HS: remove bare @attr, set X @attr, JSON clean, FormEncoded, HTML join

- parser remove/set: accept bare @attr (not just [@attr])
- parser set: wrap tgt as (attr name tgt) when @attr follows target
- runtime: hs-json-stringify walks sx-dict/list to emit plain JSON
  (strips _type key which leaked via JSON.stringify)
- hs-coerce JSON / JSONString: use hs-json-stringify
- hs-coerce FormEncoded: dict → k=v&... (list values repeat key)
- hs-coerce HTML: join list elements; element → outerHTML

+4 tests (button query in form, JSONString value, array→HTML,
form | JSONString now fails only on key order).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/hyperscript/compiler.sx

@@ -18,7 +18,17 @@
         (target value)
         (if
           (not (list? target))
-          (list (quote set!) target value)
+          (if
+            (= target (quote the-result))
+            (list
+              (quote let)
+              (list (list (quote __hs-r) value))
+              (list
+                (quote begin)
+                (list (quote set!) (quote the-result) (quote __hs-r))
+                (list (quote set!) (quote it) (quote __hs-r))
+                (quote __hs-r)))
+            (list (quote set!) target value))
           (let
             ((th (first target)))
             (cond
@@ -1169,15 +1179,71 @@
                   (let
                     ((tgt-expr (cond ((and (list? raw-tgt) (= (first raw-tgt) (quote query))) (list (quote hs-query-all) (nth raw-tgt 1))) ((and (list? raw-tgt) (= (first raw-tgt) (quote in?)) (list? (nth raw-tgt 1)) (= (first (nth raw-tgt 1)) (quote query))) (list (quote host-call) (hs-to-sx (nth raw-tgt 2)) "querySelectorAll" (nth (nth raw-tgt 1) 1))) (true (hs-to-sx raw-tgt)))))
                     (list
-                      (quote for-each)
+                      (quote let)
                       (list
-                        (quote fn)
-                        (list (quote it))
                         (list
-                          (quote when)
+                          (quote __hs-matched)
-                          (hs-to-sx when-cond)
+                          (list
-                          (list (quote dom-add-class) (quote it) cls)))
+                            (quote filter)
-                      tgt-expr))))
+                            (list
+                              (quote fn)
+                              (list (quote it))
+                              (hs-to-sx when-cond))
+                            tgt-expr)))
+                      (list
+                        (quote begin)
+                        (list
+                          (quote set!)
+                          (quote the-result)
+                          (quote __hs-matched))
+                        (list (quote set!) (quote it) (quote __hs-matched))
+                        (list
+                          (quote for-each)
+                          (list
+                            (quote fn)
+                            (list (quote it))
+                            (list (quote dom-add-class) (quote it) cls))
+                          (quote __hs-matched))
+                        (quote __hs-matched))))))
+              ((= head (quote add-attr-when))
+                (let
+                  ((attr-name (nth ast 1))
+                    (attr-val (hs-to-sx (nth ast 2)))
+                    (raw-tgt (nth ast 3))
+                    (when-cond (nth ast 4)))
+                  (let
+                    ((tgt-expr (cond ((and (list? raw-tgt) (= (first raw-tgt) (quote query))) (list (quote hs-query-all) (nth raw-tgt 1))) (true (hs-to-sx raw-tgt)))))
+                    (list
+                      (quote let)
+                      (list
+                        (list
+                          (quote __hs-matched)
+                          (list
+                            (quote filter)
+                            (list
+                              (quote fn)
+                              (list (quote it))
+                              (hs-to-sx when-cond))
+                            tgt-expr)))
+                      (list
+                        (quote begin)
+                        (list
+                          (quote set!)
+                          (quote the-result)
+                          (quote __hs-matched))
+                        (list (quote set!) (quote it) (quote __hs-matched))
+                        (list
+                          (quote for-each)
+                          (list
+                            (quote fn)
+                            (list (quote it))
+                            (list
+                              (quote hs-set-attr!)
+                              (quote it)
+                              attr-name
+                              attr-val))
+                          (quote __hs-matched))
+                        (quote __hs-matched))))))
               ((= head (quote multi-remove-class))
                 (let
                   ((target (hs-to-sx (nth ast 1)))
@@ -1598,11 +1664,17 @@
               ((= head (quote append!))
                 (let
                   ((tgt (hs-to-sx (nth ast 2)))
-                    (val (hs-to-sx (nth ast 1))))
+                    (val (hs-to-sx (nth ast 1)))
-                  (if
+                    (raw-tgt (nth ast 2)))
-                    (symbol? tgt)
+                  (cond
-                    (list (quote set!) tgt (list (quote hs-append) tgt val))
+                    ((symbol? tgt)
-                    (list (quote hs-append!) val tgt))))
+                      (list
+                        (quote set!)
+                        tgt
+                        (list (quote hs-append) tgt val)))
+                    ((and (list? raw-tgt) (or (= (first raw-tgt) (quote local)) (= (first raw-tgt) (quote ref))))
+                      (emit-set raw-tgt (list (quote hs-append) tgt val)))
+                    (true (list (quote hs-append!) val tgt)))))
               ((= head (quote tell))
                 (let
                   ((tgt (hs-to-sx (nth ast 1))))

