Add TCO for parser loops in JS bootstrapper, enable SX_USE_REF

The JS parser transpiled from parser.sx used tail-recursive functions
(readStrLoop, skipWs, readListLoop, etc.) which overflow the stack on
large inputs — the bootstrapper page highlights 100KB of Python and
143KB of JavaScript, producing 7620 spans in a 907KB response.

The bootstrapper now detects zero-arg self-tail-recursive functions and
emits them as while(true) loops with continue instead of recursive
calls. Tested with 150K char strings and 8000 sibling elements.

Also enables SX_USE_REF=1 in dev via x-dev-env anchor.

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

docker-compose.dev.yml

@@ -10,6 +10,7 @@
 x-dev-env: &dev-env
   RELOAD: "true"
   WORKERS: "1"
+  SX_USE_REF: "1"
 
 x-sibling-models: &sibling-models
   # Every app needs all sibling __init__.py + models/ for cross-domain SQLAlchemy imports

shared/static/scripts/sx-browser.js

@@ -508,6 +508,25 @@
     return NIL;
   }
 
+  // =========================================================================
+  // Platform interface — Parser
+  // =========================================================================
+  // Character classification derived from the grammar:
+  //   ident-start → [a-zA-Z_~*+\-><=/!?&]
+  //   ident-char  → ident-start + [0-9.:\/\[\]#,]
+
+  var _identStartRe = /[a-zA-Z_~*+\-><=/!?&]/;
+  var _identCharRe = /[a-zA-Z0-9_~*+\-><=/!?.:&/\[\]#,]/;
+
+  function isIdentStart(ch) { return _identStartRe.test(ch); }
+  function isIdentChar(ch) { return _identCharRe.test(ch); }
+  function parseNumber(s) { return Number(s); }
+  function escapeString(s) {
+    return s.replace(/\\/g, "\\\\").replace(/"/g, '\\"').replace(/\n/g, "\\n").replace(/\t/g, "\\t");
+  }
+  function sxExprSource(e) { return typeof e === "string" ? e : String(e); }
+
+
   // === Transpiled from eval ===
 
   // trampoline
@@ -528,10 +547,10 @@
   var args = rest(expr);
   return (isSxTruthy(!sxOr((typeOf(head) == "symbol"), (typeOf(head) == "lambda"), (typeOf(head) == "list"))) ? map(function(x) { return trampoline(evalExpr(x, env)); }, expr) : (isSxTruthy((typeOf(head) == "symbol")) ? (function() {
   var name = symbolName(head);
-  return (isSxTruthy((name == "if")) ? sfIf(args, env) : (isSxTruthy((name == "when")) ? sfWhen(args, env) : (isSxTruthy((name == "cond")) ? sfCond(args, env) : (isSxTruthy((name == "case")) ? sfCase(args, env) : (isSxTruthy((name == "and")) ? sfAnd(args, env) : (isSxTruthy((name == "or")) ? sfOr(args, env) : (isSxTruthy((name == "let")) ? sfLet(args, env) : (isSxTruthy((name == "let*")) ? sfLet(args, env) : (isSxTruthy((name == "lambda")) ? sfLambda(args, env) : (isSxTruthy((name == "fn")) ? sfLambda(args, env) : (isSxTruthy((name == "define")) ? sfDefine(args, env) : (isSxTruthy((name == "defcomp")) ? sfDefcomp(args, env) : (isSxTruthy((name == "defmacro")) ? sfDefmacro(args, env) : (isSxTruthy((name == "defstyle")) ? sfDefstyle(args, env) : (isSxTruthy((name == "defkeyframes")) ? sfDefkeyframes(args, env) : (isSxTruthy((name == "defhandler")) ? sfDefine(args, env) : (isSxTruthy((name == "begin")) ? sfBegin(args, env) : (isSxTruthy((name == "do")) ? sfBegin(args, env) : (isSxTruthy((name == "quote")) ? sfQuote(args, env) : (isSxTruthy((name == "quasiquote")) ? sfQuasiquote(args, env) : (isSxTruthy((name == "->")) ? sfThreadFirst(args, env) : (isSxTruthy((name == "set!")) ? sfSetBang(args, env) : (isSxTruthy((name == "map")) ? hoMap(args, env) : (isSxTruthy((name == "map-indexed")) ? hoMapIndexed(args, env) : (isSxTruthy((name == "filter")) ? hoFilter(args, env) : (isSxTruthy((name == "reduce")) ? hoReduce(args, env) : (isSxTruthy((name == "some")) ? hoSome(args, env) : (isSxTruthy((name == "every?")) ? hoEvery(args, env) : (isSxTruthy((name == "for-each")) ? hoForEach(args, env) : (isSxTruthy((isSxTruthy(envHas(env, name)) && isMacro(envGet(env, name)))) ? (function() {
+  return (isSxTruthy((name == "if")) ? sfIf(args, env) : (isSxTruthy((name == "when")) ? sfWhen(args, env) : (isSxTruthy((name == "cond")) ? sfCond(args, env) : (isSxTruthy((name == "case")) ? sfCase(args, env) : (isSxTruthy((name == "and")) ? sfAnd(args, env) : (isSxTruthy((name == "or")) ? sfOr(args, env) : (isSxTruthy((name == "let")) ? sfLet(args, env) : (isSxTruthy((name == "let*")) ? sfLet(args, env) : (isSxTruthy((name == "lambda")) ? sfLambda(args, env) : (isSxTruthy((name == "fn")) ? sfLambda(args, env) : (isSxTruthy((name == "define")) ? sfDefine(args, env) : (isSxTruthy((name == "defcomp")) ? sfDefcomp(args, env) : (isSxTruthy((name == "defmacro")) ? sfDefmacro(args, env) : (isSxTruthy((name == "defstyle")) ? sfDefstyle(args, env) : (isSxTruthy((name == "defkeyframes")) ? sfDefkeyframes(args, env) : (isSxTruthy((name == "defhandler")) ? sfDefhandler(args, env) : (isSxTruthy((name == "defpage")) ? sfDefpage(args, env) : (isSxTruthy((name == "defquery")) ? sfDefquery(args, env) : (isSxTruthy((name == "defaction")) ? sfDefaction(args, env) : (isSxTruthy((name == "begin")) ? sfBegin(args, env) : (isSxTruthy((name == "do")) ? sfBegin(args, env) : (isSxTruthy((name == "quote")) ? sfQuote(args, env) : (isSxTruthy((name == "quasiquote")) ? sfQuasiquote(args, env) : (isSxTruthy((name == "->")) ? sfThreadFirst(args, env) : (isSxTruthy((name == "set!")) ? sfSetBang(args, env) : (isSxTruthy((name == "map")) ? hoMap(args, env) : (isSxTruthy((name == "map-indexed")) ? hoMapIndexed(args, env) : (isSxTruthy((name == "filter")) ? hoFilter(args, env) : (isSxTruthy((name == "reduce")) ? hoReduce(args, env) : (isSxTruthy((name == "some")) ? hoSome(args, env) : (isSxTruthy((name == "every?")) ? hoEvery(args, env) : (isSxTruthy((name == "for-each")) ? hoForEach(args, env) : (isSxTruthy((isSxTruthy(envHas(env, name)) && isMacro(envGet(env, name)))) ? (function() {
   var mac = envGet(env, name);
   return makeThunk(expandMacro(mac, args, env), env);
-})() : (isSxTruthy(isRenderExpr(expr)) ? renderExpr(expr, env) : evalCall(head, args, env))))))))))))))))))))))))))))))));
+})() : (isSxTruthy(isRenderExpr(expr)) ? renderExpr(expr, env) : evalCall(head, args, env)))))))))))))))))))))))))))))))))));
 })() : evalCall(head, args, env)));
 })(); };
 
