archive/1.vm/channel.mu

   1 # example program: communicating between routines using channels
   2
   3 def producer sink:&:sink:char -> sink:&:sink:char [
   4   # produce characters 1 to 5 on a channel
   5   local-scope
   6   load-inputs
   7   # n = 0
   8   n:char <- copy 0
   9   {
  10     done?:bool <- lesser-than n, 5
  11     break-unless done?
  12     # other threads might get between these prints
  13     $print [produce: ], n, [
  14 ]
  15     sink <- write sink, n
  16     n <- add n, 1
  17     loop
  18   }
  19   close sink
  20 ]
  21
  22 def consumer source:&:source:char -> source:&:source:char [
  23   # consume and print integers from a channel
  24   local-scope
  25   load-inputs
  26   {
  27     # read an integer from the channel
  28     n:char, eof?:bool, source <- read source
  29     break-if eof?
  30     # other threads might get between these prints
  31     $print [consume: ], n:char, [
  32 ]
  33     loop
  34   }
  35 ]
  36
  37 def main [
  38   local-scope
  39   source:&:source:char, sink:&:sink:char <- new-channel 3/capacity
  40   # create two background 'routines' that communicate by a channel
  41   routine1:num <- start-running producer, sink
  42   routine2:num <- start-running consumer, source
  43   wait-for-routine routine1
  44   wait-for-routine routine2
  45 ]