Bug 150290 – [ES6] Implement Generators

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Yusuke Suzuki]

Implement ES6 generators.
Consider the following case,

let generator = gen();
// first example.
for (let value of generator) {
    ...
}

function* gen() {
    // (1).
    ...
    // (2).
    yield;
}

in for-of, we call generator.next(). In the first case, it starts from (1). And the second call starts from (2).
So I think generating the following code for ES6 generator is the easiest way to handle it in DFG / FTL. How about this?

// Entry point is only one. Every time we call generator.next(), the function will start from here.
resume_to_yield (generator_object)  // This resumes frame and jump.
label_1:
// (1).
special_return;
label_2:
// (2).
special_return;

[Yusuke Suzuki]

Working on syntax part at first...