@@ -788,25 +807,28 @@
   return trampoline(evalExpr(macroBody(mac), local));
 })(); };
 
+  // call-fn
+  var callFn = function(f, args, env) { return (isSxTruthy(isLambda(f)) ? trampoline(callLambda(f, args, env)) : (isSxTruthy(isCallable(f)) ? apply(f, args) : error((String("Not callable in HO form: ") + String(inspect(f)))))); };
+
   // ho-map
   var hoMap = function(args, env) { return (function() {
   var f = trampoline(evalExpr(first(args), env));
   var coll = trampoline(evalExpr(nth(args, 1), env));
-  return map(function(item) { return trampoline(callLambda(f, [item], env)); }, coll);
+  return map(function(item) { return callFn(f, [item], env); }, coll);
 })(); };
 
   // ho-map-indexed
   var hoMapIndexed = function(args, env) { return (function() {
   var f = trampoline(evalExpr(first(args), env));
   var coll = trampoline(evalExpr(nth(args, 1), env));
-  return mapIndexed(function(i, item) { return trampoline(callLambda(f, [i, item], env)); }, coll);
+  return mapIndexed(function(i, item) { return callFn(f, [i, item], env); }, coll);
 })(); };
 
   // ho-filter
   var hoFilter = function(args, env) { return (function() {
   var f = trampoline(evalExpr(first(args), env));
   var coll = trampoline(evalExpr(nth(args, 1), env));
-  return filter(function(item) { return trampoline(callLambda(f, [item], env)); }, coll);
+  return filter(function(item) { return callFn(f, [item], env); }, coll);
 })(); };
 
   // ho-reduce
@@ -814,28 +836,28 @@
   var f = trampoline(evalExpr(first(args), env));
   var init = trampoline(evalExpr(nth(args, 1), env));
   var coll = trampoline(evalExpr(nth(args, 2), env));
-  return reduce(function(acc, item) { return trampoline(callLambda(f, [acc, item], env)); }, init, coll);
+  return reduce(function(acc, item) { return callFn(f, [acc, item], env); }, init, coll);
 })(); };
 
   // ho-some
   var hoSome = function(args, env) { return (function() {
   var f = trampoline(evalExpr(first(args), env));
   var coll = trampoline(evalExpr(nth(args, 1), env));
-  return some(function(item) { return trampoline(callLambda(f, [item], env)); }, coll);
+  return some(function(item) { return callFn(f, [item], env); }, coll);
 })(); };
 
   // ho-every
   var hoEvery = function(args, env) { return (function() {
   var f = trampoline(evalExpr(first(args), env));
   var coll = trampoline(evalExpr(nth(args, 1), env));
-  return isEvery(function(item) { return trampoline(callLambda(f, [item], env)); }, coll);
+  return isEvery(function(item) { return callFn(f, [item], env); }, coll);
 })(); };
 
   // ho-for-each
   var hoForEach = function(args, env) { return (function() {
   var f = trampoline(evalExpr(first(args), env));
   var coll = trampoline(evalExpr(nth(args, 1), env));
-  return forEach(function(item) { return trampoline(callLambda(f, [item], env)); }, coll);
+  return forEach(function(item) { return callFn(f, [item], env); }, coll);
 })(); };
 
 
@@ -875,6 +897,117 @@
 })(); }, keys(attrs))); };
 
