HS parser/compiler/runtime: fix 8 parse errors, add/remove arrays, return guard

Parser:
- `add VALUE to :var` → (add-value) for array append
- `remove VALUE from :var` → (remove-value) for array removal
- `toggle .foo for 10ms` → (toggle-class-for) with duration
- `append VALUE` without `to` → implicit target (it)
- `set {obj} on target` → (set-on) for object property spread
- `repeat in` body: remove spurious nil (body at index 3→2)
- Keywords followed by `(` parsed as function calls (fixes `increment()`)

Compiler:
- Handle add-value, remove-value, toggle-class-for, set-on AST nodes
- Local variables (`set :var`) use `define` instead of `set!`

Runtime:
- hs-add-to!: append value to list
- hs-remove-from!: filter value from list
- hs-set-on!: spread dict properties onto target
- `as String` for lists: comma-join (JS Array.toString compat)

Tests:
- eval-hs/eval-hs-with-me: guard for hs-return exceptions
  (return compiles to raise, needs handler to extract value)

Parse errors: 20→12 (8 fixed). Remaining: 6 embedded HTML quotes
(tokenizer), 6 transition template values `(expr)px`.

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

lib/hyperscript/compiler.sx

@@ -43,7 +43,7 @@
               ((= th (quote ref))
                 (list (quote set!) (make-symbol (nth target 1)) value))
               ((= th (quote local))
-                (list (quote set!) (make-symbol (nth target 1)) value))
+                (list (quote define) (make-symbol (nth target 1)) value))
               ((= th (quote me))
                 (list (quote dom-set-inner-html) (quote me) value))
               ((= th (quote it)) (list (quote set!) (quote it) value))
@@ -912,6 +912,20 @@
                       (nth ast 1)))))
               ((= head (quote remove-element))
                 (list (quote dom-remove) (hs-to-sx (nth ast 1))))
+              ((= head (quote add-value))
+                (let
+                  ((val (hs-to-sx (nth ast 1))) (tgt (nth ast 2)))
+                  (list
+                    (quote set!)
+                    (hs-to-sx tgt)
+                    (list (quote hs-add-to!) val (hs-to-sx tgt)))))
+              ((= head (quote remove-value))
+                (let
+                  ((val (hs-to-sx (nth ast 1))) (tgt (nth ast 2)))
+                  (list
+                    (quote set!)
+                    (hs-to-sx tgt)
+                    (list (quote hs-remove-from!) val (hs-to-sx tgt)))))
               ((= head (quote empty-target))
                 (list (quote hs-empty-target!) (hs-to-sx (nth ast 1))))
               ((= head (quote open-element))
@@ -946,6 +960,28 @@
                   (quote hs-toggle-class!)
                   (hs-to-sx (nth ast 2))
                   (nth ast 1)))
+              ((= head (quote toggle-class-for))
+                (list
+                  (quote do)
+                  (list
+                    (quote hs-toggle-class!)
+                    (hs-to-sx (nth ast 2))
+                    (nth ast 1))
+                  (list
+                    (quote perform)
+                    (list
+                      (quote list)
+                      (quote io-sleep)
+                      (hs-to-sx (nth ast 3))))
+                  (list
+                    (quote hs-toggle-class!)
+                    (hs-to-sx (nth ast 2))
+                    (nth ast 1))))
+              ((= head (quote set-on))
+                (list
+                  (quote hs-set-on!)
+                  (hs-to-sx (nth ast 1))
+                  (hs-to-sx (nth ast 2))))
               ((= head (quote toggle-between))
                 (list
                   (quote hs-toggle-between!)

