> So, the setup is a group of three coroutines, with the execution
> threaded through them. The original invocation prints 1 and creates
> the second one. The second one prints 1 and switches back to the
> first. The first prints 2 and creates a third invocation, which prints
> 1 and jumps back to the first. The first prints 3 and completes. This
> is how "11213" is produced.

this made my day :) I just had to swap two statements in the 
implementation of 'let for my scheme to comply with the Mondo Bizarro 
puzzle.

now I wonder how many similar traps are still open in my code... looks 
like I can expect 'call/cc to to behave badly again some time, since I 
don't see a way to get a systematic overview of these subtle issues and 
fix them all.

what I can do is implement a call/cc stress test for my scheme. if 
people have little nasty piece of scheme code to submit, I would gladly 
include them in the test suite.

for those interested, the scheme for Squeak is available here:
http://www.zogotounga.net/comp/squeak/lispkit.htm

and the current tests are the #testCallCC serie in ULispWithLibTest. 
obviously I need more or them.


regards,

Stef