On Fri, May 29, 2020 at 7:05 PM David Mertz <me...@gnosis.cx> wrote: > On Fri, May 29, 2020 at 3:19 AM Stephen J. Turnbull < > turnbull.stephen...@u.tsukuba.ac.jp> wrote: > >> # Just too ugly for me! >> def foo(x=lambda: random.randint(0,9)): >> >> x = x() >> # ... >> > > I think this is a perfect example of where my desired "delayed" (or > "deferred") construct would be great. There are lots of behaviors that I > have not thought through, and do not specify here. But for example: > > def foo(a=17, b=42,, x=delayed randint(0,9), y=delayed randrange(1,100)): > if something: > # The simple case is realizing a direct delayed > val = concretize x > elif something_else: > # This line creates a call graph, not a computation > z = ((y + 3) * x)**10 > # Still call graph land > w = a / z > # Only now do computation (and decide randoms) > val = concretize w - b >
But if I understand correctly, a delayed value is concretized once, then the value is cached and remains concrete. So if we still have early binding, then x will only have one random value, unlike Stephen's lambda which generates a new value each time it's called.
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