lib/hyperscript/parser.sx

@@ -954,7 +954,35 @@
                     (when (= (tp-type) "bracket-close") (adv!))
                     (let
                       ((tgt (parse-tgt-kw "to" (list (quote me)))))
-                      (list (quote add-attr) attr-name attr-val tgt))))))
+                      (let
+                        ((when-clause (if (match-kw "when") (parse-expr) nil)))
+                        (if
+                          when-clause
+                          (list
+                            (quote add-attr-when)
+                            attr-name
+                            attr-val
+                            tgt
+                            when-clause)
+                          (list (quote add-attr) attr-name attr-val tgt))))))))
+            ((= (tp-type) "attr")
+              (let
+                ((attr-name (get (adv!) "value")))
+                (let
+                  ((attr-val (if (and (= (tp-type) "op") (= (tp-val) "=")) (do (adv!) (parse-expr)) "")))
+                  (let
+                    ((tgt (if (match-kw "to") (parse-expr) (list (quote me)))))
+                    (let
+                      ((when-clause (if (match-kw "when") (parse-expr) nil)))
+                      (if
+                        when-clause
+                        (list
+                          (quote add-attr-when)
+                          attr-name
+                          attr-val
+                          tgt
+                          when-clause)
+                        (list (quote add-attr) attr-name attr-val tgt)))))))
             (true
               (let
                 ((value (parse-expr)))
@@ -991,6 +1019,12 @@
                     (cons
                       (quote multi-remove-class)
                       (cons tgt (cons cls extra-classes)))))))
+            ((= (tp-type) "attr")
+              (let
+                ((attr-name (get (adv!) "value")))
+                (let
+                  ((tgt (if (match-kw "from") (parse-expr) (list (quote me)))))
+                  (list (quote remove-attr) attr-name tgt))))
             ((and (= (tp-type) "bracket-open") (= (tp-val) "["))
               (do
                 (adv!)
@@ -1276,20 +1310,24 @@
         (fn
           ()
           (let
-            ((tgt (cond ((and (= (tp-type) "ident") (or (= (tp-val) "element") (= (tp-val) "global") (= (tp-val) "local"))) (do (adv!) (parse-expr))) (true (parse-expr)))))
+            ((tgt-raw (cond ((and (= (tp-type) "ident") (or (= (tp-val) "element") (= (tp-val) "global") (= (tp-val) "local"))) (do (adv!) (parse-expr))) (true (parse-expr)))))
-            (cond
+            (let
-              ((match-kw "to")
+              ((tgt (if (= (tp-type) "attr") (let ((attr-name (get (adv!) "value"))) (list (quote attr) attr-name tgt-raw)) tgt-raw)))
-                (let ((value (parse-expr))) (list (quote set!) tgt value)))
+              (cond
-              ((match-kw "on")
+                ((match-kw "to")
-                (let
+                  (let
-                  ((target (parse-expr)))
+                    ((value (parse-expr)))
-                  (if
+                    (list (quote set!) tgt value)))
-                    (match-kw "to")
+                ((match-kw "on")
-                    (let
+                  (let
-                      ((value (parse-expr)))
+                    ((target (parse-expr)))
-                      (list (quote set-on!) tgt target value))
+                    (if
-                    (list (quote set-on) tgt target))))
+                      (match-kw "to")
-              (true (error (str "Expected to/on at position " p)))))))
+                      (let
+                        ((value (parse-expr)))
+                        (list (quote set-on!) tgt target value))
+                      (list (quote set-on) tgt target))))
+                (true (error (str "Expected to/on at position " p))))))))
       (define
         parse-put-cmd
         (fn

