Hello World

The simplest Tova program is a single print call.

Basic Output

Create a file called hello.tova:

print("Hello, World!")

Run it:

tova run hello.tova

Output:

Hello, World!

String Interpolation

Tova supports string interpolation with curly braces inside double-quoted strings:

name = "Tova"
version = 1

print("Welcome to {name}!")
print("{name} version {version} is ready.")

Output:

Welcome to Tova!
Tova version 1 is ready.

Try "Hello World" in Playground

Defining Functions

Use fn to define functions. The last expression in a function body is the return value:

fn greet(name) {
  "Hello, {name}!"
}

print(greet("World"))
print(greet("Tova"))

Output:

Hello, World!
Hello, Tova!

Try "Functions" in Playground

Functions with Logic

Combine functions with match expressions and the pipe operator:

fn fizzbuzz(n) {
  match [n % 3, n % 5] {
    [0, 0] => "FizzBuzz"
    [0, _] => "Fizz"
    [_, 0] => "Buzz"
    _      => "{n}"
  }
}

for n in range(1, 21) {
  print(fizzbuzz(n))
}

Try "FizzBuzz" in Playground

Working with Collections

Tova has a rich standard library for working with lists:

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

// Filter and transform
evens = numbers |> filter(fn(n) n % 2 == 0)
doubled = evens |> map(fn(n) n * 2)
total = doubled |> sum()

print("Evens: {evens}")
print("Doubled: {doubled}")
print("Sum: {total}")

Output:

Evens: 2,4,6,8,10
Doubled: 4,8,12,16,20
Sum: 60

Try "Collections" in Playground

Error Handling with Result

Tova uses Result types instead of exceptions:

fn parse_age(input) {
  n = parseInt(input)
  match n {
    n if n > 0 => Ok(n)
    _ => Err("Invalid age: {input}")
  }
}

match parse_age("25") {
  Ok(age) => print("Age is {age}")
  Err(msg) => print("Error: {msg}")
}

match parse_age("-3") {
  Ok(age) => print("Age is {age}")
  Err(msg) => print("Error: {msg}")
}

Output:

Age is 25
Error: Invalid age: -3

What's Next

• Build a reactive counter with client-side state
• Create a full-stack todo app with server and client
• Explore the CLI reference for all available commands