Constants

Declaration

<constant_declaration> ::= "const" <ident> [<type_signature>] ;

Dependencies:

• <ident>
• <type_signature>

The <constant_declaration> is a "const" followed by an identifier and optional type signature.

Assignment

<constant_assignment> ::=
    <constant_declaration> "=" <expr> ;

Dependencies:

• <expr>

The <constant_assignment> is a constant declaration followed by an assignment operator and either an expression or a comma separated list of identifiers delimited by parentheses followed by a code block.

Semantics

Constants must be resolvable at compile time either by assigning it a literal, another constant, or an expression that can be resolved at compile time.

The type of a constant will only be inferred if its assignment is a literal with a type annotation, another constant with a resolved type, or an expression with a resolved type such as a function call.

const A: u8 = 1;
const B = 1u8;
const C = B;
const D = a();
const E: u8 = b();

comptime fn a() -> u8 {
    1
}

fn b() -> T {
    2
}