Please keep an eye on the www-voice thread. I think there may still be problems with the current step algorithm, and I'm drafting a reply to elaborate on this.
Thanks, Jake On Tue, Mar 1, 2011 at 6:50 PM, Rahul Akolkar <rahul.akol...@gmail.com> wrote: > On Sun, Feb 27, 2011 at 11:51 AM, Jacob Beard <jbea...@cs.mcgill.ca> wrote: >> Hi, >> >> I'm currently working on revising scxml-js so that it implements the >> semantics defined by the step algorithm of the SCXML specification (as >> opposed to the mixture of SCXML semantics and Rhapsody semantics which >> it currently implements). I've run into a part of the step algorithm >> which is somewhat unclear, and because it may relate to a limitation >> in the Commons SCXML implementation, I thought I would ask about this >> on the Commons SCXML list before asking about it on the w3-voice list. >> >> Consider the following SCXML document: >> >> <scxml initial="p"> >> >> <parallel id="p"> >> >> <history id="h"> >> <transition target="A.2 B.2"/> >> </history> >> >> <state id="A" initial="A.1"> >> <state id="A.1"/> >> <state id="A.2"/> >> </state> >> >> <state id="B"> >> <state id="B.1"/> >> <state id="B.2"/> >> </state> >> >> </parallel> >> >> </scxml> >> >> (https://gist.github.com/846316) >> >> >> I believe the step algorithm in the SCXML specification would >> interpret the document in the following way: >> >> addStatesToEnter would at some point be called for parallel state p. >> addStatesToEnter would then be called recursively for each of p's >> children: h, A, B. >> >> addStatesToEnter would first be called for h. Because this is the >> first time h was entered, addStatesToEnter will be recursively called >> for each of the targets of its default transition: A.2 and B.2. A.2 >> and B.2 will then be added to statesToEnter. >> >> addStatesToEnter would then be called for state A. A is a compound >> state, so addStatesToEnter would then be called for A's initial state: >> A.1. A.1 would then be added to statesToEnter. >> >> The same would occur for B, and so B.1 would be added to statesToEnter. >> >> The resulting configuration would then be: p,h,A,B,A.1,A.2,B.1,B.2, >> which is not a legal configuration, as A and B are both OR states. >> >> >> >> Is my interpretation of the specification correct, in that the step >> algorithm would allow this illegal configuration, or am I missing >> something? >> >> >> >> I'm asking this question here, rather than on the w3-voice list, >> because I believe Commons SCXML does not currently support history in >> parallel: >> http://mail-archives.apache.org/mod_mbox/commons-user/201001.mbox/%3cce1f2ea81001131340w2aaaf5bfs84b9db2252287...@mail.gmail.com%3E >> >> It's not clear whether this is due to possible conflicts in SCXML >> semantics, or whether this is simply Commons SCXML implementation >> lagging a bit behind changes in the specification. >> > <snip/> > > Its lag. I believe you have your answer on w3-voice, if not, let me > know and I'll look further. > > -Rahul > > >> I'd appreciate any guidance you can offer. Thanks, >> >> Jake >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org > For additional commands, e-mail: dev-h...@commons.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@commons.apache.org For additional commands, e-mail: dev-h...@commons.apache.org
