret a + b
end

Scope and Closures

Variables declared inside a function are local to that function. Functions can also create closures, which are functions that capture and remember the environment in which they were created.

func createCounter()
    let count = 0

    ret func()
        count += 1
        ret count
    end
end

counter = createCounter()

emitln(counter()) ~ 1
emitln(counter()) ~ 2
emitln(counter()) ~ 3

Higher-Order Functions

Higher-order functions are functions that take other functions as arguments or return them as results. They are a key feature of functional programming.

func applyFunction(fn, value)
    ret fn(value)
end

func cube(x)
    ret x ^ 3
end

emitln(applyFunction(cube, 3)) ~ 27