HS: return/guard, repeat while/until, if-then fix, script extraction

Parser: if-then consumes 'then' keyword before parsing then-body.
Compiler: return→raise, def→guard, repeat while/until dispatch.
Runtime: hs-repeat-while, hs-repeat-until.
Test gen: script block extraction for def functions.
repeat suite: 10→13/30.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/hyperscript/runtime.sx

@@ -275,6 +275,12 @@
     (define do-forever (fn () (thunk) (do-forever)))
     (do-forever)))
 
+(define
+  hs-repeat-while
+  (fn
+    (cond-fn thunk)
+    (when (cond-fn) (thunk) (hs-repeat-while cond-fn thunk))))
+
 (define
   hs-fetch
   (fn
@@ -426,6 +432,10 @@
     (dom-set-style target prop (str to-val))
     (when duration (hs-settle target))))
 
+
+
+
+
 (define
   hs-type-check
   (fn
@@ -446,37 +456,33 @@
             (= (host-typeof value) "text")))
         (true (= (host-typeof value) (downcase type-name)))))))
 
-
-
-
-
 (define
   hs-type-check-strict
   (fn
     (value type-name)
     (if (nil? value) false (hs-type-check value type-name))))
-
-(define
-  hs-strict-eq
-  (fn (a b) (and (= (type-of a) (type-of b)) (= a b))))
 ;; ── Sandbox/test runtime additions ──────────────────────────────
 ;; Property access — dot notation and .length
+(define
+  hs-strict-eq
+  (fn (a b) (and (= (type-of a) (type-of b)) (= a b))))
+;; DOM query stub — sandbox returns empty list
 (define
   hs-eq-ignore-case
   (fn (a b) (= (downcase (str a)) (downcase (str b)))))
-;; DOM query stub — sandbox returns empty list
+;; Method dispatch — obj.method(args)
 (define
   hs-starts-with-ic?
   (fn (str prefix) (starts-with? (downcase str) (downcase prefix))))
-;; Method dispatch — obj.method(args)
+
+;; ── 0.9.90 features ─────────────────────────────────────────────
+;; beep! — debug logging, returns value unchanged
 (define
   hs-contains-ignore-case?
   (fn
     (haystack needle)
     (contains? (downcase (str haystack)) (downcase (str needle)))))
-
-;; ── 0.9.90 features ─────────────────────────────────────────────
-;; beep! — debug logging, returns value unchanged
+;; Property-based is — check obj.key truthiness
 (define
   hs-falsy?
   (fn
@@ -488,7 +494,7 @@
       ((and (list? v) (= (len v) 0)) true)
       ((= v 0) true)
       (true false))))
-;; Property-based is — check obj.key truthiness
+;; Array slicing (inclusive both ends)
 (define
   hs-matches?
   (fn
@@ -499,7 +505,7 @@
       ((= (host-typeof target) "element")
         (if (string? pattern) (host-call target "matches" pattern) false))
       (true false))))
-;; Array slicing (inclusive both ends)
+;; Collection: sorted by
 (define
   hs-contains?
   (fn
@@ -519,9 +525,9 @@
               true
               (hs-contains? (rest collection) item)))))
       (true false))))
-;; Collection: sorted by
-(define precedes? (fn (a b) (< (str a) (str b))))
 ;; Collection: sorted by descending
+(define precedes? (fn (a b) (< (str a) (str b))))
+;; Collection: split by
 (define
   hs-empty?
   (fn
@@ -532,7 +538,7 @@
       ((list? v) (= (len v) 0))
       ((dict? v) (= (len (keys v)) 0))
       (true false))))
-;; Collection: split by
+;; Collection: joined by
 (define
   hs-empty-target!
   (fn
@@ -557,7 +563,7 @@
                 ((children (host-call target "querySelectorAll" "input, textarea, select")))
                 (for-each (fn (el) (hs-empty-target! el)) children)))
             (true (dom-set-inner-html target ""))))))))
-;; Collection: joined by
+
 (define
   hs-open!
   (fn