 
+  // === Transpiled from parser ===
+
+  // sx-parse
+  var sxParse = function(source) { return (function() {
+  var pos = 0;
+  var lenSrc = len(source);
+  var skipComment = function() { while(true) { if (isSxTruthy((isSxTruthy((pos < lenSrc)) && !(nth(source, pos) == "\n")))) { pos = (pos + 1);
+continue; } else { return NIL; } } };
+  var skipWs = function() { while(true) { if (isSxTruthy((pos < lenSrc))) { { var ch = nth(source, pos);
+if (isSxTruthy(sxOr((ch == " "), (ch == "\t"), (ch == "\n"), (ch == "\\r")))) { pos = (pos + 1);
+continue; } else if (isSxTruthy((ch == ";"))) { pos = (pos + 1);
+skipComment();
+continue; } else { return NIL; } } } else { return NIL; } } };
+  var readString = function() { pos = (pos + 1);
+return (function() {
+  var buf = "";
+  var readStrLoop = function() { while(true) { if (isSxTruthy((pos >= lenSrc))) { return error("Unterminated string"); } else { { var ch = nth(source, pos);
+if (isSxTruthy((ch == "\""))) { pos = (pos + 1);
+return NIL; } else if (isSxTruthy((ch == "\\"))) { pos = (pos + 1);
+{ var esc = nth(source, pos);
+buf = (String(buf) + String((isSxTruthy((esc == "n")) ? "\n" : (isSxTruthy((esc == "t")) ? "\t" : (isSxTruthy((esc == "r")) ? "\\r" : esc)))));
+pos = (pos + 1);
+continue; } } else { buf = (String(buf) + String(ch));
+pos = (pos + 1);
+continue; } } } } };
+  readStrLoop();
+  return buf;
+})(); };
+  var readIdent = function() { return (function() {
+  var start = pos;
+  var readIdentLoop = function() { while(true) { if (isSxTruthy((isSxTruthy((pos < lenSrc)) && isIdentChar(nth(source, pos))))) { pos = (pos + 1);
+continue; } else { return NIL; } } };
+  readIdentLoop();
+  return slice(source, start, pos);
+})(); };
+  var readKeyword = function() { pos = (pos + 1);
+return makeKeyword(readIdent()); };
+  var readNumber = function() { return (function() {
+  var start = pos;
+  if (isSxTruthy((isSxTruthy((pos < lenSrc)) && (nth(source, pos) == "-")))) {
+  pos = (pos + 1);
+}
+  var readDigits = function() { while(true) { if (isSxTruthy((isSxTruthy((pos < lenSrc)) && (function() {
+  var c = nth(source, pos);
+  return (isSxTruthy((c >= "0")) && (c <= "9"));
+})()))) { pos = (pos + 1);
+continue; } else { return NIL; } } };
+  readDigits();
+  if (isSxTruthy((isSxTruthy((pos < lenSrc)) && (nth(source, pos) == ".")))) {
+  pos = (pos + 1);
+  readDigits();
+}
+  if (isSxTruthy((isSxTruthy((pos < lenSrc)) && sxOr((nth(source, pos) == "e"), (nth(source, pos) == "E"))))) {
+  pos = (pos + 1);
+  if (isSxTruthy((isSxTruthy((pos < lenSrc)) && sxOr((nth(source, pos) == "+"), (nth(source, pos) == "-"))))) {
+  pos = (pos + 1);
+}
+  readDigits();
+}
+  return parseNumber(slice(source, start, pos));
+})(); };
+  var readSymbol = function() { return (function() {
+  var name = readIdent();
+  return (isSxTruthy((name == "true")) ? true : (isSxTruthy((name == "false")) ? false : (isSxTruthy((name == "nil")) ? NIL : makeSymbol(name))));
+})(); };
+  var readList = function(closeCh) { return (function() {
+  var items = [];
+  var readListLoop = function() { while(true) { skipWs();
+if (isSxTruthy((pos >= lenSrc))) { return error("Unterminated list"); } else { if (isSxTruthy((nth(source, pos) == closeCh))) { pos = (pos + 1);
+return NIL; } else { items.push(readExpr());
+continue; } } } };
+  readListLoop();
+  return items;
+})(); };
+  var readMap = function() { return (function() {
+  var result = {};
+  var readMapLoop = function() { while(true) { skipWs();
+if (isSxTruthy((pos >= lenSrc))) { return error("Unterminated map"); } else { if (isSxTruthy((nth(source, pos) == "}"))) { pos = (pos + 1);
+return NIL; } else { { var keyExpr = readExpr();
+var keyStr = (isSxTruthy((typeOf(keyExpr) == "keyword")) ? keywordName(keyExpr) : (String(keyExpr)));
+var valExpr = readExpr();
+result[keyStr] = valExpr;
+continue; } } } } };
+  readMapLoop();
+  return result;
+})(); };
+  var readExpr = function() { skipWs();
+return (isSxTruthy((pos >= lenSrc)) ? error("Unexpected end of input") : (function() {
+  var ch = nth(source, pos);
+  return (isSxTruthy((ch == "(")) ? ((pos = (pos + 1)), readList(")")) : (isSxTruthy((ch == "[")) ? ((pos = (pos + 1)), readList("]")) : (isSxTruthy((ch == "{")) ? ((pos = (pos + 1)), readMap()) : (isSxTruthy((ch == "\"")) ? readString() : (isSxTruthy((ch == ":")) ? readKeyword() : (isSxTruthy((ch == "`")) ? ((pos = (pos + 1)), [makeSymbol("quasiquote"), readExpr()]) : (isSxTruthy((ch == ",")) ? ((pos = (pos + 1)), (isSxTruthy((isSxTruthy((pos < lenSrc)) && (nth(source, pos) == "@"))) ? ((pos = (pos + 1)), [makeSymbol("splice-unquote"), readExpr()]) : [makeSymbol("unquote"), readExpr()])) : (isSxTruthy(sxOr((isSxTruthy((ch >= "0")) && (ch <= "9")), (isSxTruthy((ch == "-")) && isSxTruthy(((pos + 1) < lenSrc)) && (function() {
+  var nextCh = nth(source, (pos + 1));
+  return (isSxTruthy((nextCh >= "0")) && (nextCh <= "9"));
+})()))) ? readNumber() : (isSxTruthy(isIdentStart(ch)) ? readSymbol() : error((String("Unexpected character: ") + String(ch))))))))))));
+})()); };
+  return (function() {
+  var exprs = [];
+  var parseLoop = function() { while(true) { skipWs();
+if (isSxTruthy((pos < lenSrc))) { exprs.push(readExpr());
+continue; } else { return NIL; } } };
+  parseLoop();
+  return exprs;
+})();
+})(); };
+
+  // sx-serialize
+  var sxSerialize = function(val) { return (function() { var _m = typeOf(val); if (_m == "nil") return "nil"; if (_m == "boolean") return (isSxTruthy(val) ? "true" : "false"); if (_m == "number") return (String(val)); if (_m == "string") return (String("\"") + String(escapeString(val)) + String("\"")); if (_m == "symbol") return symbolName(val); if (_m == "keyword") return (String(":") + String(keywordName(val))); if (_m == "list") return (String("(") + String(join(" ", map(sxSerialize, val))) + String(")")); if (_m == "dict") return sxSerializeDict(val); if (_m == "sx-expr") return sxExprSource(val); return (String(val)); })(); };
+
+  // sx-serialize-dict
+  var sxSerializeDict = function(d) { return (String("{") + String(join(" ", reduce(function(acc, key) { return concat(acc, [(String(":") + String(key)), sxSerialize(dictGet(d, key))]); }, [], keys(d)))) + String("}")); };
+
+
   // === Transpiled from adapter-dom ===
 
