Generators

[alongubkin]

Add generators support to Spider.

fn inorder(node) {
  if (node) {
    yield* inorder(node.left);
    yield t.label;
    yield* inorder(node.right);
  }
}

compiles to:

function* inorder(node) {
  if (node) {
    yield* inorder(node.left);
    yield node.label;
    yield* inorder(node.right);
  }
}

Note that * is not required near the Spider function declaration.

If you have a better idea for the yield* syntax, please let me know.

[Namek]

Seeing this I dream about having lazy evaluation (for variables).

[nmn]

This would be a big big win. Also, considering the fact that Spider already supports async functions, its surprising that generators aren't supported yet.

[Deveritas]

 If you have a better idea for the yield* syntax, please let me know.

Some possible keyword ideas: delegate, enter, use...
Of course, this is completely leaving out the question of whether a keyword is better than syntax in this case.

[nmn]

I think the yield* syntax is fine. It makes sense, and is consistent.
Also, there is no obvious better syntax here...