lib/hyperscript/runtime.sx

@@ -294,10 +294,13 @@
   hs-add-to!
   (fn
     (value target)
-    (if
+    (cond
-      (list? target)
+      ((list? target)
-      (append target (list value))
+        (if
-      (host-call target "push" value))))
+          (some (fn (x) (= x value)) target)
+          target
+          (append target (list value))))
+      (true (do (host-call target "push" value) target)))))
 
 ;; First/last within a specific scope.
 (define
@@ -664,7 +667,11 @@
       (cond
         ((nil? target) value)
         ((string? target) (str target value))
-        ((list? target) (append target (list value)))
+        ((list? target)
+          (if
+            (some (fn (x) (= x value)) target)
+            target
+            (append target (list value))))
         ((hs-element? target)
           (do
             (dom-insert-adjacent-html target "beforeend" (str value))
@@ -688,6 +695,61 @@
       ((fmt (cond ((nil? format) "text") ((or (= format "JSON") (= format "json") (= format "Object") (= format "object")) "json") ((or (= format "HTML") (= format "html")) "html") ((or (= format "Response") (= format "response")) "response") ((or (= format "Text") (= format "text")) "text") (true format))))
       (perform (list "io-fetch" url fmt)))))
 ;; Array slicing (inclusive both ends)
+(define
+  hs-json-escape
+  (fn
+    (s)
+    (str
+      "\""
+      (let
+        ((out "") (i 0) (n (string-length s)))
+        (define
+          walk
+          (fn
+            ()
+            (when
+              (< i n)
+              (let
+                ((c (substring s i (+ i 1))))
+                (set!
+                  out
+                  (cond
+                    ((= c "\\") (str out "\\\\"))
+                    ((= c "\"") (str out "\\\""))
+                    ((= c "\n") (str out "\\n"))
+                    ((= c "\r") (str out "\\r"))
+                    ((= c "\t") (str out "\\t"))
+                    (true (str out c))))
+                (set! i (+ i 1))
+                (walk)))))
+        (walk)
+        out)
+      "\"")))
+;; Collection: sorted by
+(define
+  hs-json-stringify
+  (fn
+    (v)
+    (cond
+      ((nil? v) "null")
+      ((= v true) "true")
+      ((= v false) "false")
+      ((number? v) (str v))
+      ((string? v) (hs-json-escape v))
+      ((list? v) (str "[" (join "," (map hs-json-stringify v)) "]"))
+      ((dict? v)
+        (str
+          "{"
+          (join
+            ","
+            (map
+              (fn
+                (k)
+                (str (hs-json-escape k) ":" (hs-json-stringify (get v k))))
+              (keys v)))
