JS Iterators, generators, and destructuring · Pull Request #275 · pierrelf.com/we

Implements issue 3mhn3peabad2h

Summary #

Generator functions: function*, yield, yield*, generator.next(value), generator.return(value), generator.throw(error)
Iterator protocol: Symbol.iterator (@@iterator), for...of loops using the iterator protocol
Built-in iterators: Array.prototype[@@iterator], String.prototype[@@iterator], Map.prototype[@@iterator], Set.prototype[@@iterator], plus keys()/values()/entries() returning proper iterators
Destructuring fixes: Fixed register allocation LIFO violations, added rest elements for both array ([a, ...rest]) and object ({a, ...rest}) destructuring
Spread operator: [...arr] in array literals using the iterator protocol
Bytecode: Added Yield and Spread opcodes, is_generator flag on Function
25 new tests covering generators, for...of, destructuring, spread, and custom iterables

All 495 JS unit tests pass. Clippy clean. Formatted.