resource reader
   import Reader_Writer
body reader(i : int; nap_time : int)
   write("reader", i, "is alive, nap_time =", nap_time)

   process reading
      var napping : int
      do true ->
         napping := int(random(1000*nap_time))
         write("age=", age(), "reader", i, "napping for", napping)
         nap(napping)
         write("age=", age(), "reader", i, "wants to read")
         Reader_Writer.Start_Read(i)
         napping := int(random(1000*nap_time))
         write("age=", age(), "reader", i, "begins reading for", napping)
         nap(napping)
         Reader_Writer.End_Read(i)
         write("age=", age(), "reader", i, "finished reading")
      od
   end reading
end reader

resource writer
   import Reader_Writer
body writer(i : int; nap_time : int)
   write("WRITER", i, "is alive, nap_time =", nap_time)

   process writing
      var napping : int
      do true ->
         napping := int(random(1000*nap_time))
         write("age=", age(), "WRITER", i, "napping for", napping)
         nap(napping)
         write("age=", age(), "WRITER", i, "wants to write")
         Reader_Writer.Start_Write(i)
         napping := int(random(1000*nap_time))
         write("age=", age(), "WRITER", i, "is writing for", napping)
         nap(napping)
         write("age=", age(), "WRITER", i, "is finished writing")
         Reader_Writer.End_Write(i)
      od
   end writing
end writer

resource start()
   import writer, reader, Reader_Writer
   var readers : int := 10, writers : int := 5, nap_time : int := 3
   var run_time : int := 60
   getarg(1, readers); getarg(2, writers); getarg(3, nap_time)
   getarg(4, run_time)
   write(readers, "readers and", writers,
      "writers starting with nap_time", nap_time, "and run_time", run_time)
   fa i := 1 to readers -> create reader(i, nap_time) af
   fa i := 1 to writers -> create writer(i, nap_time) af
   nap(1000*run_time); write("must stop now"); stop
end start

/* ............... Example compile and run(s)

% m2sr -sx rw.m
% sr -o rw rw.sr driver.sr
rw.sr:
driver.sr:
rw.sr:
driver.sr:
linking:
% rw 5 2 1 10
5 readers and 2 writers starting with nap_time 1 and run_time 10
reader 1 is alive, nap_time = 1
age= 64 reader 1 napping for 585
reader 2 is alive, nap_time = 1
age= 80 reader 2 napping for 44
reader 3 is alive, nap_time = 1
age= 106 reader 3 napping for 682
reader 4 is alive, nap_time = 1
age= 137 reader 4 napping for 406
age= 166 reader 2 wants to read
reader 5 is alive, nap_time = 1
age= 174 reader 5 napping for 970
   age= 184 reader 2 has begun reading, Readers= 1
WRITER 1 is alive, nap_time = 1
age= 193 WRITER 1 napping for 809
age= 235 reader 2 begins reading for 124
WRITER 2 is alive, nap_time = 1
age= 248 WRITER 2 napping for 320
   age= 370 reader 2 finished reading, Readers= 0
age= 374 reader 2 finished reading
age= 382 reader 2 napping for 844
age= 552 reader 4 wants to read
   age= 557 reader 4 has begun reading, Readers= 1
age= 566 reader 4 begins reading for 12
age= 579 WRITER 2 wants to write
   age= 586 reader 4 finished reading, Readers= 0
age= 604 reader 4 finished reading
age= 608 reader 4 napping for 861
      age= 611 WRITER 2 has begun Writing,
age= 614 WRITER 2 is writing for 409
age= 659 reader 1 wants to read
age= 800 reader 3 wants to read
age= 1019 WRITER 1 wants to write
age= 1031 WRITER 2 is finished writing
   age= 1035 WRITER 2 has finished Writing
age= 1046 WRITER 2 napping for 498
   age= 1049 reader 1 has begun reading, Readers= 1
age= 1056 reader 1 begins reading for 191
   age= 1068 reader 3 has begun reading, Readers= 2
age= 1078 reader 3 begins reading for 514
age= 1151 reader 5 wants to read
   age= 1171 reader 5 has to WAIT
age= 1240 reader 2 wants to read
   age= 1245 reader 2 has to WAIT
   age= 1261 reader 1 finished reading, Readers= 1
age= 1279 reader 1 finished reading
age= 1285 reader 1 napping for 520
age= 1479 reader 4 wants to read
   age= 1489 reader 4 has to WAIT
age= 1549 WRITER 2 wants to write
   age= 1607 reader 3 finished reading, Readers= 0
age= 1612 reader 3 finished reading
age= 1615 reader 3 napping for 766
      age= 1620 WRITER 1 has begun Writing,
age= 1628 WRITER 1 is writing for 774
age= 1809 reader 1 wants to read
age= 2389 reader 3 wants to read
age= 2425 WRITER 1 is finished writing
   age= 2430 WRITER 1 has finished Writing
age= 2435 WRITER 1 napping for 582
   age= 2438 reader 5 has begun reading, Readers= 1
age= 2443 reader 5 begins reading for 629
   age= 2459 reader 2 has begun reading, Readers= 2
age= 2464 reader 2 begins reading for 717
   age= 2468 reader 4 has begun reading, Readers= 3
age= 2474 reader 4 begins reading for 565
   age= 2477 reader 1 has begun reading, Readers= 4
age= 2492 reader 1 begins reading for 499
   age= 2497 reader 3 has begun reading, Readers= 5
age= 2506 reader 3 begins reading for 933
   age= 3004 reader 1 finished reading, Readers= 4
 ...
must stop now
                                              */