kernel: multi-expression body for $vau/$lambda + 5 tests [nothing]

:body slot holds a LIST of forms now (was single expression). New
knl-eval-body in eval.sx evaluates each form in sequence, returning
the last. $vau and $lambda accept (formals env-param body...) /
(formals body...). No $sequence dependency. 223 tests total.

lib/kernel/eval.sx

@@ -172,9 +172,19 @@
             (when
               (not (= eparam :knl-ignore))
               (kernel-env-bind! local eparam dyn-env)))
-          (kernel-eval (get op :body) local)))
+          ;; :body is a list of forms — evaluate in sequence, return last.
+          (knl-eval-body (get op :body) local)))
       (:else (error "kernel-call-operative: malformed operative")))))
 
+(define knl-eval-body
+  (fn (forms env)
+    (cond
+      ((= (length forms) 1) (kernel-eval (first forms) env))
+      (:else
+        (begin
+          (kernel-eval (first forms) env)
+          (knl-eval-body (rest forms) env))))))
+
 ;; Phase 3 supports a flat parameter list only — destructuring later.
 (define
   kernel-bind-params!

lib/kernel/runtime.sx

@@ -40,13 +40,13 @@
   (fn
     (args dyn-env)
     (cond
-      ((not (= (length args) 3))
-        (error "$vau: expects (formals env-param body)"))
+      ((< (length args) 3)
+        (error "$vau: expects (formals env-param body...)"))
       (:else
         (let
           ((formals (first args))
             (eparam-raw (nth args 1))
-            (body (nth args 2)))
+            (body-forms (rest (rest args))))
           (cond
             ((not (knl-formals-ok? formals))
               (error "$vau: formals must be a list of symbols"))
@@ -56,7 +56,7 @@
               (kernel-make-user-operative
                 formals
                 (knl-eparam-sentinel eparam-raw)
-                body
+                body-forms
                 dyn-env))))))))
 
 (define
@@ -70,17 +70,21 @@
   (fn
     (args dyn-env)
     (cond
-      ((not (= (length args) 2))
-        (error "$lambda: expects (formals body)"))
+      ((< (length args) 2)
+        (error "$lambda: expects (formals body...)"))
       (:else
         (let
-          ((formals (first args)) (body (nth args 1)))
+          ((formals (first args)) (body-forms (rest args)))
           (cond
             ((not (knl-formals-ok? formals))
               (error "$lambda: formals must be a list of symbols"))
             (:else
               (kernel-wrap
-                (kernel-make-user-operative formals :knl-ignore body dyn-env)))))))))
+                (kernel-make-user-operative
+                  formals
+                  :knl-ignore
+                  body-forms
+                  dyn-env)))))))))
 
 (define
   kernel-lambda-operative

lib/kernel/tests/vau.sx

@@ -286,4 +286,24 @@
   (guard (e (true :raised)) (kv-eval-src "(unwrap 42)" (kv-make-env)))
   :raised)
 
+;; ── Multi-expression body (implicit $sequence) ──────────────────
+
+(kv-test "lambda: two body forms — value of last"
+  (kv-eval-src "(($lambda (n) (+ n 1) (+ n 10)) 5)" (kv-make-env)) 15)
+
+(kv-test "lambda: three body forms"
+  (kv-eval-src "(($lambda (n) n (+ n 1) (+ n 2)) 10)" (kv-make-env)) 12)
+
+(kv-test "vau: two body forms"
+  (kv-eval-src "(($vau (a b) _ a (list a b)) 7 8)" (kv-make-env))
+  (list 7 8))
+
+(kv-test "lambda: $define! in early body visible in later body"
+  (kv-eval-src
+    "(($lambda (n) ($define! double (+ n n)) double) 6)"
+    (kv-make-env)) 12)
+
+(kv-test "lambda: zero-arg multi-body"
+  (kv-eval-src "(($lambda () 1 2 3))" (kv-make-env)) 3)
+
 (define kv-tests-run! (fn () {:total (+ kv-test-pass kv-test-fail) :passed kv-test-pass :failed kv-test-fail :fails kv-test-fails}))