lib/hyperscript/parser.sx

@@ -283,6 +283,12 @@
                             var-name
                             collection
                             (parse-expr))))))))
+              ((and (= typ "keyword") (> (len tokens) (+ p 1)) (= (get (nth tokens (+ p 1)) "type") "paren-open"))
+                (do
+                  (adv!)
+                  (let
+                    ((name val) (args (parse-call-args)))
+                    (list (quote call) (list (quote ref) name) args))))
               (true nil)))))
       (define
         parse-poss
@@ -805,7 +811,14 @@
                       (cons
                         (quote multi-add-class)
                         (cons tgt (cons cls extra-classes))))))))
-            nil)))
+            (let
+              ((value (parse-expr)))
+              (if
+                (match-kw "to")
+                (let
+                  ((tgt (parse-expr)))
+                  (list (quote add-value) value tgt))
+                nil)))))
       (define
         parse-remove-cmd
         (fn
@@ -870,8 +883,13 @@
                     (list (quote remove-css) props tgt)))))
             (true
               (let
-                ((target (parse-expr)))
+                ((value (parse-expr)))
-                (list (quote remove-element) target))))))
+                (if
+                  (match-kw "from")
+                  (let
+                    ((tgt (parse-expr)))
+                    (list (quote remove-value) value tgt))
+                  (list (quote remove-element) value)))))))
       (define
         parse-toggle-cmd
         (fn
@@ -897,7 +915,12 @@
                 ((cls (do (let ((v (tp-val))) (adv!) v))))
                 (let
                   ((tgt (parse-tgt-kw "on" (list (quote me)))))
-                  (list (quote toggle-class) cls tgt))))
+                  (if
+                    (match-kw "for")
+                    (let
+                      ((dur (parse-expr)))
+                      (list (quote toggle-class-for) cls tgt dur))
+                    (list (quote toggle-class) cls tgt)))))
             ((= (tp-type) "style")
               (let
                 ((prop (do (let ((v (tp-val))) (adv!) v))))
@@ -1006,8 +1029,14 @@
           ()
           (let
             ((tgt (parse-expr)))
-            (expect-kw! "to")
+            (cond
-            (let ((value (parse-expr))) (list (quote set!) tgt value)))))
+              ((match-kw "to")
+                (let ((value (parse-expr))) (list (quote set!) tgt value)))
+              ((match-kw "on")
+                (let
+                  ((target (parse-expr)))
+                  (list (quote set-on) tgt target)))
+              (true (error (str "Expected to/on at position " p)))))))
       (define
         parse-put-cmd
         (fn
@@ -1244,7 +1273,7 @@
                   (let
                     ((body (parse-cmd-list)))
                     (match-kw "end")
-                    (list (quote for) "it" collection nil body)))))
+                    (list (quote for) "it" collection body)))))
             (true
               (let
                 ((mode (cond ((match-kw "forever") (list (quote forever))) ((match-kw "while") (list (quote while) (parse-expr))) ((match-kw "until") (list (quote until) (parse-expr))) (true (let ((n (parse-expr))) (if (match-kw "times") (list (quote times) n) (list (quote forever))))))))
@@ -1464,10 +1493,12 @@
           ()
           (let
             ((value (parse-expr)))
-            (expect-kw! "to")
+            (if
-            (let
+              (match-kw "to")
-              ((target (parse-expr)))
+              (let
-              (list (quote append!) value target)))))
+                ((target (parse-expr)))
+                (list (quote append!) value target))
+              (list (quote append!) value (list (quote it)))))))
       (define
         parse-tell-cmd
         (fn

lib/hyperscript/runtime.sx

@@ -136,9 +136,35 @@
       ((= pos "end") (dom-insert-adjacent-html target "beforeend" value)))))
 
 ;; Find previous sibling matching a selector.
-(define hs-navigate! (fn (url) (perform (list (quote io-navigate) url))))
+(define
+  hs-add-to!
+  (fn
+    (value target)
+    (if
+      (list? target)
+      (append target (list value))
+      (host-call target "push" value))))
 