+          "}"))
+      (true (hs-json-escape (str v))))))
+;; Collection: sorted by descending
 (define
   hs-coerce
   (fn
@@ -705,19 +767,39 @@
       ((= type-name "Bool") (not (hs-falsy? value)))
       ((= type-name "Boolean") (not (hs-falsy? value)))
       ((= type-name "Array") (if (list? value) value (list value)))
-      ((= type-name "HTML") (str value))
+      ((= type-name "HTML")
+        (cond
+          ((list? value) (join "" (map (fn (x) (str x)) value)))
+          ((hs-element? value) (host-get value "outerHTML"))
+          (true (str value))))
       ((= type-name "JSON")
         (cond
           ((string? value) (guard (_e (true value)) (json-parse value)))
-          ((dict? value) (json-stringify value))
+          ((dict? value) (hs-json-stringify value))
-          ((list? value) (json-stringify value))
+          ((list? value) (hs-json-stringify value))
           (true value)))
       ((= type-name "Object")
         (if
           (string? value)
           (guard (_e (true value)) (json-parse value))
           value))
-      ((= type-name "JSONString") (json-stringify value))
+      ((= type-name "JSONString") (hs-json-stringify value))
+      ((= type-name "FormEncoded")
+        (if
+          (dict? value)
+          (join
+            "&"
+            (map
+              (fn
+                (k)
+                (let
+                  ((v (get value k)))
+                  (if
+                    (list? v)
+                    (join "&" (map (fn (item) (str k "=" item)) v))
+                    (str k "=" v))))
+              (keys value)))
+          (str value)))
       ((or (= type-name "Fixed") (= type-name "Fixed:") (starts-with? type-name "Fixed:"))
         (let
           ((digits (if (> (string-length type-name) 6) (+ (substring type-name 6 (string-length type-name)) 0) 0))
@@ -774,7 +856,7 @@
           (map (fn (k) (list k (get value k))) (keys value))
           value))
       (true value))))
-;; Collection: sorted by
+;; Collection: split by
 (define
   hs-gather-form-nodes
   (fn
@@ -808,11 +890,11 @@
                       (each 0)))))))))
       (walk root)
       acc)))
-;; Collection: sorted by descending
+;; Collection: joined by
 (define
   hs-values-from-nodes
   (fn (nodes) (reduce hs-values-absorb (dict) nodes)))
-;; Collection: split by
+
 (define
   hs-value-of-node
   (fn
@@ -828,7 +910,7 @@
         ((or (= typ "checkbox") (= typ "radio"))
           (if (host-get node "checked") (host-get node "value") nil))
         (true (host-get node "value"))))))
-;; Collection: joined by
+
 (define
   hs-select-multi-values
   (fn

