RE: the default initial state for a <parallel> state doesn't make sense

Good point,  I'll correct it.
- Jim

-----Original Message-----
From: Gavin Kistner [mailto:[email protected]] 
Sent: Monday, May 13, 2013 11:14 AM
To: Jim Barnett
Cc: [email protected]; [email protected]
Subject: Re: the default initial state for a <parallel> state doesn't make sense

FWIW I was confused by section 3.3.2 repeatedly. I understand now that a parallel is not a "compound state", but it is a "state" (but not a <state>) that has the children mentioned in 3.3.2.

Despite section 3.3.2 being part of 3.3, referring to <state>, it might help if the definition were tweaked to say:

"A compound state is a <state> that has …"

--
(-, /\ \/ / /\/ (via phone)

On May 13, 2013, at 8:43 AM, Jim Barnett <[email protected]> wrote:

> I read the specification differently.  Section 3.3.2 says a compound <state> is one that has <state>, <parallel> or <final> children.  This doesn't say anything about <parallel> states.  They are never compound states and thus do not have a default initial state.  Sections 3.1.4 and 3.3.2 refer to the <state> element only.
> 
> - Jim
> 
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] 
> Sent: Monday, May 13, 2013 9:31 AM
> To: [email protected]
> Subject: the default initial state for a <parallel> state doesn't make sense
> 
> Hello,
> 
> I can read in section 3.1.4 [1]:
> "If neither the <initial> child or the 'initial' element is specified, the default initial state is the first child state in document order." (speaking about the default initial state of a compound state).
> 
> And I can read in section 3.3.2 [2]:
> "Definition: A compound state is one that has <state>, <parallel>, or <final> children (or a combination of these)"
> 
> So, a <parallel> state without <initial> child or 'initial' element specified, will have a default initial state (the first child state in document order).
> 
> In the case of the parallel Microwave [3], the default initial state will be the "engine" state because it is the first child in document order for the "oven" <parallel> compound state.
> 
> That doesn't make sense for me because a <parallel> state shouldn't have a default initial state.
> The semantics of a <parallel> state is a AND of its children state.
> So, there is no initial state at all.
> 
> I suggest to apply the default initial state only on <state> that are compound state.
> 
> What you think about this ?
> 
> Thank you.
> Regards.
> 
> [1] http://www.w3.org/TR/scxml/#CoreIntroduction
> [2] http://www.w3.org/TR/scxml/#state
> [3] http://www.w3.org/TR/scxml/#MicrowaveParallel
>