mk: phase 7 — table-1 + table-3, Ackermann canary

Two more arities of the naive memoization wrapper:

table-1: predicate (1-arg) tabling. Cache entry is :ok / :no.
  Demonstrated with a tabled membero-as-predicate.

table-3: 3-arg (i1 i2 output) tabling. Cache key joins the two
  inputs; cache value is the output value list.
  Canonical demo: tabled Ackermann.

  (ack-o 0 0 q) -> 1
  (ack-o 2 3 q) -> 9
  (ack-o 3 3 q) -> 61

A(3,3) executes A(2,..) many times, A(1,..) more, A(0,..) most. With
table-3 each (m, n) pair is computed once.

6 new tests, 644/644 cumulative.

lib/minikanren/tabling.sx

@@ -89,3 +89,69 @@
                             (mk-tab-replay-vals vals output s)))))
                     (:else (mk-tab-replay-vals cached output s))))))
             (:else ((rel-fn input output) s))))))))
+
+;; --- table-1: 1-arg relation (one input, no output to cache) ---
+;; The relation is a predicate `(p input)` that succeeds or fails.
+;; Cache stores either :ok or :no.
+
+(define
+  table-1
+  (fn
+    (name rel-fn)
+    (fn
+      (input)
+      (fn
+        (s)
+        (let
+          ((winput (mk-walk* input s)))
+          (cond
+            ((mk-tab-ground-term? winput)
+              (let
+                ((key (str name "@1@" winput)))
+                (let
+                  ((cached (mk-tab-lookup key)))
+                  (cond
+                    ((= cached :miss)
+                      (let
+                        ((stream ((rel-fn input) s)))
+                        (let
+                          ((peek (stream-take 1 stream)))
+                          (cond
+                            ((empty? peek)
+                              (begin (mk-tab-store! key :no) mzero))
+                            (:else (begin (mk-tab-store! key :ok) stream))))))
+                    ((= cached :ok) (unit s))
+                    ((= cached :no) mzero)
+                    (:else mzero)))))
+            (:else ((rel-fn input) s))))))))
+
+;; --- table-3: 3-arg relation (input1 input2 output) ---
+;; Cache keyed by (input1, input2). Output values cached as a list.
+
+(define
+  table-3
+  (fn
+    (name rel-fn)
+    (fn
+      (i1 i2 output)
+      (fn
+        (s)
+        (let
+          ((wi1 (mk-walk* i1 s)) (wi2 (mk-walk* i2 s)))
+          (cond
+            ((and (mk-tab-ground-term? wi1) (mk-tab-ground-term? wi2))
+              (let
+                ((key (str name "@3@" wi1 "/" wi2)))
+                (let
+                  ((cached (mk-tab-lookup key)))
+                  (cond
+                    ((= cached :miss)
+                      (let
+                        ((all-substs (stream-take -1 ((rel-fn i1 i2 output) s))))
+                        (let
+                          ((vals (map (fn (s2) (mk-walk* output s2)) all-substs)))
+                          (begin
+                            (mk-tab-store! key vals)
+                            (mk-tab-replay-vals vals output s)))))
+                    (:else (mk-tab-replay-vals cached output s))))))
+            (:else ((rel-fn i1 i2 output) s))))))))