Module Declarations

Every Mana source file must begin with a module declaration. This tells the compiler what module the file's contents belong to.

Basic Module Declaration

module myapp
 
fn main() -> void {
    println("Hello from myapp!")
}

The module name typically matches the file name or represents the logical grouping of the code.

The Main Module

For executable programs, use module main:

module main
 
fn main() -> void {
    println("Program starting...")
}

The main module is special—it's the entry point for your program and must contain a main() function.

Library Modules

For reusable code, use a descriptive module name:

// math.mana
module math
 
pub fn add(a: int, b: int) -> int {
    return a + b
}
 
pub fn multiply(a: int, b: int) -> int {
    return a * b
}

Submodules

Use dot notation for hierarchical modules:

// utils/strings.mana
module utils.strings
 
pub fn trim(s: string) -> string {
    return s.trim()
}
 
pub fn uppercase(s: string) -> string {
    return s.to_upper()
}

// utils/numbers.mana
module utils.numbers
 
pub fn abs(n: int) -> int {
    if n < 0 {
        return -n
    }
    return n
}

Module Naming Conventions

• Use lowercase names: module graphics
• Use dots for hierarchy: module graphics.sprites
• Match the file path: src/utils/math.mana → module utils.math

File Structure

A typical project structure:

my_project/
├── mana.toml
├── src/
│   ├── main.mana          # module main
│   ├── game.mana          # module game
│   └── utils/
│       ├── math.mana      # module utils.math
│       └── strings.mana   # module utils.strings
└── build/

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