# example program: communicating between routines using channels
def producer sink:&:sink:char -> sink:&:sink:char [
# produce characters 1 to 5 on a channel
local-scope
load-inputs
# n = 0
n:char <- copy 0
{
done?:bool <- lesser-than n, 5
break-unless done?
# other threads might get between these prints
$print [produce: ], n, [
]
sink <- write sink, n
n <- add n, 1
loop
}
close sink
]
def consumer source:&:source:char -> source:&:source:char [
# consume and print integers from a channel
local-scope
load-inputs
{
# read an integer from the channel
n:char, eof?:bool, source <- read source
break-if eof?
# other threads might get between these prints
$print [consume: ], n:char, [
]
loop
}
]
def main [
local-scope
source:&:source:char, sink:&:sink:char <- new-channel 3/capacity
# create two background 'routines' that communicate by a channel
routine1:num <- start-running producer, sink
routine2:num <- start-running consumer, source
wait-for-routine routine1
wait-for-routine routine2
]