Summary:
This diff adds a new way of executing blocks when they are passed as parameters to a method. So far we just skipped the block in this case.
Now we can execute it. Let's demonstrate with an example. Say we have
//foo has a block parameter that it executes in its body
foo (Block block) { block();}
// bar calls foo with a concrete block
bar() {
foo (^(){
self->x = 10;
});
};
Now, when we call the method foo with a concrete block, we create a copy of foo instantiated with the concrete block, which in itself is translated as a method with a made-up name.
The copy of foo will get a name that is foo extended with the name of the block parameter, the call to the block parameter will be replaced to a call to the concrete block, and the captured variables
of the concrete block (self in this case), will be added to the formals of the specialized method foo_block_name.
This is turned on at the moment for ObjC methods with ObjC blocks as parameters, and called with concrete blocks. Later on we can extend it to other types of methods, and to C++ lambdas, that are handled similarly to blocks.
Another extension is to check when the block has been called with nil instead of an actual block, and raise an error in that case.
After this diff, we can also model various methods and functions from the standard library that take blocks as parameters, and remove frontend hacks to deal with that.
Reviewed By: ddino
Differential Revision: D6260792
fbshipit-source-id: 0b6f22e
Jeremy Dubreil
Dulma Churchill