source: doc/papers/concurrency/examples/ProdCons.cfa @ 9cd5bd2

#include <fstream.hfa>
#include <coroutine.hfa>
#include <stdlib.hfa>                                                                   // random
#include <unistd.h>                                                                             // getpid
coroutine Cons;                                                                                 // forward
int delivery( Cons & cons, int p1, int p2 );
void stop( Cons & cons );

coroutine Prod {
        Cons & c;
        int N, money, receipt;
};
void main( Prod & prod ) with( prod ) {                                 // starter ::main
        // 1st resume starts here
        for ( i; N ) {                                                                          // N pairs of values
                int p1 = random( 100 ), p2 = random( 100 );
                sout | p1 | " " | p2;
                int status = delivery( c, p1, p2 );
                sout | " $" | money | nl | status;
                receipt += 1;
        }
        stop( c );
        sout | "prod stops";
}
int payment( Prod & prod, int m ) with(prod) {
        money = m;
        resume( prod );                                                                         // main 1st time, then
        return receipt;                                                                         // prod in delivery
}
void start( Prod & prod, int N, Cons &c ) {
        &prod.c = &c;
        prod.[N, receipt] = [N, 0];
        resume( prod );                                                                         // activate main
}
coroutine Cons {
        Prod & p;
        int p1, p2, status;
        bool done;
};
void ?{}( Cons & cons, Prod & p ) {
        &cons.p = &p;
        cons.[status, done ] = [0, false];
}
void ^?{}( Cons & cons ) {}
void main( Cons & cons ) with( cons ) {                                 // starter prod
        // 1st resume starts here
        int money = 1, receipt;
        for ( ; ! done; ) {
                sout | p1 | " " | p2 | nl | " $" | money;
                status += 1;
                receipt = payment( p, money );
                sout | " #" | receipt;
                money += 1;
        }
        sout | "cons stops";
}
int delivery( Cons & cons, int p1, int p2 ) {
        cons.[p1, p2] = [p1, p2];
        resume( cons );                                                                         // main 1st time, then
        return cons.status;                                                                     // cons in payment
}
void stop( Cons & cons ) {
        cons.done = true;
        resume( cons );                                                                         // activate payment
}
int main() {
        Prod prod;
        Cons cons = { prod };
        srandom( getpid() );
        start( prod, 5, cons );
}

// Local Variables: //
// tab-width: 4 //
// compile-command: "cfa ProdCons.cfa" //
// End: //