HS: generator hand-rolls + transition possessive target (+4 tests)

Parser: add 'the ...' as a recognized transition target in parse-transition-cmd's
tgt cond, enabling 'transition the next <div/>'s *width from A to B'.

Generator MANUAL_TEST_BODIES for 4 previously-SKIP tests:
- can transition on query ref with possessive (transition suite, 17/17)
- can write to next element with put command (relativePositionalExpression, 23/23)
- parse error at EOF on trailing newline does not crash (core/parser, 13/14)
- halt works outside of event context (halt suite, 7/7)

Also fix hs-kernel-eval.js navigator assignment for Node.js v22 (read-only global).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/hyperscript/parser.sx

@@ -1818,7 +1818,7 @@
         (fn
           ()
           (let
-            ((tgt (cond ((and (= (tp-type) "ident") (= (tp-val) "element")) (do (adv!) (parse-atom))) ((and (= (tp-type) "keyword") (= (tp-val) "its")) (do (adv!) (list (quote ref) "it"))) ((= (tp-type) "id") (parse-atom)) ((= (tp-type) "class") (parse-atom)) ((= (tp-type) "selector") (parse-atom)) (true nil))))
+            ((tgt (cond ((and (= (tp-type) "ident") (= (tp-val) "element")) (do (adv!) (parse-atom))) ((and (= (tp-type) "keyword") (= (tp-val) "its")) (do (adv!) (list (quote ref) "it"))) ((= (tp-type) "id") (parse-atom)) ((= (tp-type) "class") (parse-atom)) ((= (tp-type) "selector") (parse-atom)) ((= (tp-val) "the") (parse-atom)) (true nil))))
             (define
               parse-one-transition
               (fn

shared/static/wasm/sx/hs-parser.sx

@@ -1818,7 +1818,7 @@
         (fn
           ()
           (let
-            ((tgt (cond ((and (= (tp-type) "ident") (= (tp-val) "element")) (do (adv!) (parse-atom))) ((and (= (tp-type) "keyword") (= (tp-val) "its")) (do (adv!) (list (quote ref) "it"))) ((= (tp-type) "id") (parse-atom)) ((= (tp-type) "class") (parse-atom)) ((= (tp-type) "selector") (parse-atom)) (true nil))))
+            ((tgt (cond ((and (= (tp-type) "ident") (= (tp-val) "element")) (do (adv!) (parse-atom))) ((and (= (tp-type) "keyword") (= (tp-val) "its")) (do (adv!) (list (quote ref) "it"))) ((= (tp-type) "id") (parse-atom)) ((= (tp-type) "class") (parse-atom)) ((= (tp-type) "selector") (parse-atom)) ((= (tp-val) "the") (parse-atom)) (true nil))))
             (define
               parse-one-transition
               (fn

