#Methods

func greet(name as string) {
    io.printf("hello, %s\n", $name);
}

greet("Jennifer");   # call it from top level

Two keywords, two jobs:

• def [const] NAME ... introduces a binding (variable or constant).
• func NAME(p as TYPE, q as TYPE) { ... } introduces a method.

Parameters use bare identifiers (same rule as def) and each has a declared type. Inside the body, parameters are referenced as $p like any other variable. At the call site, the interpreter checks the number of arguments and the kind of each one - mismatches produce a positioned error.

Return values use return EXPR; to return a value or return; to return null. A body that runs to the end without return also yields null. Methods don't declare a return type; the caller's type check (e.g. def x as int init mymethod();) is what enforces the value's kind at the use site.

Recursion works out of the box - methods are hoisted, so any method can call any other (or itself) by name.

func fact(n as int) {
    if ($n == 0) { return 1; }
    return $n * fact($n - 1);
}

io.printf("%d\n", fact(5));    # 120

Methods are hoisted: all func NAME() { ... } declarations are collected before any top-level statement runs, so a method can be called from anywhere in the file regardless of where it's defined. There is no required entry point - top-level statements execute in source order.

Methods can only be defined at the top level (not inside another method's body). Method bodies inherit the global scope, so top-level variables are visible inside methods (subject to the no-shadowing rule).

Methods cannot shadow imported builtins. If you write use io; and then func io.printf() { ... }, the program is rejected:

runtime error at 2:1: method "printf" shadows a builtin from `io`;
rename it or remove `use io;`

Without the use io;, the name is yours to define. This is the same no-shadowing discipline Jennifer applies to variables.

#Methods as values

A method name is also a function value: written bare (no (), it evaluates to a func you can store, pass, and call later - def f as func init greet; then $f(args). This is what powers the higher-order lists helpers (lists.map / filter / reduce / ...). See Function values for the full rules.