Chez Phase 2 (inc S): atom watches + validators (jolt-mn9o)

The Chez atom record gains watches (an alist of key->fn) and validator
slots. swap!/reset! now validate the candidate value before storing and
notify watches after, in the seed's order (core_refs.janet) — the watch fn
is called (key ref old new). compare-and-set!/swap-vals!/reset-vals! route
through reset!/swap! so they validate + notify too.

add-watch/remove-watch/set-validator!/get-validator are native here and
re-asserted in post-prelude.ss: the clojure.core overlay implements them via
jolt.host/ref-put! on (get atom :watches), a Janet-table mutation a Chez atom
record can't answer, so its def-var! would otherwise clobber these. set-
validator! validates the current value immediately (Clojure throws if already
invalid).

Parity 2150 -> 2154, 0 new divergences. New test/chez/_atomwatch.janet 10/10.

The (class x) native and the clojure.walk port were explored this increment
but deferred: class alone makes the String-class-token corpus cases emit-and-
run with a wrong value (the bare token doesn't resolve yet) — filed jolt-13zk
to land the native together with token resolution; clojure.walk is blocked on
list? + map-entry-as-vector (jolt-75sv).

test/chez/_atomwatch.janet

@@ -0,0 +1,51 @@
+# jolt-mn9o — atom watches + validators on Chez. The Chez atom record carries
+# watches (alist) + validator slots; swap!/reset! validate-then-set-then-notify;
+# add-watch/remove-watch/set-validator!/get-validator are native (post-prelude.ss
+# re-asserts them over the overlay's ref-put!-based versions). Oracle = build/jolt.
+#
+#   janet test/chez/_atomwatch.janet
+(def jolt-bin (or (os/getenv "JOLT_BIN") "bin/jolt-chez"))
+
+# [expr throws?] — when throws? the case is expected to exit non-zero on both
+# (the corpus :throws contract; the exception message text may differ).
+(def cases
+  [["(let [a (atom 0) seen (atom 0)] (add-watch a :k (fn [k r o n] (reset! seen 1))) (reset! a 5) @seen)" false]
+   ["(let [a (atom 0) seen (atom 0)] (add-watch a :k (fn [k r o n] (swap! seen inc))) (remove-watch a :k) (reset! a 5) @seen)" false]
+   ["(let [a (atom 0) log (atom [])] (add-watch a :k (fn [k r o n] (swap! log conj [o n]))) (reset! a 1) (reset! a 2) @log)" false]
+   ["(let [a (atom 0)] (set-validator! a number?) (reset! a 5) @a)" false]
+   ["(let [a (atom 5)] (set-validator! a pos?) (swap! a inc) @a)" false]
+   ["(let [a (atom 0)] (set-validator! a number?) (fn? (get-validator a)))" false]
+   ["(let [a (atom 0)] (nil? (get-validator a)))" false]
+   ["(let [a (atom 0)] (set-validator! a pos?) (reset! a -1))" true]
+   ["(let [a (atom 5)] (set-validator! a pos?) (swap! a (fn [_] -1)) @a)" true]
+   ["(let [a (atom 0) c (atom 0)] (add-watch a :k (fn [k r o n] (swap! c inc))) (swap! a inc) (swap! a inc) @c)" false]])
+
+(defn run-capture [bin expr]
+  (def proc (os/spawn [bin "-e" expr] :p {:out :pipe :err :pipe}))
+  (def out (ev/read (proc :out) 0x100000))
+  (def err (ev/read (proc :err) 0x100000))
+  (def code (os/proc-wait proc))
+  (def lines (filter (fn [l] (not (empty? l)))
+                     (string/split "\n" (string/trim (if out (string out) "")))))
+  [code (if (empty? lines) "" (last lines)) (string/trim (if err (string err) ""))])
+
+(var pass 0)
+(def fails @[])
+(each [expr throws?] cases
+  (def [ocode oracle _] (run-capture "build/jolt" expr))
+  (def [code got err] (run-capture jolt-bin expr))
+  (cond
+    throws?
+      (if (and (not= ocode 0) (not= code 0)) (++ pass)
+        (array/push fails [expr (string "expected both throw; oracle exit " ocode ", chez exit " code)]))
+    (not= ocode 0) (array/push fails [expr (string "ORACLE FAILED exit " ocode)])
+    (not= code 0) (array/push fails [expr (string "exit " code "; err: " err)])
+    (= got oracle) (++ pass)
+    (array/push fails [expr (string "want `" oracle "`, got `" got "`")])))
+
+(printf "\n_atomwatch parity [%s]: %d/%d passed" jolt-bin pass (length cases))
+(when (> (length fails) 0)
+  (printf "%d FAIL(s):" (length fails))
+  (each [e m] fails (printf "  FAIL %s\n    %s" e m)))
+(flush)
+(os/exit (if (empty? fails) 0 1))

test/chez/run-corpus-prelude.janet

@@ -240,8 +240,12 @@
 # map member dispatch, and the seed's universal object-methods getMessage/getCause/
 # toString/hashCode/equals. Also added getMessage/getLocalizedMessage/equals to the
 # string method surface so a thrown string / Exception. ctor answers .getMessage) 2150.
+# jolt-mn9o (atom watches/validators — the Chez atom record carries watches/
+# validator slots; swap!/reset! validate-then-set-then-notify in seed order;
+# add-watch/remove-watch/set-validator!/get-validator are native and re-asserted
+# in post-prelude.ss over the overlay's ref-put!-on-a-Janet-table versions) 2154.
 # Strided runs scale down.
-(def base-floor (scan-number (or (os/getenv "JOLT_CHEZ_PRELUDE_FLOOR") "2150")))
+(def base-floor (scan-number (or (os/getenv "JOLT_CHEZ_PRELUDE_FLOOR") "2154")))
 (def floor (if (os/getenv "JOLT_CORPUS_LIMIT") 0 base-floor))
 (when (or (> (length diverged) 0) (< pass floor))
   (printf "REGRESSION: pass %d < floor %d or %d new divergence(s)" pass floor (length diverged)))