 ;; First element matching selector within a scope.
+(define
+  hs-remove-from!
+  (fn
+    (value target)
+    (if
+      (list? target)
+      (filter (fn (x) (not (= x value))) target)
+      (host-call target "splice" (host-call target "indexOf" value) 1))))
+
+;; Last element matching selector.
+(define
+  hs-set-on!
+  (fn
+    (props target)
+    (for-each (fn (k) (host-set! target k (get props k))) (keys props))))
+
+;; First/last within a specific scope.
+(define hs-navigate! (fn (url) (perform (list (quote io-navigate) url))))
+
 (define
   hs-scroll!
   (fn
@@ -151,7 +177,9 @@
           ((= position "bottom") (dict :block "end"))
           (true (dict :block "start")))))))
 
-;; Last element matching selector.
+;; ── Iteration ───────────────────────────────────────────────────
+
+;; Repeat a thunk N times.
 (define
   hs-halt!
   (fn
@@ -161,14 +189,19 @@
       (host-call event "preventDefault" (list))
       (when (= mode "event") (host-call event "stopPropagation" (list))))))
 
-;; First/last within a specific scope.
+;; Repeat forever (until break — relies on exception/continuation).
 (define hs-select! (fn (target) (host-call target "select" (list))))
 
+;; ── Fetch ───────────────────────────────────────────────────────
+
+;; Fetch a URL, parse response according to format.
+;; (hs-fetch url format) — format is "json" | "text" | "html"
 (define hs-reset! (fn (target) (host-call target "reset" (list))))
 
-;; ── Iteration ───────────────────────────────────────────────────
+;; ── Type coercion ───────────────────────────────────────────────
 
-;; Repeat a thunk N times.
+;; Coerce a value to a type by name.
+;; (hs-coerce value type-name) — type-name is "Int", "Float", "String", etc.
 (define
   hs-next
   (fn
@@ -188,7 +221,10 @@
               (true (find-next (dom-next-sibling el))))))
         (find-next sibling)))))
 
-;; Repeat forever (until break — relies on exception/continuation).
+;; ── Object creation ─────────────────────────────────────────────
+
+;; Make a new object of a given type.
+;; (hs-make type-name) — creates empty object/collection
 (define
   hs-previous
   (fn
@@ -208,26 +244,27 @@
               (true (find-prev (dom-get-prop el "previousElementSibling"))))))
         (find-prev sibling)))))
 
-;; ── Fetch ───────────────────────────────────────────────────────
+;; ── Behavior installation ───────────────────────────────────────
 
-;; Fetch a URL, parse response according to format.
+;; Install a behavior on an element.
-;; (hs-fetch url format) — format is "json" | "text" | "html"
+;; A behavior is a function that takes (me ...params) and sets up features.
+;; (hs-install behavior-fn me ...args)
 (define
   hs-query-all
   (fn (sel) (host-call (dom-body) "querySelectorAll" sel)))
 
-;; ── Type coercion ───────────────────────────────────────────────
+;; ── Measurement ─────────────────────────────────────────────────
 
-;; Coerce a value to a type by name.
+;; Measure an element's bounding rect, store as local variables.
-;; (hs-coerce value type-name) — type-name is "Int", "Float", "String", etc.
+;; Returns a dict with x, y, width, height, top, left, right, bottom.
 (define
   hs-query-first
   (fn (sel) (host-call (host-global "document") "querySelector" sel)))
 
-;; ── Object creation ─────────────────────────────────────────────
+;; ── Transition ──────────────────────────────────────────────────
 
-;; Make a new object of a given type.
+;; Transition a CSS property to a value, optionally with duration.
-;; (hs-make type-name) — creates empty object/collection
+;; (hs-transition target prop value duration)
 (define
   hs-query-last
   (fn
@@ -236,17 +273,8 @@
       ((all (dom-query-all (dom-body) sel)))
       (if (> (len all) 0) (nth all (- (len all) 1)) nil))))
 
-;; ── Behavior installation ───────────────────────────────────────
-
-;; Install a behavior on an element.
-;; A behavior is a function that takes (me ...params) and sets up features.
-;; (hs-install behavior-fn me ...args)
 (define hs-first (fn (scope sel) (dom-query-all scope sel)))
 
