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1 point by almkglor 5747 days ago | link | parent

Okay, I've implemented the continuations idea above. I also tested it a little, and tested a beta version of the arc to bytecode compiler (that's now on the git). Testing revealed a hidden bug in the executors framework ^^ specifically the first bytecode in each function did not get executed. Since the most usual first bytecode is a check of the number of parameters, I didn't see the error ^^

I'm thinking of also implementing the continuations idea above in arc2c.

Edit: Oh, and since we're on the subject of continuations: I don't know, but the lack of a full 'dynamic-wind support in Arc seems rather, err, well, puzzling. What's supported is about half of 'dynamic-wind, i.e. the half that handles exiting the 'dynamic-wind; it's exposed as the ac.scm 'after. This means that if someone creates a generator library and does something like:

  (defgen foo (f)
    (w/infile p f
      (yield (read p))))
... it won't actually work, because once 'yield calls outside of the context of 'w/infile (via a continuation), the file is closed and can't be reopened (because 'w/infile doesn't use an "before" handler, just an "after" handler).

What I'm wondering about is: is this actually OK? If I implement just "after" handlers on continuations, is that "good enough" for Arc?