   // SVG_NS
@@ -1284,7 +1417,7 @@ return forEach(function(attr) { return (isSxTruthy(!domHasAttr(newEl, first(attr
   var _preloadCache = {};
 
   // _css-hash
-  var _cssHash = "";
+  var _cssHash = NIL;
 
   // dispatch-trigger-events
   var dispatchTriggerEvents = function(el, headerVal) { return (isSxTruthy(headerVal) ? (function() {
@@ -1747,7 +1880,7 @@ return (_styleCache = {}); };
   return (isSxTruthy(decls) ? ((isSxTruthy(startsWith(base, "animate-")) ? (function() {
   var kfName = slice(base, 8);
   return (isSxTruthy(dictHas(_styleKeyframes, kfName)) ? append_b(kfNeeded, [kfName, dictGet(_styleKeyframes, kfName)]) : NIL);
-})() : NIL), (isSxTruthy(isNil(variant)) ? append_b(baseDecls, decls) : (isSxTruthy(dictHas(_responsiveBreakpoints, variant)) ? append_b(mediaRules, [dictGet(_responsiveBreakpoints, variant), decls]) : (isSxTruthy(dictHas(_pseudoVariants, variant)) ? append_b(pseudoRules, [dictGet(_pseudoVariants, variant), decls]) : (function() {
+})() : NIL), (isSxTruthy(isNil(variant)) ? (isSxTruthy(isChildSelectorAtom(base)) ? append_b(pseudoRules, [">:not(:first-child)", decls]) : append_b(baseDecls, decls)) : (isSxTruthy(dictHas(_responsiveBreakpoints, variant)) ? append_b(mediaRules, [dictGet(_responsiveBreakpoints, variant), decls]) : (isSxTruthy(dictHas(_pseudoVariants, variant)) ? append_b(pseudoRules, [dictGet(_pseudoVariants, variant), decls]) : (function() {
   var vparts = split(variant, ":");
   var mediaPart = NIL;
   var pseudoPart = NIL;
@@ -1766,12 +1899,12 @@ return (_styleCache = {}); };
 } } }
   return (function() {
   var hashInput = join(";", baseDecls);
-  { var _c = chunkEvery(mediaRules, 2); for (var _i = 0; _i < _c.length; _i++) { var mr = _c[_i]; hashInput = (String(hashInput) + String("@") + String(first(mr)) + String("{") + String(nth(mr, 1)) + String("}")); } }
-  { var _c = chunkEvery(pseudoRules, 2); for (var _i = 0; _i < _c.length; _i++) { var pr = _c[_i]; hashInput = (String(hashInput) + String(first(pr)) + String("{") + String(nth(pr, 1)) + String("}")); } }
-  { var _c = chunkEvery(kfNeeded, 2); for (var _i = 0; _i < _c.length; _i++) { var kf = _c[_i]; hashInput = (String(hashInput) + String(nth(kf, 1))); } }
+  { var _c = mediaRules; for (var _i = 0; _i < _c.length; _i++) { var mr = _c[_i]; hashInput = (String(hashInput) + String("@") + String(first(mr)) + String("{") + String(nth(mr, 1)) + String("}")); } }
+  { var _c = pseudoRules; for (var _i = 0; _i < _c.length; _i++) { var pr = _c[_i]; hashInput = (String(hashInput) + String(first(pr)) + String("{") + String(nth(pr, 1)) + String("}")); } }
+  { var _c = kfNeeded; for (var _i = 0; _i < _c.length; _i++) { var kf = _c[_i]; hashInput = (String(hashInput) + String(nth(kf, 1))); } }
   return (function() {
   var cn = (String("sx-") + String(hashStyle(hashInput)));
-  var sv = makeStyleValue_(cn, join(";", baseDecls), chunkEvery(mediaRules, 2), chunkEvery(pseudoRules, 2), chunkEvery(kfNeeded, 2));
+  var sv = makeStyleValue_(cn, join(";", baseDecls), mediaRules, pseudoRules, kfNeeded);
   _styleCache[key] = sv;
   injectStyleValue(sv, atoms);
   return sv;
@@ -2740,18 +2873,11 @@ callExpr.push(dictGet(kwargs, k)); } }
     if (!cssTarget) return;
 