-;; ── Measurement ─────────────────────────────────────────────────
-
-;; Measure an element's bounding rect, store as local variables.
-;; Returns a dict with x, y, width, height, top, left, right, bottom.
 (define
   hs-last
   (fn
@@ -255,10 +283,6 @@
       ((all (dom-query-all scope sel)))
       (if (> (len all) 0) (nth all (- (len all) 1)) nil))))
 
-;; ── Transition ──────────────────────────────────────────────────
-
-;; Transition a CSS property to a value, optionally with duration.
-;; (hs-transition target prop value duration)
 (define
   hs-repeat-times
   (fn
@@ -296,7 +320,11 @@
       ((= type-name "Integer") (floor (+ value 0)))
       ((= type-name "Float") (+ value 0))
       ((= type-name "Number") (+ value 0))
-      ((= type-name "String") (str value))
+      ((= type-name "String")
+        (if
+          (list? value)
+          (join "," (map (fn (x) (str x)) value))
+          (str value)))
       ((= type-name "Bool") (not (hs-falsy? value)))
       ((= type-name "Boolean") (not (hs-falsy? value)))
       ((= type-name "Array") (if (list? value) value (list value)))
@@ -395,6 +423,10 @@
 
 (define hs-install (fn (behavior-fn) (behavior-fn me)))
 
+
+
+
+
 (define
   hs-measure
   (fn (target) (perform (list (quote io-measure) target))))
@@ -411,7 +443,8 @@
         (str prop " " (/ duration 1000) "s")))
     (dom-set-style target prop value)
     (when duration (hs-settle target))))
-
+;; ── Sandbox/test runtime additions ──────────────────────────────
+;; Property access — dot notation and .length
 (define
   hs-transition-from
   (fn
@@ -425,11 +458,7 @@
         (str prop " " (/ duration 1000) "s")))
     (dom-set-style target prop (str to-val))
     (when duration (hs-settle target))))
-
+;; DOM query stub — sandbox returns empty list
-
-
-
-
 (define
   hs-type-check
   (fn
@@ -449,34 +478,33 @@
             (= (host-typeof value) "element")
             (= (host-typeof value) "text")))
         (true (= (host-typeof value) (downcase type-name)))))))
-
+;; Method dispatch — obj.method(args)
 (define
   hs-type-check-strict
   (fn
     (value type-name)
     (if (nil? value) false (hs-type-check value type-name))))
-;; ── 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)))))
-;; Method dispatch — obj.method(args)
-(define
-  hs-starts-with-ic?
-  (fn (str prefix) (starts-with? (downcase str) (downcase prefix))))
 
 ;; ── 0.9.90 features ─────────────────────────────────────────────
 ;; beep! — debug logging, returns value unchanged
+(define
+  hs-strict-eq
+  (fn (a b) (and (= (type-of a) (type-of b)) (= a b))))
+;; Property-based is — check obj.key truthiness
+(define
+  hs-eq-ignore-case
+  (fn (a b) (= (downcase (str a)) (downcase (str b)))))
+;; Array slicing (inclusive both ends)
+(define
+  hs-starts-with-ic?
+  (fn (str prefix) (starts-with? (downcase str) (downcase prefix))))
+;; Collection: sorted by
 (define
   hs-contains-ignore-case?
   (fn
     (haystack needle)
     (contains? (downcase (str haystack)) (downcase (str needle)))))
-;; Property-based is — check obj.key truthiness
+;; Collection: sorted by descending
 (define
   hs-falsy?
   (fn
@@ -488,7 +516,7 @@
       ((and (list? v) (= (len v) 0)) true)
       ((= v 0) true)
       (true false))))
-;; Array slicing (inclusive both ends)
+;; Collection: split by
 (define
   hs-matches?
   (fn
@@ -499,7 +527,7 @@
       ((= (host-typeof target) "element")
         (if (string? pattern) (host-call target "matches" pattern) false))
       (true false))))
-;; Collection: sorted by
+;; Collection: joined by
 (define
   hs-contains?
   (fn
@@ -519,9 +547,9 @@
               true
               (hs-contains? (rest collection) item)))))
       (true false))))
-;; Collection: sorted by descending
+
 (define precedes? (fn (a b) (< (str a) (str b))))
-;; Collection: split by
+
 (define
   hs-empty?
   (fn
@@ -532,7 +560,7 @@
       ((list? v) (= (len v) 0))
       ((dict? v) (= (len (keys v)) 0))
       (true false))))
-;; Collection: joined by
+
 (define
   hs-empty-target!
   (fn

