Functions

Functions are reusable blocks of code that perform specific tasks.

Function Declaration

To declare a function, use the fn keyword followed by the function name. Let’s define a function that greets a user:

import "std/io";

fn greet() {
    io::Println("Hello!");
}

Function Parameters

Functions can take inputs from outside which are called parameters. Parameters are just like variables that are defined in the function signature.

import "std/io";

fn greet(name: str) {
    io::Println("Hello, " + name);
}

Calling Functions

import "std/io";

let message := greet("World");
io::Println(message);  // Hello, World

Return Types

Functions can return values:

fn add(a: i32, b: i32) -> i32 {
    return a + b;
}

let sum := add(5, 3);  // 8

Void Functions

Functions that don’t return a value:

import "std/io";

fn log_message(msg: str) {
    io::Println("[INFO] " + msg);
}

Unnamed or Anonymous Functions

Functions are first-class values in Ferret and can be assigned to variables or passed as arguments. We can define unnamed functions using the fn keyword without a name:

let square = fn(x: i32) -> i32 {
    return x * x;
};

let result = square(5);  // 25

This allows for greater flexibility in how functions are used and composed. See the Anonymous Functions page for detailed examples.