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

@@ -18,7 +18,17 @@
         (target value)
         (if
           (not (list? target))
-          (list (quote set!) target value)
+          (if
+            (= target (quote the-result))
+            (list
+              (quote let)
+              (list (list (quote __hs-r) value))
+              (list
+                (quote begin)
+                (list (quote set!) (quote the-result) (quote __hs-r))
+                (list (quote set!) (quote it) (quote __hs-r))
+                (quote __hs-r)))
+            (list (quote set!) target value))
           (let
             ((th (first target)))
             (cond
@@ -1169,15 +1179,71 @@
                   (let
                     ((tgt-expr (cond ((and (list? raw-tgt) (= (first raw-tgt) (quote query))) (list (quote hs-query-all) (nth raw-tgt 1))) ((and (list? raw-tgt) (= (first raw-tgt) (quote in?)) (list? (nth raw-tgt 1)) (= (first (nth raw-tgt 1)) (quote query))) (list (quote host-call) (hs-to-sx (nth raw-tgt 2)) "querySelectorAll" (nth (nth raw-tgt 1) 1))) (true (hs-to-sx raw-tgt)))))
                     (list
-                      (quote for-each)
+                      (quote let)
                       (list
-                        (quote fn)
-                        (list (quote it))
                         (list
-                          (quote when)
+                          (quote __hs-matched)
-                          (hs-to-sx when-cond)
+                          (list
-                          (list (quote dom-add-class) (quote it) cls)))
+                            (quote filter)
-                      tgt-expr))))
+                            (list
+                              (quote fn)
+                              (list (quote it))
+                              (hs-to-sx when-cond))
+                            tgt-expr)))
+                      (list
+                        (quote begin)
+                        (list
+                          (quote set!)
+                          (quote the-result)
+                          (quote __hs-matched))
+                        (list (quote set!) (quote it) (quote __hs-matched))
+                        (list
+                          (quote for-each)
+                          (list
+                            (quote fn)
+                            (list (quote it))
+                            (list (quote dom-add-class) (quote it) cls))
+                          (quote __hs-matched))
+                        (quote __hs-matched))))))
+              ((= head (quote add-attr-when))
+                (let
+                  ((attr-name (nth ast 1))
+                    (attr-val (hs-to-sx (nth ast 2)))
+                    (raw-tgt (nth ast 3))
+                    (when-cond (nth ast 4)))
+                  (let
+                    ((tgt-expr (cond ((and (list? raw-tgt) (= (first raw-tgt) (quote query))) (list (quote hs-query-all) (nth raw-tgt 1))) (true (hs-to-sx raw-tgt)))))
+                    (list
+                      (quote let)
+                      (list
+                        (list
+                          (quote __hs-matched)
+                          (list
+                            (quote filter)
+                            (list
+                              (quote fn)
+                              (list (quote it))
+                              (hs-to-sx when-cond))
+                            tgt-expr)))
+                      (list
+                        (quote begin)
+                        (list
+                          (quote set!)
+                          (quote the-result)
+                          (quote __hs-matched))
+                        (list (quote set!) (quote it) (quote __hs-matched))
+                        (list
+                          (quote for-each)
+                          (list
+                            (quote fn)
+                            (list (quote it))
+                            (list
+                              (quote hs-set-attr!)
+                              (quote it)
+                              attr-name
+                              attr-val))
+                          (quote __hs-matched))
+                        (quote __hs-matched))))))
               ((= head (quote multi-remove-class))
                 (let
                   ((target (hs-to-sx (nth ast 1)))
@@ -1598,11 +1664,17 @@
               ((= head (quote append!))
                 (let
                   ((tgt (hs-to-sx (nth ast 2)))
-                    (val (hs-to-sx (nth ast 1))))
+                    (val (hs-to-sx (nth ast 1)))
-                  (if
+                    (raw-tgt (nth ast 2)))
-                    (symbol? tgt)
+                  (cond
-                    (list (quote set!) tgt (list (quote hs-append) tgt val))
+                    ((symbol? tgt)
-                    (list (quote hs-append!) val tgt))))
+                      (list
+                        (quote set!)
+                        tgt
+                        (list (quote hs-append) tgt val)))
+                    ((and (list? raw-tgt) (or (= (first raw-tgt) (quote local)) (= (first raw-tgt) (quote ref))))
+                      (emit-set raw-tgt (list (quote hs-append) tgt val)))
+                    (true (list (quote hs-append!) val tgt)))))
               ((= head (quote tell))
                 (let
                   ((tgt (hs-to-sx (nth ast 1))))

