smalltalk: whileTrue:/whileFalse: family pinned + 14 tests

lib/smalltalk/eval.sx

@@ -446,27 +446,29 @@
                 temps)
               (st-eval-seq body frame))))))))
 
+;; whileTrue: / whileTrue / whileFalse: / whileFalse — the receiver is the
+;; condition block; the optional argument is the body block. Per ANSI / Pharo
+;; convention, the loop returns nil regardless of how many iterations ran.
 (define
   st-block-while
   (fn
     (cond-block body-block target)
-    (let ((last nil))
-      (begin
-        (define
-          wh-loop
-          (fn
-            ()
-            (let
-              ((c (st-block-apply cond-block (list))))
-              (when
-                (= c target)
-                (begin
-                  (cond
-                    ((not (= body-block nil))
-                      (set! last (st-block-apply body-block (list)))))
-                  (wh-loop))))))
-        (wh-loop)
-        last))))
+    (begin
+      (define
+        wh-loop
+        (fn
+          ()
+          (let
+            ((c (st-block-apply cond-block (list))))
+            (when
+              (= c target)
+              (begin
+                (cond
+                  ((not (= body-block nil))
+                    (st-block-apply body-block (list))))
+                (wh-loop))))))
+      (wh-loop)
+      nil)))
 
 ;; ── Primitive method table for native receivers ────────────────────────
 ;; Returns the result, or the sentinel :unhandled if no primitive matches —

lib/smalltalk/tests/while.sx

@@ -0,0 +1,145 @@
+;; whileTrue: / whileTrue / whileFalse: / whileFalse tests.
+;;
+;; In Smalltalk these are *ordinary* messages sent to the condition block.
+;; No special-form magic — just block sends. The runtime can intrinsify
+;; them later in the JIT (Tier 1 of bytecode expansion) but the spec-level
+;; semantics are what's pinned here.
+
+(set! st-test-pass 0)
+(set! st-test-fail 0)
+(set! st-test-fails (list))
+
+(st-bootstrap-classes!)
+(define ev (fn (src) (smalltalk-eval src)))
+(define evp (fn (src) (smalltalk-eval-program src)))
+
+;; ── 1. whileTrue: with body — basic counter ──
+(st-test
+  "whileTrue: counts down"
+  (evp "| n | n := 5. [n > 0] whileTrue: [n := n - 1]. ^ n")
+  0)
+
+(st-test
+  "whileTrue: returns nil"
+  (evp "| n | n := 3. ^ [n > 0] whileTrue: [n := n - 1]")
+  nil)
+
+(st-test
+  "whileTrue: zero iterations is fine"
+  (evp "| n | n := 0. [n > 0] whileTrue: [n := n + 1]. ^ n")
+  0)
+
+;; ── 2. whileFalse: with body ──
+(st-test
+  "whileFalse: counts down (cond becomes true)"
+  (evp "| n | n := 5. [n <= 0] whileFalse: [n := n - 1]. ^ n")
+  0)
+
+(st-test
+  "whileFalse: returns nil"
+  (evp "| n | n := 3. ^ [n <= 0] whileFalse: [n := n - 1]")
+  nil)
+
+;; ── 3. whileTrue (no arg) — body-less side-effect loop ──
+(st-test
+  "whileTrue without argument runs cond-only loop"
+  (evp
+    "| n decrement |
+     n := 5.
+     decrement := [n := n - 1. n > 0].
+     decrement whileTrue.
+     ^ n")
+  0)
+
+;; ── 4. whileFalse (no arg) ──
+(st-test
+  "whileFalse without argument"
+  (evp
+    "| n inc |
+     n := 0.
+     inc := [n := n + 1. n >= 3].
+     inc whileFalse.
+     ^ n")
+  3)
+
+;; ── 5. Cond block evaluated each iteration (not cached) ──
+(st-test
+  "whileTrue: re-evaluates cond on every iter"
+  (evp
+    "| n stop |
+     n := 0. stop := false.
+     [stop] whileFalse: [
+       n := n + 1.
+       n >= 4 ifTrue: [stop := true]].
+     ^ n")
+  4)
+
+;; ── 6. Body block sees outer locals ──
+(st-test
+  "whileTrue: body reads + writes captured locals"
+  (evp
+    "| acc i |
+     acc := 0. i := 1.
+     [i <= 10] whileTrue: [acc := acc + i. i := i + 1].
+     ^ acc")
+  55)
+
+;; ── 7. Nested while loops ──
+(st-test
+  "nested whileTrue: produces flat sum"
+  (evp
+    "| total i j |
+     total := 0. i := 0.
+     [i < 3] whileTrue: [
+       j := 0.
+       [j < 4] whileTrue: [total := total + 1. j := j + 1].
+       i := i + 1].
+     ^ total")
+  12)
+
+;; ── 8. ^ inside whileTrue: short-circuits the surrounding method ──
+(st-class-define! "WhileEscape" "Object" (list))
+(st-class-add-method! "WhileEscape" "firstOver:in:"
+  (st-parse-method
+    "firstOver: limit in: arr
+       | i |
+       i := 1.
+       [i <= arr size] whileTrue: [
+         (arr at: i) > limit ifTrue: [^ arr at: i].
+         i := i + 1].
+       ^ nil"))
+
+(st-test
+  "early ^ from whileTrue: body"
+  (evp "^ WhileEscape new firstOver: 5 in: #(1 3 5 7 9)")
+  7)
+
+(st-test
+  "whileTrue: completes when nothing matches"
+  (evp "^ WhileEscape new firstOver: 100 in: #(1 2 3)")
+  nil)
+
+;; ── 9. whileTrue: invocations independent across calls ──
+(st-class-define! "Counter2" "Object" (list "n"))
+(st-class-add-method! "Counter2" "init"
+  (st-parse-method "init n := 0. ^ self"))
+(st-class-add-method! "Counter2" "n"
+  (st-parse-method "n ^ n"))
+(st-class-add-method! "Counter2" "tick:"
+  (st-parse-method "tick: count [count > 0] whileTrue: [n := n + 1. count := count - 1]. ^ self"))
+
+(st-test
+  "instance state survives whileTrue: invocations"
+  (evp
+    "| c | c := Counter2 new init.
+     c tick: 3. c tick: 4.
+     ^ c n")
+  7)
+
+;; ── 10. Timing: whileTrue: on a never-true cond runs zero times ──
+(st-test
+  "whileTrue: with always-false cond"
+  (evp "| ran | ran := false. [false] whileTrue: [ran := true]. ^ ran")
+  false)
+
+(list st-test-pass st-test-fail)