evan_tech -- reading

04:19 pm, 9 Feb 04

reading

Reading project: Ken Shan's continuations reading group. The 5th background paper uses C analogies, which is weird. Apparently this is a GNU C extension:

void p(void *x) {
    goto *x;  /* weird: dereferencing void* */
}
main() {
    p(&&L1);  /* weird: double-& operator. */
L1: exit();
}

It makes sense, though.

xaosenkosmos That is one of the ugliest things i have ever seen.

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mspin ewwwww
Nifty:)

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zezu this is one of those 'letter of the law' bleeding edge cases which would die enflambé during a decent code review.

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jeffr	I considered using this for some things in cogs, and then I realized how horrible it is and gave up. I think gcc calls it a non local goto. You can also do equally horrible things like intercept function calls whose prototypes you don't know and reconstruct arguments for function calls manually. You can almost make c a dynamic binding language.
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billemon

Re:

… like intercept function calls whose prototypes you don't know and reconstruct arguments for function calls manually.

Almost, but the gcc manual on my inspection seems not to tell you how to calculate the size of the arguments on the stack :( Shame.

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billemon	This is something I've been struggling a bit to understand. A continuation in other languages is like the non-local goto but you can use it after the calling function has returned, isn't it?
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evan	Re: The page I linked to has a collection of background reading. Read it! :) But yeah, your intuition is pretty much correct, but they're much more general and powerful than that.
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xaosenkosmos	That is one of the ugliest things i have ever seen.
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zezu	this is one of those 'letter of the law' bleeding edge cases which would die enflambé during a decent code review.
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mspin	ewwwww Nifty:)
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