Language Reference

Functions, Calls, and Function Values

Function declarations, explicit multi-argument calls, the single-argument bare-call form, and first-class function values.

Function declaration

function add(left: i64, right: i64) -> i64 {
    return left + right;
}

let answer = add(20, 22);

Function declarations define a name, typed parameters, a return type, and a body. Standard calls use parentheses and commas for arguments.

Call syntax

The current parser accepts a compact bare-call form when a single argument is supplied:

use std.io;

print("parentheses-call");
print "bare-call";

This shorthand is intentionally narrow. Multiple arguments should use parenthesized syntax:

let value = add(20, 22);

Function values are not automatic calls

A function name used as a value refers to that function; it does not invoke it automatically. This supports callback-style use while keeping the call site explicit.

function meaning() -> i64 {
    return 42;
}

let value = meaning;
let answer = value();
let direct = meaning();

Here, value holds a function value. Both value() and meaning() explicitly call a function; meaning without parentheses does not.

Current limitations

• The function-value type form is represented as Fn(Args)->Return, but capture and closure semantics are not defined.
• A bare name does not implicitly invoke the referenced function.
• The accepted argument grammar for bare calls should remain documented as a specific shorthand rather than a general replacement for call parentheses.