/docs/internals/task_states.txt

 1See task_states.pdf
 2
 3Explanation of states:
 4
 5new:      start not called
 6
 7ready:    task.start()/resume() called. Task is in the 
 8          scheduler q or has been taken out of it and handed to 
 9          the thread. Note that task.running = true (doesn't reflect
10          the 'running' state below)
11          
12running:  stack is resumed. task runs normally to completion
13          or until Task.pause/yield/exit is called.
14
15pausing:  pause called with a PauseReason object
16          pauseReason can be user-defined. Predefined ones are
17          YieldReason, TaskDoneReason, Empty_MsgAvListener, 
18          Full_SpcAvListener etc.
19
20          Task.running remains true until it moves to paused state.
21
22paused:   waiting for a message. 
23          Task.running = false /\ Task.pauseReason.isValid()
24
25done  :   task.execute() returned normally or with an unchecked exception
26          or Task.exit() called
27
28====================================================================
29Messages and task scheduling
30
31What happens when a message arrives in each of the above states?
32
33new: no scheduling on msgs. start() explicitly schedules the task whether
34     or not there are mailboxes.
35
36ready:
37running:   
38    no scheduling necessary when msg is put into mbox; task will rcv
39    the message on get() The distinction between ready and running is
40    not really important from a scheduling or message interaction
41    perspective.
42
43pausing: no scheduling yet, because the task is still unwinding,
44    But after the task is fully unwound, it'll be scheduled again if there
45    are messages in an mbox that caused that task to pause in the first
46    place. 
47
48paused: Schedule the task.
49