Language Tour

Welcome to the goose language tour! This tour will introduce you to the basic concepts of goose and show you how to write your first goose program. Let's get started!

Hello, World!

Let's start with the classic "Hello, World!" program. In goose, you can print text to the console using the println function. Here's how you can write the "Hello, World!" program in goose:

println("Hello, World!")

To run the program, save the code to a file named main.goose and run the following command in your terminal:

goose run main.goose

You should see Hello, World! printed to the console. Congratulations! You've just written your first goose program.

Variables

Variables are type-agnostic containers that store data. You can create variables in goose using the let keyword. Give the variable a name and assign it a value using the = operator. Later, you can use the same = operator to change the value stored inside.

let message = "Hello, World!"
println(message)
message = "Goodbye, World!"
println(message)

In this example, we create a variable named message and assign it the value "Hello, World!". We then print the value of the variable to the console. Next, we change the value of the variable to "Goodbye, World!" and print it again.

You can also make final variables using the const keyword. Final variables cannot be reassigned once they are initialized.

const message = "Hello, World!"
println(message)
message = "Goodbye, World!" // Cannot reassign a const variable

For more information on variables and data types in goose, see the Variables section of the language reference.

Comments

Comments are used to document your code and provide context to other developers (or your future self). In goose, comments start with the // characters and continue until the end of the line.

// This is a single-line comment
let message = "Hello, World!" // This is another single-line comment

You can also write multi-line comments using the /* and */ characters.

/*
This is a multi-line comment
that spans multiple lines
*/

Data types

goose comes with several built-in data types that you can use to store different kinds of values. Here are some of the basic ones:

• string: A sequence of characters
• int: A whole number (arbitrary precision)
• float: A floating-point number
• bool: A boolean value (either true or false)
• symbol: A unique identifier
• array: An ordered list of values
• object: An unordered collection of keys and values

For more information on data types in goose, see the Data Types section of the language reference.

Functions

Functions are blocks of code that perform a specific task. You can define functions in goose using the fn keyword. Give the function a name, a list of parameters, and a block of code to execute when the function is called. Function blocks, like with other blocks in goose, are delimited by the end keyword.

fn greet(name)
  println("Hello, $name!")
end

greet("Alice")
greet("Bob")

For more information on functions in goose, see the Functions section of the language reference.

Control flow

Control flow statements allow you to change the order in which your code is executed. goose supports several control flow statements, including if, else, while, and for.

let x = 10

if x > 5
  println("x is greater than 5")
else
  println("x is less than or equal to 5")
end

let i = 0
repeat while i < 5
  println(i)
  i = i + 1
end

// repeats forever, until a break statement is encountered
repeat forever
  println("Hello, World!")
  break
end

// repeats 10 times!
repeat 10 times
  println("Hello, World!")
end

for j in [1, 2, 3, 4, 5]
  println(j)
end

For more information on control flow in goose, see the Control Flow section of the language reference.

User input

goose has a rich standard library which includes functions for reading user input from the console. You can use read() or prompt() from std:readline to read input from the user.

To use them, you'll need to import the std:readline module at the top of the file. Once you do, the readline object will be available for you to use. Then, use a dot to access the read() or prompt() functions.

import "std:readline"

let name = readline.prompt("What is your name? ")
println("Hello, $name!")

There's plenty more in the standard library, so be sure to check out the API Reference for a full list of available modules and functions.

That's the basics

That's it for the goose language tour! You've learned the basics of goose and are ready to start writing your own programs. If you have any questions or need help, feel free to ask in the community. Happy coding!