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

@@ -954,7 +954,35 @@
                     (when (= (tp-type) "bracket-close") (adv!))
                     (let
                       ((tgt (parse-tgt-kw "to" (list (quote me)))))
-                      (list (quote add-attr) attr-name attr-val tgt))))))
+                      (let
+                        ((when-clause (if (match-kw "when") (parse-expr) nil)))
+                        (if
+                          when-clause
+                          (list
+                            (quote add-attr-when)
+                            attr-name
+                            attr-val
+                            tgt
+                            when-clause)
+                          (list (quote add-attr) attr-name attr-val tgt))))))))
+            ((= (tp-type) "attr")
+              (let
+                ((attr-name (get (adv!) "value")))
+                (let
+                  ((attr-val (if (and (= (tp-type) "op") (= (tp-val) "=")) (do (adv!) (parse-expr)) "")))
+                  (let
+                    ((tgt (if (match-kw "to") (parse-expr) (list (quote me)))))
+                    (let
+                      ((when-clause (if (match-kw "when") (parse-expr) nil)))
+                      (if
+                        when-clause
+                        (list
+                          (quote add-attr-when)
+                          attr-name
+                          attr-val
+                          tgt
+                          when-clause)
+                        (list (quote add-attr) attr-name attr-val tgt)))))))
             (true
               (let
                 ((value (parse-expr)))
@@ -991,6 +1019,12 @@
                     (cons
                       (quote multi-remove-class)
                       (cons tgt (cons cls extra-classes)))))))
+            ((= (tp-type) "attr")
+              (let
+                ((attr-name (get (adv!) "value")))
+                (let
+                  ((tgt (if (match-kw "from") (parse-expr) (list (quote me)))))
+                  (list (quote remove-attr) attr-name tgt))))
             ((and (= (tp-type) "bracket-open") (= (tp-val) "["))
               (do
                 (adv!)
@@ -1276,20 +1310,24 @@
         (fn
           ()
           (let
-            ((tgt (cond ((and (= (tp-type) "ident") (or (= (tp-val) "element") (= (tp-val) "global") (= (tp-val) "local"))) (do (adv!) (parse-expr))) (true (parse-expr)))))
+            ((tgt-raw (cond ((and (= (tp-type) "ident") (or (= (tp-val) "element") (= (tp-val) "global") (= (tp-val) "local"))) (do (adv!) (parse-expr))) (true (parse-expr)))))
-            (cond
+            (let
-              ((match-kw "to")
+              ((tgt (if (= (tp-type) "attr") (let ((attr-name (get (adv!) "value"))) (list (quote attr) attr-name tgt-raw)) tgt-raw)))
-                (let ((value (parse-expr))) (list (quote set!) tgt value)))
+              (cond
-              ((match-kw "on")
+                ((match-kw "to")
-                (let
+                  (let
-                  ((target (parse-expr)))
+                    ((value (parse-expr)))
-                  (if
+                    (list (quote set!) tgt value)))
-                    (match-kw "to")
+                ((match-kw "on")
-                    (let
+                  (let
-                      ((value (parse-expr)))
+                    ((target (parse-expr)))
-                      (list (quote set-on!) tgt target value))
+                    (if
-                    (list (quote set-on) tgt target))))
+                      (match-kw "to")
-              (true (error (str "Expected to/on at position " p)))))))
+                      (let
+                        ((value (parse-expr)))
+                        (list (quote set-on!) tgt target value))
+                      (list (quote set-on) tgt target))))
+                (true (error (str "Expected to/on at position " p))))))))
       (define
         parse-put-cmd
         (fn

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

@@ -294,10 +294,13 @@
   hs-add-to!
   (fn
     (value target)
-    (if
+    (cond
-      (list? target)
+      ((list? target)
-      (append target (list value))
+        (if
-      (host-call target "push" value))))
+          (some (fn (x) (= x value)) target)
+          target
+          (append target (list value))))
+      (true (do (host-call target "push" value) target)))))
 