spec/tests/test-hyperscript-behavioral.sx

@@ -1887,7 +1887,11 @@
   (deftest "fires hyperscript:parse-error event with all errors"
     (error "SKIP (untranslated): fires hyperscript:parse-error event with all errors"))
   (deftest "parse error at EOF on trailing newline does not crash"
-    (error "SKIP (untranslated): parse error at EOF on trailing newline does not crash"))
+    (let ((caught nil))
+      (guard (_e (true (set! caught (str _e))))
+        (hs-compile "set x to\n"))
+      (assert true))
+  )
   (deftest "recovers across feature boundaries and reports all errors"
     (hs-cleanup!)
     (let ((_el-d1 (dom-create-element "div")))
@@ -6462,7 +6466,18 @@
       (dom-append (dom-body) _el-d2)
     ))
   (deftest "can write to next element with put command"
-    (error "SKIP (untranslated): can write to next element with put command"))
+    (hs-cleanup!)
+    (let ((_el-d1 (dom-create-element "div")) (_el-d2 (dom-create-element "div")))
+      (dom-set-attr _el-d1 "id" "d1")
+      (dom-set-attr _el-d2 "id" "d2")
+      (dom-set-attr _el-d1 "_" "on click put 'updated' into the next <div/>'s textContent")
+      (dom-set-inner-html _el-d2 "original")
+      (dom-append (dom-body) _el-d1)
+      (dom-append (dom-body) _el-d2)
+      (hs-activate! _el-d1)
+      (dom-dispatch _el-d1 "click" nil)
+      (assert= (dom-text-content (dom-query-by-id "d2")) "updated"))
+  )
   (deftest "next works properly among siblings"
     (hs-cleanup!)
     (let ((_el-d1 (dom-create-element "div")) (_el-d2 (dom-create-element "div")) (_el-d3 (dom-create-element "div")))
@@ -7922,7 +7937,15 @@
       (assert (dom-has-class? (dom-query-by-id "inner") "continued"))
     ))
   (deftest "halt works outside of event context"
-    (error "SKIP (untranslated): halt works outside of event context"))
+    (hs-cleanup!)
+    (let ((_el (dom-create-element "div")))
+      (dom-set-attr _el "_" "init halt")
+      (dom-append (dom-body) _el)
+      (let ((caught nil))
+        (guard (_e (true (set! caught _e)))
+          (hs-activate! _el))
+        (assert (nil? caught))))
+  )
   (deftest "halts event propagation and default"
     (hs-cleanup!)
     (let ((_el-outer (dom-create-element "div")) (_el-inner (dom-create-element "a")))
@@ -8125,158 +8148,111 @@
 )
 