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

@@ -43,7 +43,7 @@
               ((= th (quote ref))
                 (list (quote set!) (make-symbol (nth target 1)) value))
               ((= th (quote local))
-                (list (quote set!) (make-symbol (nth target 1)) value))
+                (list (quote define) (make-symbol (nth target 1)) value))
               ((= th (quote me))
                 (list (quote dom-set-inner-html) (quote me) value))
               ((= th (quote it)) (list (quote set!) (quote it) value))
@@ -912,6 +912,20 @@
                       (nth ast 1)))))
               ((= head (quote remove-element))
                 (list (quote dom-remove) (hs-to-sx (nth ast 1))))
+              ((= head (quote add-value))
+                (let
+                  ((val (hs-to-sx (nth ast 1))) (tgt (nth ast 2)))
+                  (list
+                    (quote set!)
+                    (hs-to-sx tgt)
+                    (list (quote hs-add-to!) val (hs-to-sx tgt)))))
+              ((= head (quote remove-value))
+                (let
+                  ((val (hs-to-sx (nth ast 1))) (tgt (nth ast 2)))
+                  (list
+                    (quote set!)
+                    (hs-to-sx tgt)
+                    (list (quote hs-remove-from!) val (hs-to-sx tgt)))))
               ((= head (quote empty-target))
                 (list (quote hs-empty-target!) (hs-to-sx (nth ast 1))))
               ((= head (quote open-element))
@@ -946,6 +960,28 @@
                   (quote hs-toggle-class!)
                   (hs-to-sx (nth ast 2))
                   (nth ast 1)))
+              ((= head (quote toggle-class-for))
+                (list
+                  (quote do)
+                  (list
+                    (quote hs-toggle-class!)
+                    (hs-to-sx (nth ast 2))
+                    (nth ast 1))
+                  (list
+                    (quote perform)
+                    (list
+                      (quote list)
+                      (quote io-sleep)
+                      (hs-to-sx (nth ast 3))))
+                  (list
+                    (quote hs-toggle-class!)
+                    (hs-to-sx (nth ast 2))
+                    (nth ast 1))))
+              ((= head (quote set-on))
+                (list
+                  (quote hs-set-on!)
+                  (hs-to-sx (nth ast 1))
+                  (hs-to-sx (nth ast 2))))
               ((= head (quote toggle-between))
                 (list
                   (quote hs-toggle-between!)

