Syntax Basics, Comments and Style

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3.1 Program Structure

Statements end with ;. Blocks use {}. Indentation is 4 spaces (zig fmt enforces the canonical style).

Order-independent top-level declarations: functions and constants can be used before they're defined.

Every file is a struct. Top-level declarations are the struct's members.

const std = @import("std");          // import the standard library
const math = std.math;               // alias a namespace

const max_users = 100;               // top-level constant (container-level declaration)

pub fn main() void {                 // `pub` = visible to other files
    const x: i32 = 5;
    std.debug.print("{d}\n", .{x});
}

3.2 Comments

There are no multi-line comments in Zig. This is deliberate: each line can be tokenized independently.

// Normal comment

/// Doc comment for the following declaration (shows up in generated docs)
pub fn add(a: i32, b: i32) i32 {
    return a + b;
}

//! Top-level doc comment (describes the current module/file); must be at the start of the file

3.3 Identifiers and Naming Style

Types (structs, enums, unions, type-returning functions) ArrayList, Point readFile, parseInt

Variables, constants, fields, parameters max_len, user_id Files that are types (have fields) Files that are namespaces

@"any identifier" syntax allows otherwise invalid names (keywords, C symbols): const @"type" = 5;.

3.4 Keywords

3.5 Unused Variables Are Errors

Unused locals, parameters, and imports are compile errors. Discard explicitly with _ = value;.

Unused function results are also errors unless discarded: _ = compute();.