     var rules = [];
+    // Child-selector atoms are now routed to pseudoRules by the resolver
+    // with selector ">:not(:first-child)", so base declarations are always
+    // applied directly to the class.
     if (sv.declarations) {
-      var hasChild = false;
-      if (atoms) {
-        for (var ai = 0; ai < atoms.length; ai++) {
-          if (isChildSelectorAtom(atoms[ai])) { hasChild = true; break; }
-        }
-      }
-      if (hasChild) {
-        rules.push("." + sv.className + ">:not(:first-child){" + sv.declarations + "}");
-      } else {
-        rules.push("." + sv.className + "{" + sv.declarations + "}");
-      }
+      rules.push("." + sv.className + "{" + sv.declarations + "}");
     }
     for (var pi = 0; pi < sv.pseudoRules.length; pi++) {
       var sel = sv.pseudoRules[pi][0], decls = sv.pseudoRules[pi][1];
@@ -2952,107 +3078,8 @@ callExpr.push(dictGet(kwargs, k)); } }
   // Expose render functions as primitives so SX code can call them
   if (typeof renderToDom === "function") PRIMITIVES["render-to-dom"] = renderToDom;
 
-  // =========================================================================
-  // Parser
-  // =========================================================================
-
-  function parse(text) {
-    var pos = 0;
-    function skipWs() {
-      while (pos < text.length) {
-        var ch = text[pos];
-        if (ch === " " || ch === "\t" || ch === "\n" || ch === "\r") { pos++; continue; }
-        if (ch === ";") { while (pos < text.length && text[pos] !== "\n") pos++; continue; }
-        break;
-      }
-    }
-    function readExpr() {
-      skipWs();
-      if (pos >= text.length) return undefined;
-      var ch = text[pos];
-      if (ch === "(") { pos++; return readList(")"); }
-      if (ch === "[") { pos++; return readList("]"); }
-      if (ch === "{") { pos++; return readMap(); }
-      if (ch === '"') return readString();
-      if (ch === ":") return readKeyword();
-      if (ch === "`") { pos++; return [new Symbol("quasiquote"), readExpr()]; }
-      if (ch === ",") {
-        pos++;
-        if (pos < text.length && text[pos] === "@") { pos++; return [new Symbol("splice-unquote"), readExpr()]; }
-        return [new Symbol("unquote"), readExpr()];
-      }
-      if (ch === "-" && pos + 1 < text.length && text[pos + 1] >= "0" && text[pos + 1] <= "9") return readNumber();
-      if (ch >= "0" && ch <= "9") return readNumber();
-      return readSymbol();
-    }
-    function readList(close) {
-      var items = [];
-      while (true) {
-        skipWs();
-        if (pos >= text.length) throw new Error("Unterminated list");
-        if (text[pos] === close) { pos++; return items; }
-        items.push(readExpr());
-      }
-    }
-    function readMap() {
-      var result = {};
-      while (true) {
-        skipWs();
-        if (pos >= text.length) throw new Error("Unterminated map");
-        if (text[pos] === "}") { pos++; return result; }
-        var key = readExpr();
-        var keyStr = (key && key._kw) ? key.name : String(key);
-        result[keyStr] = readExpr();
-      }
-    }
-    function readString() {
-      pos++; // skip "
-      var s = "";
-      while (pos < text.length) {
-        var ch = text[pos];
-        if (ch === '"') { pos++; return s; }
-        if (ch === "\\") { pos++; var esc = text[pos]; s += esc === "n" ? "\n" : esc === "t" ? "\t" : esc === "r" ? "\r" : esc; pos++; continue; }
-        s += ch; pos++;
-      }
-      throw new Error("Unterminated string");
-    }
-    function readKeyword() {
-      pos++; // skip :
-      var name = readIdent();
-      return new Keyword(name);
-    }
-    function readNumber() {
-      var start = pos;
-      if (text[pos] === "-") pos++;
-      while (pos < text.length && text[pos] >= "0" && text[pos] <= "9") pos++;
-      if (pos < text.length && text[pos] === ".") { pos++; while (pos < text.length && text[pos] >= "0" && text[pos] <= "9") pos++; }
-      if (pos < text.length && (text[pos] === "e" || text[pos] === "E")) {
-        pos++;
-        if (pos < text.length && (text[pos] === "+" || text[pos] === "-")) pos++;
-        while (pos < text.length && text[pos] >= "0" && text[pos] <= "9") pos++;
-      }
-      return Number(text.slice(start, pos));
-    }
-    function readIdent() {
-      var start = pos;
-      while (pos < text.length && /[a-zA-Z0-9_~*+\-><=/!?.:&]/.test(text[pos])) pos++;
-      return text.slice(start, pos);
-    }
-    function readSymbol() {
-      var name = readIdent();
-      if (name === "true") return true;
-      if (name === "false") return false;
-      if (name === "nil") return NIL;
-      return new Symbol(name);
-    }
-    var exprs = [];
-    while (true) {
-      skipWs();
-      if (pos >= text.length) break;
-      exprs.push(readExpr());
-    }
-    return exprs;
-  }
+  // Parser — compiled from parser.sx (see PLATFORM_PARSER_JS for ident char classes)
+  var parse = sxParse;
 
