On Wed, Oct 20, 2021 at 8:44 PM Henrik Grubbström (Lysator) @ Pike (-)
developers forum <[email protected]> wrote:
> Not quite correct; normal ones are 0..USHRT_MAX-1 and builtin
> functions are USHRT_MAX. The subtype is used to select the
> function entry in the function table for the object.
Ahh gotcha.
> AFAIR the generator function gets the suffix "\0generator" appended
> to its function name, but I'm uncertain whether this is visible at
> the Pike code level.
It technically is, if you sprintf("%O", f), but that seems a hacky way
to recognize generator state functions. It also doesn't recognize
generator functions themselves, although that's less important.
> There may also be a difference in the value returned by _typeof().
True in a sense, when looking at a specific generator and its state
function, but I don't think this can be used to directly recognize
them:
fibonacci: /main()->fibonacci function( : function(void | mixed, void
| function(void | mixed ... : void) : int | zero))
fib: /main()->fibonacci\u0000generator function(void | mixed, void |
function(void | mixed ... : void) : int | zero)
The use-case is an asynchronous function handler. I've started to
write it up here:
https://rosuav.github.io/StilleBot/Asynchronicity#asynchronous-functions-with-yield-points
The spawn_task callable needs to be able to recognize a
Concurrent.Future or a generator state function as things to await,
and anything else as things to return.
If I could ask for the moon here, I'd also really love to be able to
know when a state function has finished, other than calling it again
and getting undefined back. That would allow a simple check after
getting a value to determine whether the value was yielded or
returned: if the state function is now finished, then it was returned,
otherwise it was yielded (and we should go back and do more stuff
later). At the moment, I have to assume that there's still more to do,
and then if I ever get an undefined, I assume that the function is
finished. That could conceal bugs.
I've been tinkering with trying to create a Function.function_type()
function, but so far, it's looking like most of the information is
handled at compilation time only.
ChrisA
