On Apr 24, 2005, at 11:57 PM, Phillip J. Eby wrote:
At 11:39 PM 4/24/05 -0400, Bob Ippolito wrote:
On Apr 24, 2005, at 11:32 PM, Phillip J. Eby wrote:
At 04:57 PM 4/24/05 -0700, Guido van Rossum wrote:So a block could return a value to the generator using a return statement; the generator can catch this by catching ReturnFlow. (Syntactic sugar could be "VAR = yield ..." like in Ruby.)
[uncontrolled drooling, followed by much rejoicing]
If this were available to generators in general, you could untwist Twisted. I'm basically simulating this sort of exception/value passing in peak.events to do exactly that, except I have to do:
yield somethingBlocking(); result=events.resume()
where events.resume() magically receives a value or exception from outside the generator and either returns or raises it. If next()-with-argument and next_ex() are available normally on generators, this would allow you to simulate co-routines without the events.resume() magic; the above would simply read:
result = yield somethingBlocking()
The rest of the peak.events coroutine simulation would remain around to manage the generator stack and scheduling, but the syntax would be cleaner and the operation of it entirely unmagical.
Only if "result = yield somethingBlocking()" could also raise an exception.
Read Guido's post again; he proposed that passing a result would occur by raising a ReturnFlow exception! In other words, it's the result passing that's the exceptional exception, while returning an exception is unexceptional. :)
Oh, right. Too much cold medicine tonight I guess :)
You're right, of course. This facility would be VERY nice to ab^Wuse when writing any event driven software.. not just Twisted.
-bob
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