43 lines
1.2 KiB
Racket
43 lines
1.2 KiB
Racket
#lang syndicate
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;; Demonstrates glitch preservation in during/spawn.
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;;
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;; Previously, `spawn` was expanded in place into the new actor's
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;; initial actions. This reordering was confusing, as demonstrated
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;; here: the reordering of `spawn` ahead of the retraction of previous
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;; supply caused uninterrupted supply, even though demand had glitched
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;; and the supply instance had been replaced.
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;;
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;; Buggy output:
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;;
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;; Asserting demand.
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;; Supply asserted.
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;; Glitching demand.
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;; Demand now steady.
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;;
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;; Correct output:
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;;
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;; Asserting demand.
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;; Supply asserted.
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;; Glitching demand.
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;; Demand now steady.
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;; Supply retracted.
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;; Supply asserted.
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(spawn (during/spawn 'demand
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(assert 'intermediate-demand)))
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(spawn (during/spawn 'intermediate-demand
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(assert 'supply)))
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(spawn* (react (on (asserted 'supply) (printf "Supply asserted.\n"))
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(on (retracted 'supply) (printf "Supply retracted.\n")))
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(until (asserted (observe 'demand)))
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(printf "Asserting demand.\n")
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(assert! 'demand)
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(until (asserted 'supply))
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(printf "Glitching demand.\n")
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(retract! 'demand)
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(flush!)
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(assert! 'demand)
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(printf "Demand now steady.\n"))
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