On 7/10/07, Ken Manheimer <[EMAIL PROTECTED]> wrote:
the elementary structures by which computations can be stored for later continuation are called just that - continuations. closures, on the other hand, are an organization of program state that can be associated with an object - typically to implement static scoping, as was done for python functions and methods around, someone said, python 2.1. i seem to recall that ruby manifests blocks as first class objects, and associates closures with them, as well.
Ugg! Hey Curt, we're now twins! ;-) Yep, I most definitely confused things here. Thanks for the correction! (continuations are interesting, but mostly in the abstract - they're not
generally of interest for direct use by programmers. they're the mother of all control flow structures - all the others can be expressed and built using them, but they're very low-level - you would hardly ever want to program with them directly. stackless python uses (used?) them as a key means of building the other flow control structures without using the machine (c, in that case) stack, and they enable economies for massive parallelism that most of us don't need (and couldn't handle without major attention). generators provide the means to express much of what programmers practically want in this vein, and the recent refinements to enable use of generators as coroutines (pep 342<http://www.python.org/dev/peps/pep-0342/>) covers most of the rest. how these structures map to parallelism are up to the language implementation. guido has been actively disinterested in incorporating continuations to the python definition, for various reasons, and i don't expect that to change.)
Yep. this all makes sense. i couldn't resist this clarification, and hope i haven't mistaken what you
were saying (or, what i'm saying:-).
Nope, you are right on the money. I said closures, but meant continuations. Thanks for correcting me! -- /M:D M. David Peterson http://mdavid.name | http://www.oreillynet.com/pub/au/2354 | http://dev.aol.com/blog/3155
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