User-Defined Functions

Feature	Status	Description
Single-line f(x) => expr	✅	Arrow function
Multi-line block body	✅	Indented block
Default parameters	✅	f(src, int len = 14)
Named arguments	✅	f(length = 20, src = close)
Nested function calls	✅	User functions calling user functions
var/varip in functions	✅	Persistent state inside functions
Recursion guard	✅	Max depth 50
method keyword	✅	Parsed as function def with isMethod
export keyword	✅	Skipped (no library support)