Spec eval-cond and process-bindings in render.sx (remove platform implementations)

eval-cond and process-bindings were hand-written platform JS in
bootstrap_js.py rather than specced in .sx files. This violated the
SX host architecture principle. Now specced in render.sx as shared
render adapter helpers, bootstrapped to both JS and Python.

eval-cond handles both scheme-style ((test body) ...) and clojure-style
(test body test body ...) cond clauses. Returns unevaluated body
expression for the adapter to render in its own mode.

process-bindings evaluates let-binding pairs and returns extended env.

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

shared/static/scripts/sx-browser.js

@@ -493,39 +493,7 @@
     "map":1,"map-indexed":1,"filter":1,"reduce":1,"some":1,"every?":1,"for-each":1
   }; }
 
-  // processBindings and evalCond — exposed for DOM adapter render forms
-  function processBindings(bindings, env) {
-    var local = merge(env);
-    for (var i = 0; i < bindings.length; i++) {
-      var pair = bindings[i];
-      if (Array.isArray(pair) && pair.length >= 2) {
-        var name = isSym(pair[0]) ? pair[0].name : String(pair[0]);
-        local[name] = trampoline(evalExpr(pair[1], local));
-      }
-    }
-    return local;
-  }
-  function evalCond(clauses, env) {
-    // Detect scheme-style ((test body) ...) vs clojure-style (test body test body ...)
-    var scheme = clauses.length > 0 && Array.isArray(clauses[0]) && clauses[0].length === 2;
-    if (scheme) {
-      for (var i = 0; i < clauses.length; i++) {
-        var clause = clauses[i];
-        var test = clause[0], body = clause[1];
-        if (isSym(test) && (test.name === "else" || test.name === ":else")) return body;
-        if (isKw(test) && test.name === "else") return body;
-        if (isSxTruthy(trampoline(evalExpr(test, env)))) return body;
-      }
-    } else {
-      for (var i = 0; i < clauses.length; i += 2) {
-        var test = clauses[i];
-        if (isSym(test) && test.name === ":else") return clauses[i + 1];
-        if (isKw(test) && test.name === "else") return clauses[i + 1];
-        if (isSxTruthy(trampoline(evalExpr(test, env)))) return clauses[i + 1];
-      }
-    }
-    return null;
-  }
+  // processBindings and evalCond — now specced in render.sx, bootstrapped above
 
   function isDefinitionForm(name) {
     return name === "define" || name === "defcomp" || name === "defmacro" ||
@@ -1082,6 +1050,36 @@ return append_b(inits, nth(binding, 1)); }, bindings) : reduce(function(acc, pai
   return (isSxTruthy((isSxTruthy(contains(BOOLEAN_ATTRS, key)) && val)) ? (String(" ") + String(key)) : (isSxTruthy((isSxTruthy(contains(BOOLEAN_ATTRS, key)) && !val)) ? "" : (isSxTruthy(isNil(val)) ? "" : (isSxTruthy((isSxTruthy((key == "style")) && isStyleValue(val))) ? (String(" class=\"") + String(styleValueClass(val)) + String("\"")) : (String(" ") + String(key) + String("=\"") + String(escapeAttr((String(val)))) + String("\""))))));
 })(); }, keys(attrs))); };
 
+  // eval-cond
+  var evalCond = function(clauses, env) { return (isSxTruthy((isSxTruthy(!isEmpty(clauses)) && isSxTruthy((typeOf(first(clauses)) == "list")) && (len(first(clauses)) == 2))) ? evalCondScheme(clauses, env) : evalCondClojure(clauses, env)); };
+
+  // eval-cond-scheme
+  var evalCondScheme = function(clauses, env) { return (isSxTruthy(isEmpty(clauses)) ? NIL : (function() {
+  var clause = first(clauses);
+  var test = first(clause);
+  var body = nth(clause, 1);
+  return (isSxTruthy(sxOr((isSxTruthy((typeOf(test) == "symbol")) && sxOr((symbolName(test) == "else"), (symbolName(test) == ":else"))), (isSxTruthy((typeOf(test) == "keyword")) && (keywordName(test) == "else")))) ? body : (isSxTruthy(trampoline(evalExpr(test, env))) ? body : evalCondScheme(rest(clauses), env)));
+})()); };
+
+  // eval-cond-clojure
+  var evalCondClojure = function(clauses, env) { return (isSxTruthy((len(clauses) < 2)) ? NIL : (function() {
+  var test = first(clauses);
+  var body = nth(clauses, 1);
+  return (isSxTruthy(sxOr((isSxTruthy((typeOf(test) == "keyword")) && (keywordName(test) == "else")), (isSxTruthy((typeOf(test) == "symbol")) && sxOr((symbolName(test) == "else"), (symbolName(test) == ":else"))))) ? body : (isSxTruthy(trampoline(evalExpr(test, env))) ? body : evalCondClojure(slice(clauses, 2), env)));
+})()); };
+
+  // process-bindings
+  var processBindings = function(bindings, env) { return (function() {
+  var local = merge(env);
+  { var _c = bindings; for (var _i = 0; _i < _c.length; _i++) { var pair = _c[_i]; if (isSxTruthy((isSxTruthy((typeOf(pair) == "list")) && (len(pair) >= 2)))) {
+  (function() {
+  var name = (isSxTruthy((typeOf(first(pair)) == "symbol")) ? symbolName(first(pair)) : (String(first(pair))));
+  return envSet(local, name, trampoline(evalExpr(nth(pair, 1), local)));
+})();
+} } }
+  return local;
+})(); };
+
 
