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Squash merge of 76 commits from loops/minikanren. Adds lib/minikanren/ — a complete miniKanren-on-SX implementation built on top of lib/guest/match.sx, validating the lib-guest unify-and-match kit as intended. Modules (20 .sx files, ~1700 LOC): unify, stream, goals, fresh, conde, condu, conda, run, relations, peano, intarith, project, nafc, matche, fd, queens, defrel, clpfd, tabling Phases 1–5 fully done (core miniKanren API, all classic relations, matche, conda, project, nafc). Phase 6 — native CLP(FD): domain primitives, fd-in / fd-eq / fd-neq / fd-lt / fd-lte / fd-plus / fd-times / fd-distinct / fd-label, with constraint reactivation iterating to fixed point. N-queens via FD: 4-queens 2 solutions, 5-queens 10 solutions (vs naive timeout past N=4). Phase 7 — naive ground-arg tabling: table-1 / table-2 / table-3. Fibonacci canary: tab-fib(25) = 75025 in seconds, naive fib(25) times out at 60s. Ackermann via table-3: A(3,3) = 61. 71 test files, 644+ tests passing across the suite. Producer/consumer SLG (cyclic patho, mutual recursion) deferred — research-grade work. The lib-guest validation experiment is conclusive: lib/minikanren/ unify.sx adds ~50 lines of local logic (custom cfg, deep walk*, fresh counter) over lib/guest/match.sx's ~100-line kit. The kit earns its keep ~3× by line count.
25 lines
859 B
Plaintext
25 lines
859 B
Plaintext
;; lib/minikanren/nafc.sx — Phase 5 piece C: negation as finite failure.
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;;
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;; (nafc g)
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;; succeeds (yields the input substitution) if g has zero answers
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;; against that substitution; fails (mzero) if g has at least one.
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;;
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;; Caveat: `nafc` is unsound under the open-world assumption. It only
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;; makes sense for goals over fully-ground terms, or with the explicit
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;; understanding that adding more facts could flip the answer. Use
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;; `(project (...) ...)` to ensure the relevant vars are ground first.
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;;
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;; Caveat 2: stream-take forces g for at least one answer; if g is
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;; infinitely-ground (say, a divergent search over an unbound list),
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;; nafc itself will diverge. Standard miniKanren limitation.
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(define
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nafc
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(fn
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(g)
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(fn
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(s)
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(let
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((peek (stream-take 1 (g s))))
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(if (empty? peek) (unit s) mzero)))))
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