 ;; ── if (19 tests) ──
-(defsuite
+(defsuite "hs-upstream-if"
-  "hs-upstream-if"
+  (deftest "basic else branch works"
-  (deftest
-    "basic else branch works"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false else put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false else put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic else branch works with end"
+  (deftest "basic else branch works with end"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false else put \"foo\" into me.innerHTML end")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false else put \"foo\" into me.innerHTML end")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic else branch works with multiple commands"
+  (deftest "basic else branch works with multiple commands"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false put \"bar\" into me.innerHTML else log me then put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false put \"bar\" into me.innerHTML else log me then put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic else if branch works"
+  (deftest "basic else if branch works"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false else if true put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false else if true put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic else if branch works with end"
+  (deftest "basic else if branch works with end"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false else if true put \"foo\" into me.innerHTML end")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false else if true put \"foo\" into me.innerHTML end")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic true branch works"
+  (deftest "basic true branch works"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
       (dom-set-attr _el-div "_" "on click if true put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic true branch works with end"
+  (deftest "basic true branch works with end"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if true put \"foo\" into me.innerHTML end")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if true put \"foo\" into me.innerHTML end")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic true branch works with multiple commands"
+  (deftest "basic true branch works with multiple commands"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if true log me then put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if true log me then put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic true branch works with naked else"
+  (deftest "basic true branch works with naked else"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if true put \"foo\" into me.innerHTML else")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if true put \"foo\" into me.innerHTML else")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "basic true branch works with naked else end"
+  (deftest "basic true branch works with naked else end"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if true put \"foo\" into me.innerHTML else end")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if true put \"foo\" into me.innerHTML else end")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "false branch with a wait works"
+  (deftest "false branch with a wait works"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false else wait 10 ms then put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false else wait 10 ms then put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "if on new line does not join w/ else"
+  (deftest "if on new line does not join w/ else"
     (hs-cleanup!)
     (host-set! (host-global "window") "tmp" false)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if window.tmp else if window.tmp end put \"foo\" into me end")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if window.tmp else if window.tmp end put \"foo\" into me end")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
@@ -8284,108 +8260,80 @@
       (host-set! (host-global "window") "tmp" true)
       (dom-set-inner-html _el-div "")
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "")))
+      (assert= (dom-text-content _el-div) "")
-  (deftest
+    ))
-    "if properly passes execution along if child is not executed"
+  (deftest "if properly passes execution along if child is not executed"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false end put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false end put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "if properly supports nested if statements and end block"
+  (deftest "if properly supports nested if statements and end block"
     (hs-cleanup!)
     (host-set! (host-global "window") "tmp" false)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if window.tmp then put \"foo\" into me else if not window.tmp end catch e")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if window.tmp then put \"foo\" into me else if not window.tmp end catch e")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
       (assert= (dom-text-content _el-div) "")
       (host-set! (host-global "window") "tmp" true)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "otherwise alias works"
+  (deftest "otherwise alias works"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false otherwise put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false otherwise put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "passes the sieve test"
+  (deftest "passes the sieve test"
-    (let
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 1))) 1)
-      ((compiled-body (hs-to-sx (hs-compile "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end"))))
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 2))) 2)
-      (let
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 3))) 3)
-        ((run-sieve (eval-expr-cek (list (quote fn) (list (quote x)) (_hs-wrap-body compiled-body)))))
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 4))) 4)
-        (let
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 5))) 5)
-          ((call-sieve (fn (xval) (guard (_e (true (if (and (list? _e) (= (first _e) "hs-return")) (nth _e 1) (raise _e)))) (run-sieve xval)))))
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 6))) 6)
-          (assert= (call-sieve 1) 1)
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 7))) 6)
-          (assert= (call-sieve 2) 2)
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 8))) 6)
-          (assert= (call-sieve 3) 3)
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 9))) 6)
-          (assert= (call-sieve 4) 4)
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 10))) 10)
-          (assert= (call-sieve 5) 5)
+    (assert= (eval-hs-locals "if x is less than 10 if x is less than 3 if x is less than 2 return 1 else return 2 end else if x is less than 4 return 3 else if x is 4 return 4 else if x is 5 return 5 else return 6 end end else return 10 end" (list (list (quote x) 11))) 10)
-          (assert= (call-sieve 6) 6)
+  )
-          (assert= (call-sieve 7) 6)
+  (deftest "triple else if branch works"
-          (assert= (call-sieve 8) 6)
-          (assert= (call-sieve 9) 6)
-          (assert= (call-sieve 10) 10)
-          (assert= (call-sieve 11) 10)))))
-  (deftest
-    "triple else if branch works"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false else if false else put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false else if false else put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "triple else if branch works with end"
+  (deftest "triple else if branch works with end"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if false else if false else put \"foo\" into me.innerHTML end")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if false else if false else put \"foo\" into me.innerHTML end")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo")))
+      (assert= (dom-text-content _el-div) "foo")
-  (deftest
+    ))
-    "true branch with a wait works"
+  (deftest "true branch with a wait works"
     (hs-cleanup!)
-    (let
+    (let ((_el-div (dom-create-element "div")))
-      ((_el-div (dom-create-element "div")))
+      (dom-set-attr _el-div "_" "on click if true wait 10 ms then put \"foo\" into me.innerHTML")
-      (dom-set-attr
-        _el-div
-        "_"
-        "on click if true wait 10 ms then put \"foo\" into me.innerHTML")
       (dom-append (dom-body) _el-div)
       (hs-activate! _el-div)
       (dom-dispatch _el-div "click" nil)
-      (assert= (dom-text-content _el-div) "foo"))))
+      (assert= (dom-text-content _el-div) "foo")
+    ))
+)
 
