Functions

Functions are the primary unit of execution in Mist. They prioritize a traditional declaration order, placing the return type before the identifier to ensure signatures remain easy to scan in complex systems.

Basic Syntax

A standard function requires a return type, a name, and a body. Use the void keyword for functions that do not return a value.

i32 add(i32 a, i32 b) {
    return a + b;
}

void log_status(str* message) {
    println!("{}", message);
}

Visibility & Exports

Functions are private to their module by default. The public modifier exports the function for cross-module access.

public i32 get_version() {
    return 1;
}

Mutable Parameters

Parameters follow Rust’s ownership rules but use Mist’s local variable syntax. Use mut to allow a function to modify its local binding of a value.

void update_score(i32 mut current_score, i32 bonus) {
    current_score = current_score + bonus;
}

Generics & Lifetimes

Mist integrates type abstraction and memory management into a single generic block. Lifetimes and type parameters share the < > bracket following the identifier.

public str'a* choose_longer<'a, T: Display>(str'a* s1, str'a* s2, T meta) {
    println!("Metadata: {}", meta);
    return if (s1.len() > s2.len()) { s1 } else { s2 };
}

Attributes & Metadata

Metadata is applied via the #[attr] syntax directly above the declaration for compiler hints or testing.

#[inline]
public bool is_active(u32 id) {
    return id > 0;
}

Key Characteristics

• Scannable Signatures: Placing return types first allows for rapid identification of a function's output.
• Unified Abstraction: Lifetimes and type constraints are declared in one location, reducing signature noise.
• Zero-Cost Mapping: Every function maps directly to a Rust fn, maintaining performance and ecosystem compatibility.