Try this... slightly more complex but get's the job done-> added some
wait state in the user program/thread so it didn't kill the output
stream... Enjoy
import thread, sys, time
def someUserProgram(mutexRef):
while 1:
mutexRef.acquire()
print "I am a user program"
mutexRef.release()
time.sleep(1)
class main:
def __init__(self):
self.mutex = thread.allocate_lock()
self.someProgram = None
def mainProgram(self,someUserProgram):
self.someProgram = someUserProgram
self.executeOneStatement(self.someProgram)
inval = ''
while not inval == 'q':
inval = sys.stdin.readline().strip()
print "Doing some stuff here"
thread.exit()
def executeOneStatement(self,program):
thread.start_new(program, (self.mutex,))
l = main()
l.mainProgram(someUserProgram)
Justin Powell wrote:
> Hi, I'm looking for suggestions on how to accomplish something in python. If
> this is the wrong list for such things, I appologize and please disregard the
> rest.
>
> My application needs to allow users to create scripts which will be executed
> in a statement-by-statement fashion. Here's a little pseudo-code:
>
> def someUserProgram():
> while 1:
> print "I am a user program"
>
> def mainProgram():
> someProgram = someUserProgram
> while 1:
> print "Doing some stuff here"
> executeOneStatement(someProgram)
>
> def executeOneStatement(program):
> # What goes in here?
>
> I would expect the output to look like this:
>
> Doing some stuff here
> Doing some stuff here
> I am a sub program
> Doing some stuff here
> Doing some stuff here
> I am a sub program
> etc.
>
> It's possible to use generators to accomplish this, but unfortunately a
> state-ment by statement executing would require that every other statement is
> a yield. That would either force the users to put in a yield after every
> statement, or require a mechanism that parses the source and inserts yield
> statement before execution. Neither of these are really satisfactory
>
> The other methods I've considered for doing this cleanly (subclassing the
> debugger, or the interactive interpreter) seem to revolve around sys.settrace
> and a callback trace function. I couldn't figure out a way to use this
> mechanism to resume the main loop from the trace function, and then also
> resume the user program the next time around, without the call stack just
> spiraling out of control.
>
> Anybody have a solution to this? I've done a bit of searching, looking
> through python docs and sources and so forth, and I'm pretty stumped at this
> point.
>
> Thanks.
>
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