kernel: $and? / $or? short-circuit + 10 tests [shapes-reflective]

Operatives (not applicatives) so untaken args are not evaluated. Empty
$and? = true, empty $or? = false (Kernel identity convention). Returns
last evaluated value, not bool-coerced. Sketched reflective short-
circuit API: identical protocol across reflective Lisps because
operative semantics are forced — an applicative variant defeats the
purpose. 252 tests total.

lib/kernel/runtime.sx

@@ -288,6 +288,38 @@
               (c (knl-cond-eval-body (rest args) dyn-env))
               (:else nil))))))))
 
+;; $and? — short-circuit AND. Operative (not applicative) so untaken
+;; clauses are NOT evaluated. Empty $and? returns true (the identity).
+(define knl-and?-impl
+  (fn (args dyn-env)
+    (cond
+      ((or (nil? args) (= (length args) 0)) true)
+      ((= (length args) 1) (kernel-eval (first args) dyn-env))
+      (:else
+        (let ((v (kernel-eval (first args) dyn-env)))
+          (cond
+            (v (knl-and?-impl (rest args) dyn-env))
+            (:else v)))))))
+
+(define kernel-and?-operative
+  (kernel-make-primitive-operative knl-and?-impl))
+
+;; $or? — short-circuit OR. Operative; untaken clauses NOT evaluated.
+;; Empty $or? returns false (the identity).
+(define knl-or?-impl
+  (fn (args dyn-env)
+    (cond
+      ((or (nil? args) (= (length args) 0)) false)
+      ((= (length args) 1) (kernel-eval (first args) dyn-env))
+      (:else
+        (let ((v (kernel-eval (first args) dyn-env)))
+          (cond
+            (v v)
+            (:else (knl-or?-impl (rest args) dyn-env))))))))
+
+(define kernel-or?-operative
+  (kernel-make-primitive-operative knl-or?-impl))
+
 ;; $unless COND BODY... — evaluate body iff COND is falsy; else nil.
 (define kernel-unless-operative
   (kernel-make-primitive-operative
@@ -581,6 +613,8 @@
       (kernel-env-bind! env "$cond"   kernel-cond-operative)
       (kernel-env-bind! env "$when"   kernel-when-operative)
       (kernel-env-bind! env "$unless" kernel-unless-operative)
+      (kernel-env-bind! env "$and?"   kernel-and?-operative)
+      (kernel-env-bind! env "$or?"    kernel-or?-operative)
       (kernel-env-bind! env "eval" kernel-eval-applicative)
       (kernel-env-bind!
         env

lib/kernel/tests/standard.sx

@@ -319,4 +319,22 @@
 (ks-test "unless: skips body when true"
   (ks-eval "($unless #t nope)") nil)
 
+;; ── $and? / $or? short-circuit ──────────────────────────────────
+(ks-test "and: empty returns true"   (ks-eval "($and?)") true)
+(ks-test "and: single returns value" (ks-eval "($and? 42)") 42)
+(ks-test "and: all true returns last"
+  (ks-eval "($and? 1 2 3)") 3)
+(ks-test "and: first false short-circuits"
+  (ks-eval "($and? #f nope)") false)
+(ks-test "and: false in middle short-circuits"
+  (ks-eval "($and? 1 #f nope)") false)
+(ks-test "or: empty returns false"  (ks-eval "($or?)") false)
+(ks-test "or: single returns value" (ks-eval "($or? 42)") 42)
+(ks-test "or: first truthy short-circuits"
+  (ks-eval "($or? 99 nope)") 99)
+(ks-test "or: all false returns last"
+  (ks-eval "($or? #f #f #f)") false)
+(ks-test "or: middle truthy"
+  (ks-eval "($or? #f 42 nope)") 42)
+
 (define ks-tests-run! (fn () {:total (+ ks-test-pass ks-test-fail) :passed ks-test-pass :failed ks-test-fail :fails ks-test-fails}))

plans/kernel-on-sx.md

@@ -108,6 +108,12 @@ When the second consumer arrives, the extraction work is: rename `kernel-*` →
 
 **May propose:** `lib/guest/reflective/` sub-layer — environment manipulation, evaluator-as-value, applicative/operative dispatch protocols.
 