   // =========================================================================
   // Public API
@@ -3104,7 +3131,7 @@ callExpr.push(dictGet(kwargs, k)); } }
     renderComponent: typeof sxRenderComponent === "function" ? sxRenderComponent : null,
     getEnv: function() { return componentEnv; },
     init: typeof bootInit === "function" ? bootInit : null,
-    _version: "ref-2.0 (boot+cssx+dom+engine+orchestration, bootstrap-compiled)"
+    _version: "ref-2.0 (boot+cssx+dom+engine+orchestration+parser, bootstrap-compiled)"
   };
 
 

shared/sx/ref/bootstrap_js.py

@@ -717,9 +717,211 @@ class JSEmitter:
 
     def _emit_define(self, expr) -> str:
         name = expr[1].name if isinstance(expr[1], Symbol) else str(expr[1])
-        val = self.emit(expr[2])
+        # Detect zero-arg self-tail-recursive functions and emit as while loops
+        fn_expr = expr[2] if len(expr) > 2 else None
+        if (fn_expr and isinstance(fn_expr, list) and fn_expr
+                and isinstance(fn_expr[0], Symbol) and fn_expr[0].name in ("fn", "lambda")
+                and isinstance(fn_expr[1], list) and len(fn_expr[1]) == 0
+                and self._is_self_tail_recursive(name, fn_expr[2:])):
+            body = fn_expr[2:]
+            loop_body = self._emit_loop_body(name, body)
+            return f"var {self._mangle(name)} = function() {{ while(true) {{ {loop_body} }} }};"
+        val = self.emit(fn_expr) if fn_expr else "NIL"
         return f"var {self._mangle(name)} = {val};"
 
+    def _is_self_tail_recursive(self, name: str, body: list) -> bool:
+        """Check if a function body contains tail calls to itself."""
+        if not body:
+            return False
+        last = body[-1]
+        return self._has_tail_call(name, last)
+
+    def _has_tail_call(self, name: str, expr) -> bool:
+        """Check if expr has a tail call to name in any branch."""
+        if not isinstance(expr, list) or not expr:
+            return False
+        head = expr[0]
+        if not isinstance(head, Symbol):
+            return False
+        h = head.name
+        # Direct tail call
+        if h == name:
+            return True
+        # Branching forms — check if any branch tail-calls
+        if h == "if":
+            return (self._has_tail_call(name, expr[2])
+                    or (len(expr) > 3 and self._has_tail_call(name, expr[3])))
+        if h == "when":
+            return any(self._has_tail_call(name, e) for e in expr[2:])
+        if h == "cond":
+            for clause in expr[1:]:
+                if isinstance(clause, list) and len(clause) == 2:
+                    if self._has_tail_call(name, clause[1]):
+                        return True
+                elif isinstance(clause, Keyword):
+                    continue
+                elif isinstance(clause, list):
+                    if self._has_tail_call(name, clause):
+                        return True
+                else:
+                    if self._has_tail_call(name, clause):
+                        return True
+            return False
+        if h in ("do", "begin"):
+            return self._has_tail_call(name, expr[-1]) if len(expr) > 1 else False
+        if h == "let" or h == "let*":
+            return self._has_tail_call(name, expr[-1]) if len(expr) > 2 else False
+        return False
+
+    def _emit_loop_body(self, name: str, body: list) -> str:
+        """Emit a function body as while-loop statements.
+
+        Replaces tail-self-calls with `continue` and non-recursive exits with
+        `return`.
+        """
+        if not body:
+            return "return NIL;"
+        # Emit side-effect statements first, then the tail expression as loop logic
+        parts = []
+        for b in body[:-1]:
+            parts.append(self.emit_statement(b))
+        parts.append(self._emit_tail_as_stmt(name, body[-1]))
+        return "\n".join(parts)
+
+    def _emit_tail_as_stmt(self, name: str, expr) -> str:
+        """Emit an expression in tail position as loop statements.
+
+        Tail-self-calls → continue; other exits → return expr;
+        """
+        if not isinstance(expr, list) or not expr:
+            return f"return {self.emit(expr)};"
+
+        head = expr[0]
+        if not isinstance(head, Symbol):
+            return f"return {self.emit(expr)};"
+
+        h = head.name
+
+        # Direct tail call to self → continue
+        if h == name:
+            return "continue;"
+
+        # (do stmt1 stmt2 ... tail) → emit stmts then recurse on tail
+        if h in ("do", "begin"):
+            stmts = []
+            for e in expr[1:-1]:
+                stmts.append(self.emit_statement(e))
+            stmts.append(self._emit_tail_as_stmt(name, expr[-1]))
+            return "\n".join(stmts)
+
+        # (if cond then else) → if/else with tail handling in each branch
+        if h == "if":
+            cond = self.emit(expr[1])
+            then_branch = self._emit_tail_as_stmt(name, expr[2])
+            else_branch = self._emit_tail_as_stmt(name, expr[3]) if len(expr) > 3 else "return NIL;"
+            return f"if (isSxTruthy({cond})) {{ {then_branch} }} else {{ {else_branch} }}"
+
+        # (when cond body...) → if (cond) { body... } else { return NIL; }
+        if h == "when":
+            cond = self.emit(expr[1])
+            body_parts = expr[2:]
+            if not body_parts:
+                return f"if (isSxTruthy({cond})) {{}} else {{ return NIL; }}"
+            stmts = []
+            for e in body_parts[:-1]:
+                stmts.append(self.emit_statement(e))
+            stmts.append(self._emit_tail_as_stmt(name, body_parts[-1]))
+            inner = "\n".join(stmts)
+            return f"if (isSxTruthy({cond})) {{ {inner} }} else {{ return NIL; }}"
+
+        # (cond clause1 clause2 ...) → if/else if/else chain
+        if h == "cond":
+            return self._emit_cond_as_loop_stmt(name, expr[1:])
+
+        # (let ((bindings)) body...) → { var ...; tail }
+        if h in ("let", "let*"):
+            bindings = expr[1]
+            body = expr[2:]
+            parts = []
+            if isinstance(bindings, list):
+                if bindings and isinstance(bindings[0], list):
+                    for b in bindings:
+                        vname = b[0].name if isinstance(b[0], Symbol) else str(b[0])
+                        parts.append(f"var {self._mangle(vname)} = {self.emit(b[1])};")
+                else:
+                    for i in range(0, len(bindings), 2):
+                        vname = bindings[i].name if isinstance(bindings[i], Symbol) else str(bindings[i])
+                        parts.append(f"var {self._mangle(vname)} = {self.emit(bindings[i + 1])};")
+            for b_expr in body[:-1]:
+                parts.append(self.emit_statement(b_expr))
+            parts.append(self._emit_tail_as_stmt(name, body[-1]))
+            inner = "\n".join(parts)
+            return f"{{ {inner} }}"
+
+        # Not a tail call to self — regular return
+        return f"return {self.emit(expr)};"
+
+    def _emit_cond_as_loop_stmt(self, name: str, clauses) -> str:
+        """Emit cond clauses as if/else if/else for loop body."""
+        if not clauses:
+            return "return NIL;"
+
+        # Detect style: Scheme vs Clojure (same as _emit_cond)
+        is_scheme = (
+            all(isinstance(c, list) and len(c) == 2 for c in clauses)
+            and not any(isinstance(c, Keyword) for c in clauses)
+        )
+        if is_scheme:
+            return self._cond_scheme_loop(name, clauses)
+        return self._cond_clojure_loop(name, clauses)
+
+    def _cond_scheme_loop(self, name: str, clauses) -> str:
+        parts = []
+        for i, clause in enumerate(clauses):
+            cond_expr = clause[0]
+            body_expr = clause[1]
+            # Check for :else / else
+            is_else = (isinstance(cond_expr, Keyword) and cond_expr.name == "else") or \
+                      (isinstance(cond_expr, Symbol) and cond_expr.name == "else") or \
+                      (isinstance(cond_expr, bool) and cond_expr is True)
+            if is_else:
+                parts.append(f"{{ {self._emit_tail_as_stmt(name, body_expr)} }}")
+                break
+            prefix = "if" if i == 0 else "else if"
+            cond = self.emit(cond_expr)
+            body = self._emit_tail_as_stmt(name, body_expr)
+            parts.append(f"{prefix} (isSxTruthy({cond})) {{ {body} }}")
+        else:
+            parts.append("else { return NIL; }")
+        return " ".join(parts)
+
+    def _cond_clojure_loop(self, name: str, clauses) -> str:
+        parts = []
+        i = 0
+        clause_idx = 0
+        has_else = False
+        while i < len(clauses):
+            c = clauses[i]
+            if isinstance(c, Keyword) and c.name == "else":
+                if i + 1 < len(clauses):
+                    parts.append(f"else {{ {self._emit_tail_as_stmt(name, clauses[i + 1])} }}")
+                    has_else = True
+                break
+            if i + 1 < len(clauses):
+                prefix = "if" if clause_idx == 0 else "else if"
+                cond = self.emit(c)
+                body = self._emit_tail_as_stmt(name, clauses[i + 1])
+                parts.append(f"{prefix} (isSxTruthy({cond})) {{ {body} }}")
+                i += 2
+            else:
+                parts.append(f"else {{ {self._emit_tail_as_stmt(name, c)} }}")
+                has_else = True
+                i += 1
+            clause_idx += 1
+        if not has_else:
+            parts.append("else { return NIL; }")
+        return " ".join(parts)
+
     def _emit_for_each_stmt(self, expr) -> str:
         fn_expr = expr[1]
         coll_expr = expr[2]
@@ -774,6 +976,7 @@ def extract_defines(source: str) -> list[tuple[str, list]]:
 
