Syntax

Zephyr uses a brace-based syntax inspired by modern systems languages. It is case-sensitive and requires semicolons for statement termination.

Comments

Zephyr supports both single-line and multi-line comments.

// This is a single-line comment

/*
   This is a
   multi-line comment
*/

Keywords

The following words are reserved and cannot be used as identifiers:

fn	let	mut	return	yield	if	else
while	for	in	break	continue	match	struct
enum	trait	impl	import	export	coroutine

Identifiers

Identifiers must start with a letter (a-z, A-Z) or an underscore (_). Subsequent characters can be letters, digits (0-9), or underscores.

let variable_name = 10;
let _privateCounter = 0;
let camelCase = true;

Scoping

Zephyr employs lexical (block) scoping. A new scope is created with curly braces {}. Variables declared within a block are not accessible outside of it. Inner scopes can shadow variables from outer scopes.

let x = 10;
{
    let x = 20; // Shadows the outer x
    print(x);   // Prints 20
}
print(x);       // Prints 10

Semicolons

Every statement must be terminated with a semicolon ;. This includes variable declarations, expressions, and control flow statements inside blocks.

let a = 1;
let b = 2;
print(a + b);

Type Annotations

While Zephyr features type inference, types can be explicitly annotated using the : syntax.

let count: int = 0;
fn add(a: int, b: int) -> int {
    return a + b;
}

The any type can be used to bypass static type checking for a specific binding.

let dynamic_val: any = 42;
dynamic_val = "now a string";

Imports & Exports

Zephyr uses a module system where each file is a module.

Imports

import "std/math";                     // default import (all exports)
import "utils" as u;                   // namespace alias
import { sqrt, abs } from "std/math";  // named imports

Exports

export fn greet(name: string) -> void {
    print(f"Hello, {name}!");
}

export struct Point { x: float, y: float }

For more details, see the Modules page.

Literals

Supported literal forms natively tokenized by Zephyr:

• Numbers: 100, 3.14
• Boolean & Null: true, false, nil
• Arrays: [1, 2, 3]
• Format string (f-string): f"hp={value}"