As far as I recall, REPLY can't be used unless there's some kind of :: directive in a program (at the bottom!). Always thought that was an unnecessary restriction. Mike
_____ From: Jean-Louis Faucher [mailto:jfaucher...@gmail.com] Sent: 05 June 2011 18:49 To: Open Object Rexx Developer Mailing List Subject: Re: [Oorexx-devel] Reply in routines, possible ? (Re: Reply in native method ? Hi Rony 2011/6/5 Rony G. Flatscher <rony.flatsc...@wu-wien.ac.at> would it be possible to have the REPLY keyword statement for routines? If I remove the test context->inMethod() then reply *seems* to work from a ::routine (tested with a tiny script). But this is not a proof that it would work all the times. It crashes when called from an internal routine. There are quite a few cases, where using routines and multithreading would seem to be easier to comprehend and to apply, if REPLY was available for routines. A good old class method is almost as simple as a ::routine. I don't see any gain of functionality if we allow to reply from a ::routine, unless we allow also to expose some variables from a ::routine. [digression] Instructions that can be called only from methods : expose : I still don't understand why it's not possible to expose variables from a ::routine... If we do a relation with - anonymous inline functions (often called lambda or block), - outer environment (the variables used by the lambda, which are not parameters), - and closure (which is the outer environment which remains associated to the lambda, even when the lambda is called outside the definer's scope), then the exposed variables would be the variables to retain in the closure. Most of the languages don't require to declare the variables to capture, but C++ lets optionally declare them, and that remind me the functionality of our expose : ----- c++ std::vector<int> some_list; int total = 0; std::for_each(some_list.begin(), some_list.end(), [&total](int x) { total += x; }); ----- oorexx (with extensions) some_list = .array~of.. total = 0 some_list~each([expose total; total += arg(1)]) ----- C++ lets capture a variable by value or by reference. In ooRexx, expose is always by reference, right ? Currently, only internal procedures allow to expose variables, but internal procedures can't be manipulated like routines... In the example above, there is a need of closure, because the lambda is called in the context of the 'each' method, which is not the context of the definer (i.e. 'each' does not - and could not - expose the 'total' variable). forward : nothing to say guard : in relation with the object variables dictionary (ovd). I don't know if the routines have a similar concept like caller variables dictionary (cvd ?). And I don't know if that would make sense to manage synchronisation on this cvd. Probably yes, synchronisation would be necessary if we allow - reply and expose in ::routine - expose and closure (even if no reply in ::routine, because thanks to the closure, a routine can be passed as argument to methods which reply, and then call the routine which will access to the exposed variable of the closure). reply : already discussed Jean-Louis
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