Remark about SCXML "entry set" definition (section 3.11)

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Remark about SCXML "entry set" definition (section 3.11)

Ate Douma
(I send this same email on March 4th, but never seem to have gotten through)

Hi there,

After reading the current SCXML spec, I find the definition of "entry set"
confusing, possible incorrect.

In section 3.11, for [Definition: The entry set ...] the following is stated:

   [...] Otherwise, it consists of all members of the transition's complete
target set that are not currently active. [..]

Maybe I'm missing something obvious here, but it seem to me this can't be
correct. Why are only 'not currently active' states considered?
A currently active state can be both exited and (re)entered as result of a
single transition, so should (and IMO is to) be included in the entry set as well.

The "computeEntrySet" procedure in appendix A also doesn't reflect this AFAICT,
only determining the entry set based on the transition targets only, not the (at
that time already exited) current active states

Thanks,

Ate

(working on Apache Commons SCXML 2.0 towards spec compliance)


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Re: Remark about SCXML "entry set" definition (section 3.11)

Jim Barnett
Ate,
  You are right.  In the current public draft there is a conflict between the text and the algorithm, and the algorithm is correct and the text is incorrect.  I propose expanding the definition of entry set as follows, so that it will match the algorithm:

"[Definition: The entry set of a transition in configuration C is the set of states that are entered when the transition is taken. If a transition does not contain a 'target', its entry set is empty. Otherwise, it consists of all members of the transition's complete target set that that are not currently active or are in the exit set. (Thus the entry set consists of all members of the transition's complete target set that will not be active once the states in the exit set have been exited.) The entry set of a set of transitions is the union of the entry sets of the individual transitions.]"

(By the way, the correct section number is 3.13, not 3.11.) 

Please let me know if you are satisfied with this response.  If we do not hear from you by March 24th, we will assume that you are. 

Best,
Jim Barnett

On 3/7/2014 6:57 AM, Ate Douma wrote:
(I send this same email on March 4th, but never seem to have gotten through)

Hi there,

After reading the current SCXML spec, I find the definition of "entry set" confusing, possible incorrect.

In section 3.11, for [Definition: The entry set ...] the following is stated:

  [...] Otherwise, it consists of all members of the transition's complete target set that are not currently active. [..]

Maybe I'm missing something obvious here, but it seem to me this can't be correct. Why are only 'not currently active' states considered?
A currently active state can be both exited and (re)entered as result of a single transition, so should (and IMO is to) be included in the entry set as well.

The "computeEntrySet" procedure in appendix A also doesn't reflect this AFAICT, only determining the entry set based on the transition targets only, not the (at that time already exited) current active states

Thanks,

Ate

(working on Apache Commons SCXML 2.0 towards spec compliance)



--
Jim Barnett
Genesys
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Re: Remark about SCXML "entry set" definition (section 3.11)

Ate Douma
Hi Jim,

On 09-03-14 21:33, Jim Barnett wrote:

> Ate,
>    You are right.  In the current public draft there is a conflict between the
> text and the algorithm, and the algorithm is correct and the text is incorrect.
> I propose expanding the definition of entry set as follows, so that it will
> match the algorithm:
>
> "[Definition: The /entry set/ of a transition in configuration C is the set of
> states that are entered when the transition is taken. If a transition does not
> contain a 'target', its entry set is empty. Otherwise, it consists of all
> members of the transition's complete target set that that are not currently
> active or are in the exit set. (Thus the entry set consists of all members of
> the transition's complete target set that will not be active once the states in
> the exit set have been exited.) The entry set of a set of transitions is the
> union of the entry sets of the individual transitions.]"
>
> (By the way, the correct section number is 3.13, not 3.11.)
Sorry about that :)

>
> Please let me know if you are satisfied with this response.  If we do not hear
> from you by March 24th, we will assume that you are.

Yes, I agree with the above update of the definition.

Thanks,
Ate Douma

>
> Best,
> Jim Barnett
>
> On 3/7/2014 6:57 AM, Ate Douma wrote:
>> (I send this same email on March 4th, but never seem to have gotten through)
>>
>> Hi there,
>>
>> After reading the current SCXML spec, I find the definition of "entry set"
>> confusing, possible incorrect.
>>
>> In section 3.11, for [Definition: The entry set ...] the following is stated:
>>
>>   [...] Otherwise, it consists of all members of the transition's complete
>> target set that are not currently active. [..]
>>
>> Maybe I'm missing something obvious here, but it seem to me this can't be
>> correct. Why are only 'not currently active' states considered?
>> A currently active state can be both exited and (re)entered as result of a
>> single transition, so should (and IMO is to) be included in the entry set as
>> well.
>>
>> The "computeEntrySet" procedure in appendix A also doesn't reflect this
>> AFAICT, only determining the entry set based on the transition targets only,
>> not the (at that time already exited) current active states
>>
>> Thanks,
>>
>> Ate
>>
>> (working on Apache Commons SCXML 2.0 towards spec compliance)
>>
>>
>
> --
> Jim Barnett
> Genesys