 
 ADAPTER_FILES = {
+    "parser":        ("parser.sx",       "parser"),
     "html":          ("adapter-html.sx", "adapter-html"),
     "sx":            ("adapter-sx.sx",   "adapter-sx"),
     "dom":           ("adapter-dom.sx",  "adapter-dom"),
@@ -788,7 +991,8 @@ ADAPTER_DEPS = {
     "engine": ["dom"],
     "orchestration": ["engine", "dom"],
     "cssx": [],
-    "boot": ["dom", "engine", "orchestration", "cssx"],
+    "boot": ["dom", "engine", "orchestration", "cssx", "parser"],
+    "parser": [],
 }
 
 
@@ -805,6 +1009,7 @@ def compile_ref_to_js(adapters: list[str] | None = None) -> str:
 
     # Platform JS blocks keyed by adapter name
     adapter_platform = {
+        "parser":        PLATFORM_PARSER_JS,
         "dom":           PLATFORM_DOM_JS,
         "engine":        PLATFORM_ENGINE_PURE_JS,
         "orchestration": PLATFORM_ORCHESTRATION_JS,
@@ -830,7 +1035,7 @@ def compile_ref_to_js(adapters: list[str] | None = None) -> str:
         ("eval.sx", "eval"),
         ("render.sx", "render (core)"),
     ]
-    for name in ("html", "sx", "dom", "engine", "orchestration", "cssx", "boot"):
+    for name in ("parser", "html", "sx", "dom", "engine", "orchestration", "cssx", "boot"):
         if name in adapter_set:
             sx_files.append(ADAPTER_FILES[name])
 
