HS: custom conversion API + asExpression tests (+2)

Add _hs-custom-conversions dict and _hs-dynamic-converters list to
runtime.sx. hs-set-conversion!/hs-clear-conversion!/hs-add-dynamic-converter!/
hs-pop-dynamic-converter!/hs-clear-converters! helpers expose the API.
hs-coerce fallback now checks static dict then dynamic resolvers before
returning value unchanged.

Hand-roll MANUAL_TEST_BODIES for "can accept custom conversions" and
"can accept custom dynamic conversions" — previously SKIP (untranslated).

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

lib/hyperscript/runtime.sx

@@ -1156,6 +1156,41 @@
             "}")))
       (true (hs-json-escape (str v))))))
 
+(begin
+  (define _hs-custom-conversions {})
+  (define _hs-dynamic-converters (list))
+  (define
+    hs-set-conversion!
+    (fn (name conv-fn) (dict-set! _hs-custom-conversions name conv-fn)))
+  (define
+    hs-clear-conversion!
+    (fn (name) (dict-set! _hs-custom-conversions name nil)))
+  (define
+    hs-add-dynamic-converter!
+    (fn
+      (conv-fn)
+      (set!
+        _hs-dynamic-converters
+        (append _hs-dynamic-converters (list conv-fn)))))
+  (define
+    hs-pop-dynamic-converter!
+    (fn
+      ()
+      (let
+        ((n (len _hs-dynamic-converters)))
+        (when
+          (> n 0)
+          (set!
+            _hs-dynamic-converters
+            (slice _hs-dynamic-converters 0 (- n 1)))))))
+  (define
+    hs-clear-converters!
+    (fn
+      ()
+      (do
+        (set! _hs-custom-conversions {})
+        (set! _hs-dynamic-converters (list))))))
+
 (define
   hs-coerce
   (fn
@@ -1280,7 +1315,15 @@
                 (filter (fn (k) (not (= k "_order"))) (keys value))))
             m)))
       ((= type-name "Date") (host-new "Date" value))
-      (true value))))
+      (true
+        (let
+          ((static-fn (get _hs-custom-conversions type-name)))
+          (if
+            (not (nil? static-fn))
+            (static-fn value)
+            (let
+              ((dynamic-result (reduce (fn (acc resolver) (if (not (nil? acc)) acc (resolver type-name value))) nil _hs-dynamic-converters)))
+              (if (not (nil? dynamic-result)) dynamic-result value))))))))
 
 (define
   hs-gather-form-nodes
@@ -2722,6 +2765,8 @@
       ((store (host-get el "__hs_vars")))
       (if (nil? store) nil (host-get store name)))))
 
+;; ── SourceInfo API ────────────────────────────────────────────────
+
 (define
   hs-dom-set-var-raw!
   (fn
@@ -2735,8 +2780,6 @@
         (host-set! (host-get el "__hs_vars") name val)
         (when changed (hs-dom-fire-watchers! el name val))))))
 
-;; ── SourceInfo API ────────────────────────────────────────────────
-
 (define
   hs-dom-resolve-start
   (fn

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

@@ -411,7 +411,7 @@
                   (do
                     (dom-set-inner-html target value)
                     (hs-boot-subtree! target)))))
-            ((= pos "beforebegin")
+            ((or (= pos "beforebegin") (= pos "before"))
               (if
                 (hs-element? value)
                 (let
@@ -422,7 +422,7 @@
                   (do
                     (dom-insert-adjacent-html target "beforebegin" value)
                     (when parent (hs-boot-subtree! parent))))))
-            ((= pos "afterend")
+            ((or (= pos "afterend") (= pos "after"))
               (if
                 (hs-element? value)
                 (let
@@ -439,7 +439,7 @@
                   (do
                     (dom-insert-adjacent-html target "afterend" value)
                     (when parent (hs-boot-subtree! parent))))))
-            ((= pos "afterbegin")
+            ((or (= pos "afterbegin") (= pos "start"))
               (cond
                 ((list? value) (append! target value 0))
                 ((hs-element? value) (dom-prepend target value))
@@ -447,7 +447,7 @@
                   (do
                     (dom-insert-adjacent-html target "afterbegin" value)
                     (hs-boot-subtree! target)))))
-            ((= pos "beforeend")
+            ((or (= pos "beforeend") (= pos "end"))
               (cond
                 ((list? value) (append! target value))
                 ((hs-element? value) (dom-append target value))
@@ -470,6 +470,7 @@
           (some (fn (x) (= x value)) target)
           target
           (append target (list value))))
+      ((hs-is-set? target) (do (host-call target "add" value) target))
       (true (do (host-call target "push" value) target)))))
 
