# uses sem array in in stmt
# (i.e., uses O_IN rather than O_RECEIVE)
# but still sem optimizable
resource e1()
   sem f[4] = (1,0,1,1)

   procedure wf()  {
	 for [ j = 1 to 4 ] {
	    writes(?f[j])
	 }
	 write()
   }

   wf()

   for [ j = 1 to 4 ] {
      V(f[j])
   }

   wf()

   for [ j = 4 to 1 by -1 ] {
      P(f[j])
   }

   wf()

   for [ j = 1 to 4 ] {
      V(f[j])
   }

   wf()

   # should block after 8 iterations
   # if not, sems could be pointing at junk
   for [ j = 1 to 20 ] {
      in f[j%4+1]() -> write ("got",j) ni
   }

end