Orkuncakilkaya
808c4a6f7a
action Name { fields } is a typed record; reducer State on Action(s: mut State, a: Action) { ... }
in the module that owns the state takes exactly that state and the action (a second state is
refused); dispatch Action { fields } queues one from anywhere, the queue supplied by the runtime.
The queue is drained at the end of every phase of the frame loop, after every phase of ludic.base's
core_tick_all, and by drain_actions(): in dispatch order, each action's reducers in the order of
their states' names, an action a reducer dispatches queued behind, a queue still growing after 64
rounds stopped with the action named. Examples actions/pack, phases, runaway; rejects for a second
state, a reducer on a non-action and an unknown dispatch; ludic.base's actions_test; LANGUAGE.md.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
38 lines
1.3 KiB
Text
38 lines
1.3 KiB
Text
# pack.ludic - 0.R: what happened is an action; what it means for a state is that state's reducer.
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# The entry dispatches; drain_actions() runs every reducer of each action, in order, each given its
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# own state - and an action a reducer dispatches goes behind the queue.
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program PackActions {
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state Pack {
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items: []int = new []int
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weight: int = 0
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}
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state Log {
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lines: []string = new []string
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}
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action PickUp { item: int, kg: int = 1 }
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action Drop { item: int }
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action Overload {}
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reducer Pack on PickUp(p: mut Pack, a: PickUp) {
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push(p.items, a.item)
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p.weight += a.kg
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if p.weight > 10 { dispatch Overload {} }
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}
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reducer Log on PickUp(l: mut Log, a: PickUp) { push(l.lines, `picked {a.item}`) }
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reducer Pack on Drop(p: mut Pack, a: Drop) {
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var kept = new []int
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for i in 0 .. len(p.items) { if p.items[i] != a.item { push(kept, p.items[i]) } }
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p.items = kept
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}
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reducer Log on Overload(l: mut Log, a: Overload) { push(l.lines, "too heavy") }
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entry (p: Pack, l: Log) {
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dispatch PickUp { item: 7 }
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dispatch PickUp { item: 9, kg: 12 }
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dispatch Drop { item: 7 }
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print(len(p.items)) # 0: nothing is reduced until the queue is drained
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drain_actions()
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print(`{len(p.items)} {p.items[0]} {p.weight}`)
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for i in 0 .. len(l.lines) { print(l.lines[i]) }
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}
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}
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