Terbium

An unfinished compiler for the Terbium programming language.

Specification

A semi-formal language specification can be found here. The specification may be outdated with this specific implementation.

Why (do I want to make) Terbium?

Terbium is designed to be:

• Concise. Write less code wherever possible. High-level constructs and language features make Terbium elegant to write.
• Readable. Being explicit and unambiguous in the code where needed while still being concise.
• Simple. Complexity is abstracted away from the developer when writing a Terbium program, but low-level features are still accessable whenever needed.
• Performant. With LLVM, Terbium can compile to optimized native machine code, so your high-level code won’t compromise runtime performance. All abstractions in Terbium incur zero runtime overhead.
• Robust. Write error-free code with Terbium. Null is a concept that does not exist in Terbium, and all errors must explicitly be handled. Mutability is explicit and memory is automatically freed.
• Rapid. Rapid-prototyping and developer experience is just as important as runtime performance. A debug mode compiles semi-optimized code that compiles fast and suppresses pedantic errors as warnings.
• Typed. A comprehensive type system allows Terbium to infer the types of most values and functions at compile-time. If a type cannot be inferred, it must be explicitly specified.

Examples

Hello, world!

// Main function is recommended but not required
func main() {
    println("Hello, world!");
}

Fibonacci

func fib(n: uint) = if n <= 1 then n else fib(n - 1) + fib(n - 2);

func main() {
    (0..=10).map(fib).for_each(println);
}

Optional values

// Optional values are of type T? and can be either some(value) or none
// Any `value` of type T can coerce into T? by some(value).

func maybe_five() -> int? = none;

func main() {
    println(maybe_five() else 10); // 10
}

Error handling

import std.io.{Error, stdout};

// T throws E is a type itself:
type Result<T> = T throws Error;

// throws E expands to void throws E, void being the unit type
type VoidResult = throws Error;

// Specify the return type as `throws Error` to indicate that the return value might fail
func fallible() -> throws Error {
    let mut out = stdout();
    out.write("This might fail")!; // use ! to propagate the error to the function

    // implied return value of `void` is coerced to `ok(void)`
    // in fact, any `value` of type T can be coerced to `T throws _` as `ok(value)`
    //
    // this explicit type cast will result in `ok(5)`:
    // let x = 5 to /* `to` is the cast operator */ int throws Error;
}

func main() {
    // Use `catch` to handle a fallible value
    fallible() catch err {
        eprintln($"Failed to print: {err}"); // string interpolation
    };

    // If there is absolutely no way to handle an error,
    // you can halt the program's execution with `panic`:
    //
    // Note: `else` is equivalent to `catch _`
    fallible() else panic("Oh no!");
    // You can also use `.unwrap()` to panic with no message:
    fallible().unwrap();
}

Functional programming

/// Calculate double the sum of all multiples of 3 which are <= n
func example(n: uint) =
    (0..=n)
        .filter(\x do x % 3 == 0) // Lambda expressions
        .map { _ * 2 } // Shorthand for .map(\x do x * 2)
        .reduce { $0 + $1 } // Shorthand for .map(\x, y do x + y)
        |> println; // Pipeline operator 

Subtyping

// A `struct` defines a type that is composed of many values called "fields", 
// which are all stored in a contiguous block of memory. 
// Each field is given a name and a type.
struct Rectangle {
    width: int,
    height: int,
}

// Explicit nominal subtyping with traits.
//
// A `trait` defines a set of functions that a type must implement.
// It is similar to an interface in object-oriented languages.
trait Shape {
    // A shape must have an `area` method that returns an `int`.
    func area(self) -> int;
}

// A `extend` block can extend a type's functionality with a trait.
// The type must implement all functions defined in the trait.
extend Shape for Rectangle {
    /// Calculate the area of the rectangle.
    func area(self) = self.width * self.height;
}

func main() {
    // Create a new rectangle using the generated constructor.
    let rect = Rectangle(width: 10, height: 5);
    
    // Call the `area` method on the rectangle.
    println(rect.area()); // 50
}