   // === Transpiled from parser ===
 

shared/sx/ref/bootstrap_js.py

@@ -273,6 +273,8 @@ class JSEmitter:
             "dict-delete!": "dictDelete",
             "process-bindings": "processBindings",
             "eval-cond": "evalCond",
+            "eval-cond-scheme": "evalCondScheme",
+            "eval-cond-clojure": "evalCondClojure",
             "for-each-indexed": "forEachIndexed",
             "index-of": "indexOf_",
             "component-has-children?": "componentHasChildren",
@@ -1823,39 +1825,7 @@ PLATFORM_JS_POST = '''
     "map":1,"map-indexed":1,"filter":1,"reduce":1,"some":1,"every?":1,"for-each":1
   }; }
 
-  // processBindings and evalCond — exposed for DOM adapter render forms
-  function processBindings(bindings, env) {
-    var local = merge(env);
-    for (var i = 0; i < bindings.length; i++) {
-      var pair = bindings[i];
-      if (Array.isArray(pair) && pair.length >= 2) {
-        var name = isSym(pair[0]) ? pair[0].name : String(pair[0]);
-        local[name] = trampoline(evalExpr(pair[1], local));
-      }
-    }
-    return local;
-  }
-  function evalCond(clauses, env) {
-    // Detect scheme-style ((test body) ...) vs clojure-style (test body test body ...)
-    var scheme = clauses.length > 0 && Array.isArray(clauses[0]) && clauses[0].length === 2;
-    if (scheme) {
-      for (var i = 0; i < clauses.length; i++) {
-        var clause = clauses[i];
-        var test = clause[0], body = clause[1];
-        if (isSym(test) && (test.name === "else" || test.name === ":else")) return body;
-        if (isKw(test) && test.name === "else") return body;
-        if (isSxTruthy(trampoline(evalExpr(test, env)))) return body;
-      }
-    } else {
-      for (var i = 0; i < clauses.length; i += 2) {
-        var test = clauses[i];
-        if (isSym(test) && test.name === ":else") return clauses[i + 1];
-        if (isKw(test) && test.name === "else") return clauses[i + 1];
-        if (isSxTruthy(trampoline(evalExpr(test, env)))) return clauses[i + 1];
-      }
-    }
-    return null;
-  }
+  // processBindings and evalCond — now specced in render.sx, bootstrapped above
 
   function isDefinitionForm(name) {
     return name === "define" || name === "defcomp" || name === "defmacro" ||

shared/sx/ref/bootstrap_py.py

@@ -236,6 +236,8 @@ class PyEmitter:
             "map-indexed": "map_indexed",
             "map-dict": "map_dict",
             "eval-cond": "eval_cond",
+            "eval-cond-scheme": "eval_cond_scheme",
+            "eval-cond-clojure": "eval_cond_clojure",
             "process-bindings": "process_bindings",
             # deps.sx
             "scan-refs": "scan_refs",

shared/sx/ref/render.sx

@@ -124,6 +124,75 @@
         (keys attrs)))))
 
 
+;; --------------------------------------------------------------------------
+;; Render adapter helpers
+;; --------------------------------------------------------------------------
+;; Shared by HTML and DOM adapters for evaluating control forms during
+;; rendering. Unlike sf-cond (eval.sx) which returns a thunk for TCO,
+;; eval-cond returns the unevaluated body expression so the adapter
+;; can render it in its own mode (HTML string vs DOM nodes).
+
+;; eval-cond: find matching cond branch, return unevaluated body expr.
+;; Handles both scheme-style ((test body) ...) and clojure-style
+;; (test body test body ...).
+(define eval-cond
+  (fn (clauses env)
+    (if (and (not (empty? clauses))
+             (= (type-of (first clauses)) "list")
+             (= (len (first clauses)) 2))
+      ;; Scheme-style
+      (eval-cond-scheme clauses env)
+      ;; Clojure-style
+      (eval-cond-clojure clauses env))))
+
+(define eval-cond-scheme
+  (fn (clauses env)
+    (if (empty? clauses)
+      nil
+      (let ((clause (first clauses))
+            (test   (first clause))
+            (body   (nth clause 1)))
+        (if (or (and (= (type-of test) "symbol")
+                     (or (= (symbol-name test) "else")
+                         (= (symbol-name test) ":else")))
+                (and (= (type-of test) "keyword")
+                     (= (keyword-name test) "else")))
+          body
+          (if (trampoline (eval-expr test env))
+            body
+            (eval-cond-scheme (rest clauses) env)))))))
+
+(define eval-cond-clojure
+  (fn (clauses env)
+    (if (< (len clauses) 2)
+      nil
+      (let ((test (first clauses))
+            (body (nth clauses 1)))
+        (if (or (and (= (type-of test) "keyword") (= (keyword-name test) "else"))
+                (and (= (type-of test) "symbol")
+                     (or (= (symbol-name test) "else")
+                         (= (symbol-name test) ":else"))))
+          body
+          (if (trampoline (eval-expr test env))
+            body
+            (eval-cond-clojure (slice clauses 2) env)))))))
+
+;; process-bindings: evaluate let-binding pairs, return extended env.
+;; bindings = ((name1 expr1) (name2 expr2) ...)
+(define process-bindings
+  (fn (bindings env)
+    (let ((local (merge env)))
+      (for-each
+        (fn (pair)
+          (when (and (= (type-of pair) "list") (>= (len pair) 2))
+            (let ((name (if (= (type-of (first pair)) "symbol")
+                          (symbol-name (first pair))
+                          (str (first pair)))))
+              (env-set! local name (trampoline (eval-expr (nth pair 1) local))))))
+        bindings)
+      local)))
+
+
 ;; --------------------------------------------------------------------------
 ;; Platform interface (shared across adapters)
 ;; --------------------------------------------------------------------------