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

@@ -283,6 +283,12 @@
                             var-name
                             collection
                             (parse-expr))))))))
+              ((and (= typ "keyword") (> (len tokens) (+ p 1)) (= (get (nth tokens (+ p 1)) "type") "paren-open"))
+                (do
+                  (adv!)
+                  (let
+                    ((name val) (args (parse-call-args)))
+                    (list (quote call) (list (quote ref) name) args))))
               (true nil)))))
       (define
         parse-poss
@@ -805,7 +811,14 @@
                       (cons
                         (quote multi-add-class)
                         (cons tgt (cons cls extra-classes))))))))
-            nil)))
+            (let
+              ((value (parse-expr)))
+              (if
+                (match-kw "to")
+                (let
+                  ((tgt (parse-expr)))
+                  (list (quote add-value) value tgt))
+                nil)))))
       (define
         parse-remove-cmd
         (fn
@@ -870,8 +883,13 @@
                     (list (quote remove-css) props tgt)))))
             (true
               (let
-                ((target (parse-expr)))
+                ((value (parse-expr)))
-                (list (quote remove-element) target))))))
+                (if
+                  (match-kw "from")
+                  (let
+                    ((tgt (parse-expr)))
+                    (list (quote remove-value) value tgt))
+                  (list (quote remove-element) value)))))))
       (define
         parse-toggle-cmd
         (fn
@@ -897,7 +915,12 @@
                 ((cls (do (let ((v (tp-val))) (adv!) v))))
                 (let
                   ((tgt (parse-tgt-kw "on" (list (quote me)))))
-                  (list (quote toggle-class) cls tgt))))
+                  (if
+                    (match-kw "for")
+                    (let
+                      ((dur (parse-expr)))
+                      (list (quote toggle-class-for) cls tgt dur))
+                    (list (quote toggle-class) cls tgt)))))
             ((= (tp-type) "style")
               (let
                 ((prop (do (let ((v (tp-val))) (adv!) v))))
@@ -1006,8 +1029,14 @@
           ()
           (let
             ((tgt (parse-expr)))
-            (expect-kw! "to")
+            (cond
-            (let ((value (parse-expr))) (list (quote set!) tgt value)))))
+              ((match-kw "to")
+                (let ((value (parse-expr))) (list (quote set!) tgt value)))
+              ((match-kw "on")
+                (let
+                  ((target (parse-expr)))
+                  (list (quote set-on) tgt target)))
+              (true (error (str "Expected to/on at position " p)))))))
       (define
         parse-put-cmd
         (fn
@@ -1244,7 +1273,7 @@
                   (let
                     ((body (parse-cmd-list)))
                     (match-kw "end")
-                    (list (quote for) "it" collection nil body)))))
+                    (list (quote for) "it" collection body)))))
             (true
               (let
                 ((mode (cond ((match-kw "forever") (list (quote forever))) ((match-kw "while") (list (quote while) (parse-expr))) ((match-kw "until") (list (quote until) (parse-expr))) (true (let ((n (parse-expr))) (if (match-kw "times") (list (quote times) n) (list (quote forever))))))))
@@ -1464,10 +1493,12 @@
           ()
           (let
             ((value (parse-expr)))
-            (expect-kw! "to")
+            (if
-            (let
+              (match-kw "to")
-              ((target (parse-expr)))
+              (let
-              (list (quote append!) value target)))))
+                ((target (parse-expr)))
+                (list (quote append!) value target))
+              (list (quote append!) value (list (quote it)))))))
       (define
         parse-tell-cmd
         (fn

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

@@ -136,9 +136,35 @@
       ((= pos "end") (dom-insert-adjacent-html target "beforeend" value)))))
 
 ;; Find previous sibling matching a selector.
-(define hs-navigate! (fn (url) (perform (list (quote io-navigate) url))))
+(define
+  hs-add-to!
+  (fn
+    (value target)
+    (if
+      (list? target)
+      (append target (list value))
+      (host-call target "push" value))))
 
 ;; First element matching selector within a scope.
+(define
+  hs-remove-from!
+  (fn
+    (value target)
+    (if
+      (list? target)
+      (filter (fn (x) (not (= x value))) target)
+      (host-call target "splice" (host-call target "indexOf" value) 1))))
+
+;; Last element matching selector.
+(define
+  hs-set-on!
+  (fn
+    (props target)
+    (for-each (fn (k) (host-set! target k (get props k))) (keys props))))
+
+;; First/last within a specific scope.
+(define hs-navigate! (fn (url) (perform (list (quote io-navigate) url))))
+
 (define
   hs-scroll!
   (fn
@@ -151,7 +177,9 @@
           ((= position "bottom") (dict :block "end"))
           (true (dict :block "start")))))))
 
