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Re: Tricky!

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On 7/30/2019 11:03 AM, Tim Rentsch wrote:
> That depends on what is meant by "practical".  It can be done
> like this:
> 
>      #include <iostream>
> 
>      class State {
> 	using Nexter = ...;
> 
>        public:
> 	State(){}
> 	Nexter r0(){  return  &State::r1;  }
> 	Nexter r1(){  return  &State::r2;  }
> 	Nexter r2(){  return  &State::rn;  }
> 	Nexter rn(){  return  0;  }
>      };
> 
>      void
>      run_state_machine(){
> 	State *s = new State;
> 
> 	for(  auto f = &State::r0;  f;  f = (s->*f)()  ){
> 	    ::std::cout << "Got one\n";
> 	}
>      }


A better solution might be a state machine that can iterate N
times setup at instantiation, and then optionally reset when
exhausted so it can be re-entered the second time (untested,
but generally speaking this concept should work):


     #include <iostream>

     class State
     {
         using Nexter = ...;

     public:
         State(int nStateCount)
         {
             nState_    = -1;
             nStateMax_ = max(1, nStateCount);
         }

         Nexter next(bool lReset = false)
         {
             if (++nState < nStateMax)
                 return &this->next;  // Return self

             // When we get here, we're done with this state traversal
             if (lReset)
                 nState = -1;  // Prepare for the next one

             // Indicate this state is exhausted
             return null;
         }

         void reset(int nState = -1)
         {
             nState_ = max(-1, min(nState, nStateMax));
         }

         int state(void) { return nState_; }
         int max(void)   { return nStateMax_; }

     private:
         int  nState_;
         int  nStateMax_;
     };

     void run_state_machine()
     {
         State* s = new State(4);
         ...

-- 
Rick C. Hodgin

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Tricky! Bonita Montero <Bonita.Montero@gmail.com> - 2019-07-29 13:49 +0200
  Re: Tricky! Öö Tiib <ootiib@hot.ee> - 2019-07-29 06:30 -0700
    Re: Tricky! "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-07-29 17:59 +0200
      Re: Tricky! Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-07-30 08:03 -0700
        Re: Tricky! "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2019-07-30 11:20 -0400
        Re: Tricky! "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-07-30 18:00 +0200
          Re: Tricky! Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-10 14:19 -0700
    Re: Tricky! Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-07-30 07:31 -0700
      Re: Tricky! Öö Tiib <ootiib@hot.ee> - 2019-07-30 09:22 -0700
        Re: Tricky! Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-10 14:45 -0700
          Re: Tricky! Öö Tiib <ootiib@hot.ee> - 2019-08-11 03:23 -0700
            Re: Tricky! Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-17 22:02 -0700
              Re: Tricky! Öö Tiib <ootiib@hot.ee> - 2019-08-17 23:53 -0700
                Re: Tricky! Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-18 05:22 -0700
  Re: Tricky! Sam <sam@email-scan.com> - 2019-07-29 20:51 -0400
  Re: Tricky! Sam <sam@email-scan.com> - 2019-07-29 20:52 -0400
  Re: Tricky! Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-07-30 13:58 +0100
    Re: Tricky! Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-11 09:06 +0200

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