Hello again, Chris,

your example is not that bad; your only mistake is that you signal
a foreign monitor without entering its critical region.

You have to replace     goalMonitor signal.
with:   goalMonitor critical: [goalMonitor signal].

and in the same way

  fives signal.   with:    fives critical: [fives signal].
 nonFives signal.  with:  nonFives critical: [nonFives signal].

The following works:

     | goal work fives nonFives counter goalReached goalMonitor |
     goal _ (1 to: 1000) asOrderedCollection.
     work _ OrderedCollection new.
     fives _ Monitor new.
     nonFives _ Monitor new.
     counter _ 0.
     goalReached _ false.
     goalMonitor _ Monitor new.

     [ fives critical:
         [ [ fives waitUntil: [ counter \\ 5 = 0 ].
         goalReached or:
             [ work add: (counter _ counter+1).
             nonFives critical: [nonFives signal].
             goalReached _ counter >= goal size ] ] whileFalse.
         goalMonitor critical: [goalMonitor signal] ] ] fork.

     [ nonFives critical:
         [ [ nonFives waitWhile: [ counter \\ 5 = 0 ].
         goalReached or:
             [ work add: (counter _ counter+1).
             fives critical: [fives signal].
             goalReached _ counter >= goal size ] ] whileFalse.
         goalMonitor critical: [goalMonitor signal] ] ] fork.

     goalMonitor critical:
         [ goalMonitor waitUntil: [ goalReached ].
        ].

  work = goal


-----------------------

Note that the process 'fives' adds the seqeuence 1, 6, 11 into your
collection. To fix that, both processes should use the wait condition
 [ counter \\5 = 4].
Alternatively, the counter could start at 1 and be incremented after
insertion into the collection. The correct expression for  goalReached
would then be:  counter > goal size.


Greetings, Boris