+**Proposed `lib/guest/reflective/short-circuit.sx` API** (from $and?/$or? chiselling — pending second consumer):
+- `(refl-short-and? ARGS DYN-ENV)` — recursive walker; evaluates each in DYN-ENV, returns first falsy value or last truthy. Identity is `true`.
+- `(refl-short-or? ARGS DYN-ENV)` — symmetric; returns first truthy or last falsy. Identity is `false`.
+- Both must be defined as operatives in any reflective Lisp because short-circuit semantics require staged evaluation — an applicative would force every argument before any decision could be made.
+- Driving insight: short-circuit booleans are a forcing function for "operative semantics matter". Languages that lack first-class operatives have to special-case these as keywords; languages with operatives get them for free, in user code.
+
 **Proposed `lib/guest/reflective/quoting.sx` API** (from quasiquote chiselling — pending second consumer):
 - `(refl-quasi-walk FORM ENV)` — top-level entry. Recursively walks FORM; an `$unquote` sub-expression is evaluated in ENV and replaces itself in the result.
 - `(refl-quasi-walk-list FORMS ENV)` — walks a list of forms, splicing `$unquote-splicing` results inline.
@@ -154,6 +160,7 @@ The motivation is that SX's host `make-env` family is registered only in HTTP/si
 
 ## Progress log
 
+- 2026-05-11 — `$and?` / `$or?` short-circuit booleans. Operatives (not applicatives) so untaken arguments are NOT evaluated. Identity values: `$and?` empty = true, `$or?` empty = false. Returns the last evaluated value (Kernel convention — not coerced to bool). 10 new tests including the short-circuit verification (`($and? #f nope)` returns false without evaluating `nope`). chisel: shapes-reflective. Sketched `lib/guest/reflective/short-circuit.sx` API; the protocol is identical across reflective Lisps because short-circuit FORCES operative semantics — an applicative variant would defeat the purpose. 252 tests total.
 - 2026-05-11 — `$cond` / `$when` / `$unless`. Standard Kernel control flow added: `$cond` walks clauses in order, evaluates first truthy test, runs that clause's body in sequence; `else` is the catch-all symbol; empty cond and no-match cond return nil. `$when` and `$unless` are simple conditional execution. All three preserve hygiene (clauses not taken are NOT evaluated). 12 new tests in `tests/standard.sx`. chisel: nothing. 242 tests total. (Third `nothing` in a row but allowable here — these are textbook Kernel idioms with no novel reflective angle.)
 - 2026-05-11 — `$quasiquote` runtime. The parser's reader macros (Phase 1.5) produced unevaluated `$quasiquote`/`$unquote`/`$unquote-splicing` forms; the runtime side now interprets them. `kernel-quasiquote-operative` walks the template via mutual recursion `knl-quasi-walk` ↔ `knl-quasi-walk-list`: atoms and empty lists pass through; an `($unquote X)` head form returns `(kernel-eval X dyn-env)`; an `($unquote-splicing X)` *inside* a list evaluates X and splices its list result via `knl-list-concat`. Nesting depth (`` `\`...\` ``) is not tracked — for Phase-1.5 simplicity, nested quasiquotes flatten. 8 new tests in `tests/standard.sx`. chisel: shapes-reflective. The quoting walker shape is universal across reflective Lisps; sketched the `lib/guest/reflective/quoting.sx` candidate API (`refl-quasi-walk`, `refl-quasi-walk-list`, `refl-list-concat`). 230 tests total.
 - 2026-05-11 — Multi-expression body for `$vau`/`$lambda`. Both forms now accept `(formals env-param body1 body2 ...)` / `(formals body1 body2 ...)`. Implementation: `:body` slot now holds a LIST of forms (was a single expression); `kernel-call-operative` calls a new `knl-eval-body` that evaluates each in sequence, returning the last. No dependency on `$sequence` being in static-env — the iteration lives at the host level. 5 new tests in `tests/vau.sx` (multi-body lambda, multi-body vau, sequenced `$define!`, zero-arg multi-body). chisel: nothing (Kernel-internal improvement; doesn't change the reflective API surface). 223 tests total.