 ;; ── Object creation ─────────────────────────────────────────────
@@ -480,10 +481,10 @@
   hs-remove-from!
   (fn
     (value target)
-    (if
+    (cond
-      (list? target)
+      ((list? target) (filter (fn (x) (not (= x value))) target))
-      (filter (fn (x) (not (= x value))) target)
+      ((hs-is-set? target) (do (host-call target "delete" value) target))
-      (host-call target "splice" (host-call target "indexOf" value) 1))))
+      (true (host-call target "splice" (host-call target "indexOf" value) 1)))))
 
 ;; ── Behavior installation ───────────────────────────────────────
 
@@ -965,6 +966,7 @@
             (some (fn (x) (= x value)) target)
             target
             (append target (list value))))
+        ((hs-is-set? target) (do (host-call target "add" value) target))
         ((hs-element? target)
           (do
             (dom-insert-adjacent-html
@@ -998,7 +1000,7 @@
     (event)
     (let
       ((detail (host-get event "detail")))
-      (if detail (host-get detail "sender") nil))))
+      (if detail (get detail "sender") nil))))
 
 (define
   hs-host-to-sx
@@ -1154,6 +1156,41 @@
             "}")))
       (true (hs-json-escape (str v))))))
 
+(begin
+  (define _hs-custom-conversions {})
+  (define _hs-dynamic-converters (list))
+  (define
+    hs-set-conversion!
+    (fn (name conv-fn) (dict-set! _hs-custom-conversions name conv-fn)))
+  (define
+    hs-clear-conversion!
+    (fn (name) (dict-set! _hs-custom-conversions name nil)))
+  (define
+    hs-add-dynamic-converter!
+    (fn
+      (conv-fn)
+      (set!
+        _hs-dynamic-converters
+        (append _hs-dynamic-converters (list conv-fn)))))
+  (define
+    hs-pop-dynamic-converter!
+    (fn
+      ()
+      (let
+        ((n (len _hs-dynamic-converters)))
+        (when
+          (> n 0)
+          (set!
+            _hs-dynamic-converters
+            (slice _hs-dynamic-converters 0 (- n 1)))))))
+  (define
+    hs-clear-converters!
+    (fn
+      ()
+      (do
+        (set! _hs-custom-conversions {})
+        (set! _hs-dynamic-converters (list))))))
+
 (define
   hs-coerce
   (fn
@@ -1260,23 +1297,33 @@
             value)
           value))
       ((= type-name "Set")
-        (if
+        (let
-          (list? value)
+          ((s (host-new "Set")))
-          (reduce
+          (do
-            (fn
+            (when
-              (acc x)
+              (list? value)
-              (if (some (fn (a) (= a x)) acc) acc (append acc (list x))))
+              (for-each (fn (x) (host-call s "add" x)) value))
-            (list)
+            s)))
-            value)
-          value))
       ((= type-name "Map")
-        (if
+        (let
-          (dict? value)
+          ((m (host-new "Map")))
-          (let
+          (do
-            ((ks (if (dict-has? value "_order") (get value "_order") (filter (fn (k) (not (= k "_order"))) (keys value)))))
+            (when
-            (map (fn (k) (list k (get value k))) ks))
+              (dict? value)
-          value))
+              (for-each
-      (true value))))
+                (fn (k) (host-call m "set" k (get value k)))
+                (filter (fn (k) (not (= k "_order"))) (keys value))))
+            m)))
+      ((= type-name "Date") (host-new "Date" value))
+      (true
+        (let
+          ((static-fn (get _hs-custom-conversions type-name)))
+          (if
+            (not (nil? static-fn))
+            (static-fn value)
+            (let
+              ((dynamic-result (reduce (fn (acc resolver) (if (not (nil? acc)) acc (resolver type-name value))) nil _hs-dynamic-converters)))
+              (if (not (nil? dynamic-result)) dynamic-result value))))))))
 