shared/sx/ref/sx_ref.py

@@ -1140,6 +1140,18 @@ parse_element_args = lambda args, env: (lambda attrs: (lambda children: _sx_begi
 # render-attrs
 render_attrs = lambda attrs: join('', map(lambda key: (lambda val: (sx_str(' ', key) if sx_truthy((contains_p(BOOLEAN_ATTRS, key) if not sx_truthy(contains_p(BOOLEAN_ATTRS, key)) else val)) else ('' if sx_truthy((contains_p(BOOLEAN_ATTRS, key) if not sx_truthy(contains_p(BOOLEAN_ATTRS, key)) else (not sx_truthy(val)))) else ('' if sx_truthy(is_nil(val)) else (sx_str(' class="', style_value_class(val), '"') if sx_truthy(((key == 'style') if not sx_truthy((key == 'style')) else is_style_value(val))) else sx_str(' ', key, '="', escape_attr(sx_str(val)), '"'))))))(dict_get(attrs, key)), keys(attrs)))
 
+# eval-cond
+eval_cond = lambda clauses, env: (eval_cond_scheme(clauses, env) if sx_truthy(((not sx_truthy(empty_p(clauses))) if not sx_truthy((not sx_truthy(empty_p(clauses)))) else ((type_of(first(clauses)) == 'list') if not sx_truthy((type_of(first(clauses)) == 'list')) else (len(first(clauses)) == 2)))) else eval_cond_clojure(clauses, env))
+
+# eval-cond-scheme
+eval_cond_scheme = lambda clauses, env: (NIL if sx_truthy(empty_p(clauses)) else (lambda clause: (lambda test: (lambda body: (body if sx_truthy((((type_of(test) == 'symbol') if not sx_truthy((type_of(test) == 'symbol')) else ((symbol_name(test) == 'else') if sx_truthy((symbol_name(test) == 'else')) else (symbol_name(test) == ':else'))) if sx_truthy(((type_of(test) == 'symbol') if not sx_truthy((type_of(test) == 'symbol')) else ((symbol_name(test) == 'else') if sx_truthy((symbol_name(test) == 'else')) else (symbol_name(test) == ':else')))) else ((type_of(test) == 'keyword') if not sx_truthy((type_of(test) == 'keyword')) else (keyword_name(test) == 'else')))) else (body if sx_truthy(trampoline(eval_expr(test, env))) else eval_cond_scheme(rest(clauses), env))))(nth(clause, 1)))(first(clause)))(first(clauses)))
+
+# eval-cond-clojure
+eval_cond_clojure = lambda clauses, env: (NIL if sx_truthy((len(clauses) < 2)) else (lambda test: (lambda body: (body if sx_truthy((((type_of(test) == 'keyword') if not sx_truthy((type_of(test) == 'keyword')) else (keyword_name(test) == 'else')) if sx_truthy(((type_of(test) == 'keyword') if not sx_truthy((type_of(test) == 'keyword')) else (keyword_name(test) == 'else'))) else ((type_of(test) == 'symbol') if not sx_truthy((type_of(test) == 'symbol')) else ((symbol_name(test) == 'else') if sx_truthy((symbol_name(test) == 'else')) else (symbol_name(test) == ':else'))))) else (body if sx_truthy(trampoline(eval_expr(test, env))) else eval_cond_clojure(slice(clauses, 2), env))))(nth(clauses, 1)))(first(clauses)))
+
+# process-bindings
+process_bindings = lambda bindings, env: (lambda local: _sx_begin(for_each(lambda pair: ((lambda name: _sx_dict_set(local, name, trampoline(eval_expr(nth(pair, 1), local))))((symbol_name(first(pair)) if sx_truthy((type_of(first(pair)) == 'symbol')) else sx_str(first(pair)))) if sx_truthy(((type_of(pair) == 'list') if not sx_truthy((type_of(pair) == 'list')) else (len(pair) >= 2))) else NIL), bindings), local))(merge(env))
+
 
 # === Transpiled from adapter-html ===