 ;; First/last within a specific scope.
 (define
@@ -664,7 +667,11 @@
       (cond
         ((nil? target) value)
         ((string? target) (str target value))
-        ((list? target) (append target (list value)))
+        ((list? target)
+          (if
+            (some (fn (x) (= x value)) target)
+            target
+            (append target (list value))))
         ((hs-element? target)
           (do
             (dom-insert-adjacent-html target "beforeend" (str value))
@@ -688,6 +695,61 @@
       ((fmt (cond ((nil? format) "text") ((or (= format "JSON") (= format "json") (= format "Object") (= format "object")) "json") ((or (= format "HTML") (= format "html")) "html") ((or (= format "Response") (= format "response")) "response") ((or (= format "Text") (= format "text")) "text") (true format))))
       (perform (list "io-fetch" url fmt)))))
 ;; Array slicing (inclusive both ends)
+(define
+  hs-json-escape
+  (fn
+    (s)
+    (str
+      "\""
+      (let
+        ((out "") (i 0) (n (string-length s)))
+        (define
+          walk
+          (fn
+            ()
+            (when
+              (< i n)
+              (let
+                ((c (substring s i (+ i 1))))
+                (set!
+                  out
+                  (cond
+                    ((= c "\\") (str out "\\\\"))
+                    ((= c "\"") (str out "\\\""))
+                    ((= c "\n") (str out "\\n"))
+                    ((= c "\r") (str out "\\r"))
+                    ((= c "\t") (str out "\\t"))
+                    (true (str out c))))
+                (set! i (+ i 1))
+                (walk)))))
+        (walk)
+        out)
+      "\"")))
+;; Collection: sorted by
+(define
+  hs-json-stringify
+  (fn
+    (v)
+    (cond
+      ((nil? v) "null")
+      ((= v true) "true")
+      ((= v false) "false")
+      ((number? v) (str v))
+      ((string? v) (hs-json-escape v))
+      ((list? v) (str "[" (join "," (map hs-json-stringify v)) "]"))
+      ((dict? v)
+        (str
+          "{"
+          (join
+            ","
+            (map
+              (fn
+                (k)
+                (str (hs-json-escape k) ":" (hs-json-stringify (get v k))))
+              (keys v)))
+          "}"))
+      (true (hs-json-escape (str v))))))
+;; Collection: sorted by descending
 (define
   hs-coerce
   (fn
@@ -705,19 +767,39 @@
       ((= type-name "Bool") (not (hs-falsy? value)))
       ((= type-name "Boolean") (not (hs-falsy? value)))
       ((= type-name "Array") (if (list? value) value (list value)))
-      ((= type-name "HTML") (str value))
+      ((= type-name "HTML")
+        (cond
+          ((list? value) (join "" (map (fn (x) (str x)) value)))
+          ((hs-element? value) (host-get value "outerHTML"))
+          (true (str value))))
       ((= type-name "JSON")
         (cond
           ((string? value) (guard (_e (true value)) (json-parse value)))
-          ((dict? value) (json-stringify value))
+          ((dict? value) (hs-json-stringify value))
-          ((list? value) (json-stringify value))
+          ((list? value) (hs-json-stringify value))
           (true value)))
       ((= type-name "Object")
         (if
           (string? value)
           (guard (_e (true value)) (json-parse value))
           value))
-      ((= type-name "JSONString") (json-stringify value))
+      ((= type-name "JSONString") (hs-json-stringify value))
+      ((= type-name "FormEncoded")
+        (if
+          (dict? value)
+          (join
+            "&"
+            (map
+              (fn
+                (k)
+                (let
+                  ((v (get value k)))
+                  (if
+                    (list? v)
+                    (join "&" (map (fn (item) (str k "=" item)) v))
+                    (str k "=" v))))
+              (keys value)))
+          (str value)))
       ((or (= type-name "Fixed") (= type-name "Fixed:") (starts-with? type-name "Fixed:"))
         (let
           ((digits (if (> (string-length type-name) 6) (+ (substring type-name 6 (string-length type-name)) 0) 0))
@@ -774,7 +856,7 @@
           (map (fn (k) (list k (get value k))) (keys value))
           value))
       (true value))))
-;; Collection: sorted by
+;; Collection: split by
 (define
   hs-gather-form-nodes
   (fn
@@ -808,11 +890,11 @@
                       (each 0)))))))))
       (walk root)
       acc)))
-;; Collection: sorted by descending
+;; Collection: joined by
 (define
   hs-values-from-nodes
   (fn (nodes) (reduce hs-values-absorb (dict) nodes)))
-;; Collection: split by
+
 (define
   hs-value-of-node
   (fn
@@ -828,7 +910,7 @@
         ((or (= typ "checkbox") (= typ "radio"))
           (if (host-get node "checked") (host-get node "value") nil))
         (true (host-get node "value"))))))
-;; Collection: joined by
+
 (define
   hs-select-multi-values
   (fn