 (define
   hs-gather-form-nodes
@@ -1471,8 +1518,8 @@
             (cond
               ((= type-name "Object") (dict))
               ((= type-name "Array") (list))
-              ((= type-name "Set") (list))
+              ((= type-name "Set") (host-new "Set"))
-              ((= type-name "Map") (dict))
+              ((= type-name "Map") (host-new "Map"))
               (true (dict)))
             (apply host-new (cons type-name args)))))))
   (define
@@ -1871,6 +1918,8 @@
     (cond
       ((list? v) (list))
       ((dict? v) (dict))
+      ((hs-is-set? v) (host-new "Set"))
+      ((hs-is-map? v) (host-new "Map"))
       ((string? v) "")
       ((nil? v) nil)
       (true v))))
@@ -2386,6 +2435,26 @@
           pairs)
         d))))
 
+(define
+  hs-strip-order-deep
+  (fn
+    (val)
+    (cond
+      ((dict? val)
+        (let
+          ((d (dict)))
+          (do
+            (for-each
+              (fn
+                (k)
+                (when
+                  (not (= k "_order"))
+                  (dict-set! d k (hs-strip-order-deep (get val k)))))
+              (filter (fn (k) (not (= k "_order"))) (keys val)))
+            d)))
+      ((list? val) (map hs-strip-order-deep val))
+      (true val))))
+
 (define
   hs-method-call
   (fn
@@ -2696,6 +2765,8 @@
       ((store (host-get el "__hs_vars")))
       (if (nil? store) nil (host-get store name)))))
 
+;; ── SourceInfo API ────────────────────────────────────────────────
+
 (define
   hs-dom-set-var-raw!
   (fn
@@ -2728,8 +2799,6 @@
               (if match (dom-parent match) nil)))
           (true el))))))
 
-;; ── SourceInfo API ────────────────────────────────────────────────
-
 (define
   hs-dom-walk
   (fn

spec/tests/test-hyperscript-behavioral.sx

@@ -3724,9 +3724,25 @@
 ;; ── expressions/asExpression (42 tests) ──
 (defsuite "hs-upstream-expressions/asExpression"
   (deftest "can accept custom conversions"
-    (error "SKIP (untranslated): can accept custom conversions"))
+    (do
+      (hs-set-conversion! "Foo" (fn (val) (str "foo" (str val))))
+      (let ((result (hs-coerce 1 "Foo")))
+        (do
+          (hs-clear-conversion! "Foo")
+          (assert= result "foo1"))))
+  )
   (deftest "can accept custom dynamic conversions"
-    (error "SKIP (untranslated): can accept custom dynamic conversions"))
+    (do
+      (hs-add-dynamic-converter!
+        (fn (conversion val)
+          (if (= (host-call conversion "indexOf" "Foo:") 0)
+            (str (host-call conversion "slice" 4) (str val))
+            nil)))
+      (let ((result (hs-coerce 1 "Foo:Bar")))
+        (do
+          (hs-pop-dynamic-converter!)
+          (assert= result "Bar1"))))
+  )
   (deftest "can use the a modifier if you like"
     (let ((_result (eval-hs "1 as a Date")))
       (assert= (host-call _result "getTime") 1))

tests/playwright/generate-sx-tests.py

@@ -326,6 +326,27 @@ MANUAL_TEST_BODIES = {
         '          (list (list (quote record) record)))',
         '        "<div age=\\"21\\" style=\\"color:bleaux\\">John Connor</div>"))',
     ],
+    # asExpression: custom conversions — set/clear via hs-set-conversion! + hs-add-dynamic-converter!
+    "can accept custom conversions": [
+        '    (do',
+        '      (hs-set-conversion! "Foo" (fn (val) (str "foo" (str val))))',
+        '      (let ((result (hs-coerce 1 "Foo")))',
+        '        (do',
+        '          (hs-clear-conversion! "Foo")',
+        '          (assert= result "foo1"))))',
+    ],
+    "can accept custom dynamic conversions": [
+        '    (do',
+        '      (hs-add-dynamic-converter!',
+        '        (fn (conversion val)',
+        '          (if (= (host-call conversion "indexOf" "Foo:") 0)',
+        '            (str (host-call conversion "slice" 4) (str val))',
+        '            nil)))',
+        '      (let ((result (hs-coerce 1 "Foo:Bar")))',
+        '        (do',
+        '          (hs-pop-dynamic-converter!)',
+        '          (assert= result "Bar1"))))',
+    ],
     # asExpression: Date/Set/Map need real JS host objects
     "converts value as Date": [
         '    (let ((_result (eval-hs "1 as Date")))',