Orkuncakilkaya
e4265f5fdb
A registry marked `@Machine(Deer.mood)` is the transitions of a machine over that enum field of the records a state's Table<Deer> holds. Its record has from and to (the enum's variants), on: string (an action's name, "" for a transition the tick asks), guard: fn(Row<Deer>, reads...) -> bool and enter: fn(Row<Deer>, reads...) -> void; the states are the enum's variants and the start is the field's default. The rows are data (an .lres or defs), the names the studio already edits. Written by the compiler (machines.ludic, machines_write.ludic): for each action an `on` names, a row reducer in the registry's file (named ..__machine__DeerSteps, so it sits beside the program's own row reducer on the same action, after it): the row's state, the first transition from it on that action whose guard passes, the field set, enter run - guards and enters called by name. When a row leaves a state on a guard alone, `state DeerStepsMachine` (the kept row view) and deer_steps_tick(m: mut DeerStepsMachine, s: mut Herd, reads...), one transition a row a tick. Nothing allocates. The table is the whole machine: the field written anywhere else - an assignment, or a `machine` block's become over it - is a type error (check_stmt.ludic, ck_machine_write). Guards and enters take the row first, are the record's module's, keep a row reducer's rules (and may be handed the row); a guard writes nothing through it. The graph is checked, each error at its row (in the .lres when the rows are there): a state never reached from the start, a state with no way out, an `on` naming no action or an action with no @Target, a self-transition with no guard, two ways out of a state on one trigger behind an unguarded first. Also refused: @Machine off a registry, a field that is not a plain enum with a default, a @Column field, no table (or two) of the record, a transitions record of another shape, a machine outside its table's state's module. ludic schema's code section gains `machines` (registry, record, field, enum, table, start, states, actions, tick, module, at); ludic deps names a machine's reducer `reducer Deer in Herd.deer on Spook (machine DeerSteps)`. vocab @Machine; docs annot-machine, kw-machine; LANGUAGE.md "A machine as data"; examples actions/machine (+ deer_steps.lres) and ten rejects; test.ludic feat, reject and schema cases (not run); changes/machines.md. Reseeded; bootstrap-cfree fixpoint holds (317642 lines); Maroon Lake's `ludic build --check` is clean against this tree. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
24 lines
1.6 KiB
Markdown
24 lines
1.6 KiB
Markdown
---
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id: annot-machine
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name: @Machine
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category: annotations
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kind: annotation
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tokens: @Machine
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sig: @Machine(Deer.mood) registry DeerSteps of DeerStep from "deer_steps.lres"
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tip: A registry of a state machine's transitions over an enum field of a table's rows: the compiler writes its reducers and tick.
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order: 84
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---
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<code>@Machine(Record.field)</code> marks a registry as the transitions of a state machine over that enum field of the records a state's <code>Table<Record></code> holds. The registry's record has <code>from</code> and <code>to</code> (the enum's variants), <code>on</code> (an action's name, or <code>""</code> for a transition the tick asks), and a <code>guard</code> and an <code>enter</code> taking the row first. The start is the field's default. The compiler writes a row reducer for each action an <code>on</code> names and, for the guard-only transitions, <code><registry>_tick</code>; each takes the first transition from the row's state whose guard passes, sets the field and runs <code>enter</code>. Nothing else writes the field. A state never reached, a state with no way out, an <code>on</code> naming no action (or one with no <code>@Target</code>), a self-transition with no guard and a second way out behind an unguarded first on one trigger are compile errors.
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```ludic
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# doc-check: skip — a fragment: the record, the table's state and the functions are elsewhere
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property DeerStep {
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from: Mood = Mood.Calm
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to: Mood = Mood.Calm
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on: string = ""
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guard: fn(Row<Deer>, Herd) -> bool = null
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enter: fn(Row<Deer>, Herd) -> void = null
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}
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@Machine(Deer.mood) registry DeerSteps of DeerStep from "deer_steps.lres"
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```
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