# Example program showing that a 'paused' continuation can be 'resumed' with
# ingredients.
#
# Print out a list of numbers, first adding 0 to the first, 1 to the second, 2
# to the third, and so on.
def main [
local-scope
l:&:list:num <- copy 0
l <- push 3, l
l <- push 2, l
l <- push 1, l
k:continuation, x:num, done?:bool <- call-with-continuation-mark create-yielder, l
a:num <- copy 1
{
break-if done?
$print x 10/newline
k, x:num, done?:bool <- call k, a # resume; x = a + next l value
a <- add a, 1
loop
}
]
def create-yielder l:&:list:num -> n:num, done?:bool [
local-scope
load-ingredients
a:num <- copy 0
{
done? <- equal l, 0
break-if done?
n <- first l
l <- rest l
n <- add n, a
a <- return-continuation-until-mark n, done? # pause/resume
loop
}
return-continuation-until-mark -1, done?
assert 0/false, [called too many times, ran out of continuations to return]
]