-;; Last element matching selector.
+;; ── Iteration ───────────────────────────────────────────────────
+
+;; Repeat a thunk N times.
 (define
   hs-halt!
   (fn
@@ -161,14 +189,19 @@
       (host-call event "preventDefault" (list))
       (when (= mode "event") (host-call event "stopPropagation" (list))))))
 
-;; First/last within a specific scope.
+;; Repeat forever (until break — relies on exception/continuation).
 (define hs-select! (fn (target) (host-call target "select" (list))))
 
+;; ── Fetch ───────────────────────────────────────────────────────
+
+;; Fetch a URL, parse response according to format.
+;; (hs-fetch url format) — format is "json" | "text" | "html"
 (define hs-reset! (fn (target) (host-call target "reset" (list))))
 
-;; ── Iteration ───────────────────────────────────────────────────
+;; ── Type coercion ───────────────────────────────────────────────
 
-;; Repeat a thunk N times.
+;; Coerce a value to a type by name.
+;; (hs-coerce value type-name) — type-name is "Int", "Float", "String", etc.
 (define
   hs-next
   (fn
@@ -188,7 +221,10 @@
               (true (find-next (dom-next-sibling el))))))
         (find-next sibling)))))
 
-;; Repeat forever (until break — relies on exception/continuation).
+;; ── Object creation ─────────────────────────────────────────────
+
+;; Make a new object of a given type.
+;; (hs-make type-name) — creates empty object/collection
 (define
   hs-previous
   (fn
@@ -208,26 +244,27 @@
               (true (find-prev (dom-get-prop el "previousElementSibling"))))))
         (find-prev sibling)))))
 
-;; ── Fetch ───────────────────────────────────────────────────────
+;; ── Behavior installation ───────────────────────────────────────
 
-;; Fetch a URL, parse response according to format.
+;; Install a behavior on an element.
-;; (hs-fetch url format) — format is "json" | "text" | "html"
+;; A behavior is a function that takes (me ...params) and sets up features.
+;; (hs-install behavior-fn me ...args)
 (define
   hs-query-all
   (fn (sel) (host-call (dom-body) "querySelectorAll" sel)))
 
-;; ── Type coercion ───────────────────────────────────────────────
+;; ── Measurement ─────────────────────────────────────────────────
 
-;; Coerce a value to a type by name.
+;; Measure an element's bounding rect, store as local variables.
-;; (hs-coerce value type-name) — type-name is "Int", "Float", "String", etc.
+;; Returns a dict with x, y, width, height, top, left, right, bottom.
 (define
   hs-query-first
   (fn (sel) (host-call (host-global "document") "querySelector" sel)))
 
-;; ── Object creation ─────────────────────────────────────────────
+;; ── Transition ──────────────────────────────────────────────────
 
-;; Make a new object of a given type.
+;; Transition a CSS property to a value, optionally with duration.
-;; (hs-make type-name) — creates empty object/collection
+;; (hs-transition target prop value duration)
 (define
   hs-query-last
   (fn
@@ -236,17 +273,8 @@
       ((all (dom-query-all (dom-body) sel)))
       (if (> (len all) 0) (nth all (- (len all) 1)) nil))))
 
-;; ── Behavior installation ───────────────────────────────────────
-
-;; Install a behavior on an element.
-;; A behavior is a function that takes (me ...params) and sets up features.
-;; (hs-install behavior-fn me ...args)
 (define hs-first (fn (scope sel) (dom-query-all scope sel)))
 
-;; ── Measurement ─────────────────────────────────────────────────
-
-;; Measure an element's bounding rect, store as local variables.
-;; Returns a dict with x, y, width, height, top, left, right, bottom.
 (define
   hs-last
   (fn
@@ -255,10 +283,6 @@
       ((all (dom-query-all scope sel)))
       (if (> (len all) 0) (nth all (- (len all) 1)) nil))))
 
