48 lines
1.1 KiB
Forth
48 lines
1.1 KiB
Forth
# Example program showing 'return-continuation-until-mark' return other values
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# alongside continuations.
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#
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# Print out a given list of numbers.
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#
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# To run:
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# $ git clone https://github.com/akkartik/mu
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# $ cd mu
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# $ ./mu continuation4.mu
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#
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# Expected output:
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# 1
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# 2
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# 3
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def main [
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local-scope
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l:&:list:num <- copy null
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l <- push 3, l
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l <- push 2, l
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l <- push 1, l
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k:continuation, x:num, done?:bool <- call-with-continuation-mark 100/mark, create-yielder, l
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{
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break-if done?
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$print x 10/newline
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k, x:num, done?:bool <- call k
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loop
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}
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]
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def create-yielder l:&:list:num -> n:num, done?:bool [
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local-scope
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load-inputs
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{
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done? <- equal l, null
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break-if done?
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n <- first l
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l <- rest l
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return-continuation-until-mark 100/mark, n, done?
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loop
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}
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# A function that returns continuations shouldn't get the opportunity to
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# return. Calling functions should stop calling its continuation after this
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# point.
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return-continuation-until-mark 100/mark, -1, done?
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assert false, [called too many times, ran out of continuations to return]
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]
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