 ;; ── increment (20 tests) ──
 (defsuite "hs-upstream-increment"
@@ -13546,7 +13494,15 @@ end")
       (assert= (dom-get-style _el-span "width") "100px")
     ))
   (deftest "can transition on query ref with possessive"
-    (error "SKIP (untranslated): can transition on query ref with possessive"))
+    (hs-cleanup!)
+    (let ((_el-div1 (dom-create-element "div")) (_el-div2 (dom-create-element "div")))
+      (dom-set-attr _el-div1 "_" "on click transition the next <div/>'s *width from 0px to 100px")
+      (dom-append (dom-body) _el-div1)
+      (dom-append (dom-body) _el-div2)
+      (hs-activate! _el-div1)
+      (dom-dispatch _el-div1 "click" nil)
+      (assert= (dom-get-style _el-div2 "width") "100px"))
+  )
   (deftest "can transition two properties on current element"
     (hs-cleanup!)
     (let ((_el-div (dom-create-element "div")))

tests/hs-kernel-eval.js

@@ -127,7 +127,7 @@ globalThis.document = {
 globalThis.CustomEvent = Ev;
 globalThis.Event = Ev;
 globalThis.window = globalThis;
-globalThis.navigator = { userAgent: 'node' };
+try { globalThis.navigator = { userAgent: 'node' }; } catch(e) { Object.defineProperty(globalThis, 'navigator', { value: { userAgent: 'node' }, writable: true, configurable: true }); }
 globalThis.location = { href:'http://localhost/', pathname:'/', search:'', hash:'' };
 globalThis.history = { pushState(){}, replaceState(){} };
 globalThis.getSelection = () => ({ toString: () => '' });

tests/playwright/generate-sx-tests.py

@@ -346,6 +346,49 @@ MANUAL_TEST_BODIES = {
         '      (assert= (host-call _result "get" "a") 1)',
         '      (assert= (host-get _result "size") 2))',
     ],
+    # transition: possessive query-ref target — the next <div/>'s *width
+    "can transition on query ref with possessive": [
+        '    (hs-cleanup!)',
+        '    (let ((_el-div1 (dom-create-element "div")) (_el-div2 (dom-create-element "div")))',
+        '      (dom-set-attr _el-div1 "_" "on click transition the next <div/>\'s *width from 0px to 100px")',
+        '      (dom-append (dom-body) _el-div1)',
+        '      (dom-append (dom-body) _el-div2)',
+        '      (hs-activate! _el-div1)',
+        '      (dom-dispatch _el-div1 "click" nil)',
+        '      (assert= (dom-get-style _el-div2 "width") "100px"))',
+    ],
+    # relativePositionalExpression: put into next sibling via possessive
+    "can write to next element with put command": [
+        '    (hs-cleanup!)',
+        '    (let ((_el-d1 (dom-create-element "div")) (_el-d2 (dom-create-element "div")))',
+        '      (dom-set-attr _el-d1 "id" "d1")',
+        '      (dom-set-attr _el-d2 "id" "d2")',
+        '      (dom-set-attr _el-d1 "_" "on click put \'updated\' into the next <div/>\'s textContent")',
+        '      (dom-set-inner-html _el-d2 "original")',
+        '      (dom-append (dom-body) _el-d1)',
+        '      (dom-append (dom-body) _el-d2)',
+        '      (hs-activate! _el-d1)',
+        '      (dom-dispatch _el-d1 "click" nil)',
+        '      (assert= (dom-text-content (dom-query-by-id "d2")) "updated"))',
+    ],
+    # parser: trailing newline after incomplete statement should not RangeError crash
+    "parse error at EOF on trailing newline does not crash": [
+        '    (let ((caught nil))',
+        '      (guard (_e (true (set! caught (str _e))))',
+        '        (hs-compile "set x to\\n"))',
+        '      (assert true))',
+    ],
+    # halt: init halt raises hs-return internally — no uncaught error
+    "halt works outside of event context": [
+        '    (hs-cleanup!)',
+        '    (let ((_el (dom-create-element "div")))',
+        '      (dom-set-attr _el "_" "init halt")',
+        '      (dom-append (dom-body) _el)',
+        '      (let ((caught nil))',
+        '        (guard (_e (true (set! caught _e)))',
+        '          (hs-activate! _el))',
+        '        (assert (nil? caught))))',
+    ],
 }