Orkuncakilkaya
ab0b84b87e
An action names one row of a ludic.base Table<T> by its handle, in a field marked @Target, and `reducer Deer in Herd.deer on Spook(r: mut Row<Deer>, n: Noise, a: Spook)` runs once, for that row alone (the table may sit down a path, S.w.tab). The drain resolves the handle (tb_row) and hands the reducer a Row<T> - new in ludic.base: tb, row, h, rec - that the queue keeps, one per row reducer, filled in place, so a targeted action allocates nothing; a stale handle runs nothing, and LUDIC_ACTIONS_LOG=1 prints a line for it (@alloc_ok). Row reducers order among an action's by their state's name, then the table's path. Checked at compile time (actions_rows.ludic): the row reaches r.rec and r.h only - r.tb / r.row refused, the view never assigned, stored, copied or handed on except to a @RowVerb (a function of the record's own module taking Row<T> first; any other function taking a row is refused); a field marked @Column (a table column mirrors it) is not written through r.rec; only the module owning the state declares a row reducer; one @Target, an int, per action; the states between the row and the action are read. `mut` is allowed on a Row<T> parameter. ludic schema's code section gains row_reducers (record, table, state, action, target, predicted, net, module, at) and row_verbs (name, record, module, at), and every action its target; row reducers are left out of `reducers`. ludic deps and ludic-lsp name a row reducer `reducer Deer in Herd.deer on Spook`. vocab: @Target, @Column, @RowVerb; docs/language pages; LANGUAGE.md "A reducer on a row"; examples actions/rows and ten rejects; test.ludic feat, reject and schema cases (not run); changes/row-reducers.md. Reseeded; bootstrap-cfree fixpoint holds (307497 lines); Maroon Lake's `ludic build --check` is clean against this tree. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
44 lines
1.9 KiB
Text
44 lines
1.9 KiB
Text
# rows.ludic - 27.3: a reducer on a row. An action that names one row of a Table by its handle
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# (@Target) is reduced for that row alone: the drain resolves the handle and hands the reducer a
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# Row it keeps, so nothing is allocated. A field a column mirrors (@Column) is written only by the
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# record's @RowVerbs, which keep the column with it; a handle whose row is gone runs nothing.
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import "ludic.base"
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program RowActions {
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numbers float
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property Deer {
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@Column x: float = 0.0 # mirrored by column 0 of the herd's table
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fear: int = 0
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}
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state Herd { deer: Table<Deer> = null }
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state Noise { loud: int = 2 }
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action Spook { @Target who: int = -1, by: int = 1 }
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action Bolt { @Target who: int = -1, dx: float = 0.0 }
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reducer Deer in Herd.deer on Spook(r: mut Row<Deer>, n: Noise, a: Spook) {
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r.rec.fear += a.by * n.loud
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if r.rec.fear > 3 { dispatch Bolt { who: r.h, dx: 5.0 } } # a follow-on, for the same row
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}
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reducer Deer in Herd.deer on Bolt(r: mut Row<Deer>, a: Bolt) { deer_move(r, r.rec.x + a.dx) }
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reducer Noise on Spook(n: mut Noise, a: Spook) { n.loud += 1 } # a state's reducer on the same action
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@RowVerb function deer_move(r: mut Row<Deer>, x: float) -> void {
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r.rec.x = x
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tb_set_f(r.tb, 0, r.row, x)
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}
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entry (h: mut Herd) {
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let tb: Table<Deer> = table_new(1, 0)
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h.deer = tb
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let a = tb_add(tb, new Deer)
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let b = tb_add(tb, new Deer { x: 10.0 })
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let c = tb_add(tb, new Deer)
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tb_remove(tb, c)
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dispatch Spook { who: a, by: 1 } # Noise's reducer runs after Deer's: 2, then 3 for b
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dispatch Spook { who: b, by: 2 } # 6 > 3: b bolts
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dispatch Spook { who: c, by: 9 } # c is gone: its row reducers run nothing
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drain_actions()
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let ra = tb_row(tb, a)
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let rb = tb_row(tb, b)
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print(`{tb_rec(tb, ra).fear} {tb_rec(tb, rb).fear} {int(tb_rec(tb, rb).x)} {int(tb_f(tb, 0, rb))}`)
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}
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}
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