-;; ── Transition ──────────────────────────────────────────────────
-
-;; Transition a CSS property to a value, optionally with duration.
-;; (hs-transition target prop value duration)
 (define
   hs-repeat-times
   (fn
@@ -296,7 +320,11 @@
       ((= type-name "Integer") (floor (+ value 0)))
       ((= type-name "Float") (+ value 0))
       ((= type-name "Number") (+ value 0))
-      ((= type-name "String") (str value))
+      ((= type-name "String")
+        (if
+          (list? value)
+          (join "," (map (fn (x) (str x)) value))
+          (str value)))
       ((= type-name "Bool") (not (hs-falsy? value)))
       ((= type-name "Boolean") (not (hs-falsy? value)))
       ((= type-name "Array") (if (list? value) value (list value)))
@@ -395,6 +423,10 @@
 
 (define hs-install (fn (behavior-fn) (behavior-fn me)))
 
+
+
+
+
 (define
   hs-measure
   (fn (target) (perform (list (quote io-measure) target))))
@@ -411,7 +443,8 @@
         (str prop " " (/ duration 1000) "s")))
     (dom-set-style target prop value)
     (when duration (hs-settle target))))
-
+;; ── Sandbox/test runtime additions ──────────────────────────────
+;; Property access — dot notation and .length
 (define
   hs-transition-from
   (fn
@@ -425,11 +458,7 @@
         (str prop " " (/ duration 1000) "s")))
     (dom-set-style target prop (str to-val))
     (when duration (hs-settle target))))
-
+;; DOM query stub — sandbox returns empty list
-
-
-
-
 (define
   hs-type-check
   (fn
@@ -449,34 +478,33 @@
             (= (host-typeof value) "element")
             (= (host-typeof value) "text")))
         (true (= (host-typeof value) (downcase type-name)))))))
-
+;; Method dispatch — obj.method(args)
 (define
   hs-type-check-strict
   (fn
     (value type-name)
     (if (nil? value) false (hs-type-check value type-name))))
-;; ── 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)))))
-;; Method dispatch — obj.method(args)
-(define
-  hs-starts-with-ic?
-  (fn (str prefix) (starts-with? (downcase str) (downcase prefix))))
 
 ;; ── 0.9.90 features ─────────────────────────────────────────────
 ;; beep! — debug logging, returns value unchanged
+(define
+  hs-strict-eq
+  (fn (a b) (and (= (type-of a) (type-of b)) (= a b))))
+;; Property-based is — check obj.key truthiness
+(define
+  hs-eq-ignore-case
+  (fn (a b) (= (downcase (str a)) (downcase (str b)))))
+;; Array slicing (inclusive both ends)
+(define
+  hs-starts-with-ic?
+  (fn (str prefix) (starts-with? (downcase str) (downcase prefix))))
+;; Collection: sorted by
 (define
   hs-contains-ignore-case?
   (fn
     (haystack needle)
     (contains? (downcase (str haystack)) (downcase (str needle)))))
-;; Property-based is — check obj.key truthiness
+;; Collection: sorted by descending
 (define
   hs-falsy?
   (fn
@@ -488,7 +516,7 @@
       ((and (list? v) (= (len v) 0)) true)
       ((= v 0) true)
       (true false))))
-;; Array slicing (inclusive both ends)
+;; Collection: split by
 (define
   hs-matches?
   (fn
@@ -499,7 +527,7 @@
       ((= (host-typeof target) "element")
         (if (string? pattern) (host-call target "matches" pattern) false))
       (true false))))
-;; Collection: sorted by
+;; Collection: joined by
 (define
   hs-contains?
   (fn
@@ -519,9 +547,9 @@
               true
               (hs-contains? (rest collection) item)))))
       (true false))))
-;; Collection: sorted by descending
+
 (define precedes? (fn (a b) (< (str a) (str b))))
-;; Collection: split by
+
 (define
   hs-empty?
   (fn
@@ -532,7 +560,7 @@
       ((list? v) (= (len v) 0))
       ((dict? v) (= (len (keys v)) 0))
       (true false))))
-;; Collection: joined by
+
 (define
   hs-empty-target!
   (fn