@@ -852,11 +1057,17 @@ def compile_ref_to_js(adapters: list[str] | None = None) -> str:
     has_orch = "orchestration" in adapter_set
     has_cssx = "cssx" in adapter_set
     has_boot = "boot" in adapter_set
+    has_parser = "parser" in adapter_set
     adapter_label = "+".join(sorted(adapter_set)) if adapter_set else "core-only"
 
     parts = []
     parts.append(PREAMBLE)
     parts.append(PLATFORM_JS)
+
+    # Parser platform must come before compiled parser.sx
+    if has_parser:
+        parts.append(adapter_platform["parser"])
+
     for label, defines in all_sections:
         parts.append(f"\n  // === Transpiled from {label} ===\n")
         for name, expr in defines:
@@ -872,7 +1083,7 @@ def compile_ref_to_js(adapters: list[str] | None = None) -> str:
             parts.append(adapter_platform[name])
 
     parts.append(fixups_js(has_html, has_sx, has_dom))
-    parts.append(public_api_js(has_html, has_sx, has_dom, has_engine, has_orch, has_cssx, has_boot, adapter_label))
+    parts.append(public_api_js(has_html, has_sx, has_dom, has_engine, has_orch, has_cssx, has_boot, has_parser, adapter_label))
     parts.append(EPILOGUE)
     return "\n".join(parts)
 
@@ -1393,6 +1604,26 @@ PLATFORM_JS = '''
     return NIL;
   }'''
 
+PLATFORM_PARSER_JS = r"""
+  // =========================================================================
+  // Platform interface — Parser
+  // =========================================================================
+  // Character classification derived from the grammar:
+  //   ident-start → [a-zA-Z_~*+\-><=/!?&]
+  //   ident-char  → ident-start + [0-9.:\/\[\]#,]
+
+  var _identStartRe = /[a-zA-Z_~*+\-><=/!?&]/;
+  var _identCharRe = /[a-zA-Z0-9_~*+\-><=/!?.:&/\[\]#,]/;
+
+  function isIdentStart(ch) { return _identStartRe.test(ch); }
+  function isIdentChar(ch) { return _identCharRe.test(ch); }
+  function parseNumber(s) { return Number(s); }
+  function escapeString(s) {
+    return s.replace(/\\/g, "\\\\").replace(/"/g, '\\"').replace(/\n/g, "\\n").replace(/\t/g, "\\t");
+  }
+  function sxExprSource(e) { return typeof e === "string" ? e : String(e); }
+"""
+
 PLATFORM_DOM_JS = """
   // =========================================================================
   // Platform interface — DOM adapter (browser-only)
@@ -2203,18 +2434,11 @@ PLATFORM_CSSX_JS = """
     if (!cssTarget) return;
 
     var rules = [];
+    // Child-selector atoms are now routed to pseudoRules by the resolver
+    // with selector ">:not(:first-child)", so base declarations are always
+    // applied directly to the class.
     if (sv.declarations) {
-      var hasChild = false;
-      if (atoms) {
-        for (var ai = 0; ai < atoms.length; ai++) {
-          if (isChildSelectorAtom(atoms[ai])) { hasChild = true; break; }
-        }
-      }
-      if (hasChild) {
-        rules.push("." + sv.className + ">:not(:first-child){" + sv.declarations + "}");
-      } else {
-        rules.push("." + sv.className + "{" + sv.declarations + "}");
-      }
+      rules.push("." + sv.className + "{" + sv.declarations + "}");
     }
     for (var pi = 0; pi < sv.pseudoRules.length; pi++) {
       var sel = sv.pseudoRules[pi][0], decls = sv.pseudoRules[pi][1];
@@ -2426,109 +2650,17 @@ def fixups_js(has_html, has_sx, has_dom):
     return "\n".join(lines)
 
 
-def public_api_js(has_html, has_sx, has_dom, has_engine, has_orch, has_cssx, has_boot, adapter_label):
-    # Parser is always included
-    parser = r'''
-  // =========================================================================
-  // Parser
-  // =========================================================================
-
+def public_api_js(has_html, has_sx, has_dom, has_engine, has_orch, has_cssx, has_boot, has_parser, adapter_label):
+    # Parser: use compiled sxParse from parser.sx, or inline a minimal fallback
+    if has_parser:
+        parser = '''
+  // Parser — compiled from parser.sx (see PLATFORM_PARSER_JS for ident char classes)
+  var parse = sxParse;'''
+    else:
+        parser = r'''
+  // Minimal fallback parser (no parser adapter)
   function parse(text) {
-    var pos = 0;
-    function skipWs() {
-      while (pos < text.length) {
-        var ch = text[pos];
-        if (ch === " " || ch === "\t" || ch === "\n" || ch === "\r") { pos++; continue; }
-        if (ch === ";") { while (pos < text.length && text[pos] !== "\n") pos++; continue; }
-        break;
-      }
-    }
-    function readExpr() {
-      skipWs();
-      if (pos >= text.length) return undefined;
-      var ch = text[pos];
-      if (ch === "(") { pos++; return readList(")"); }
-      if (ch === "[") { pos++; return readList("]"); }
-      if (ch === "{") { pos++; return readMap(); }
-      if (ch === '"') return readString();
-      if (ch === ":") return readKeyword();
-      if (ch === "`") { pos++; return [new Symbol("quasiquote"), readExpr()]; }
-      if (ch === ",") {
-        pos++;
-        if (pos < text.length && text[pos] === "@") { pos++; return [new Symbol("splice-unquote"), readExpr()]; }
-        return [new Symbol("unquote"), readExpr()];
-      }
-      if (ch === "-" && pos + 1 < text.length && text[pos + 1] >= "0" && text[pos + 1] <= "9") return readNumber();
-      if (ch >= "0" && ch <= "9") return readNumber();
-      return readSymbol();
-    }
-    function readList(close) {
-      var items = [];
-      while (true) {
-        skipWs();
-        if (pos >= text.length) throw new Error("Unterminated list");
-        if (text[pos] === close) { pos++; return items; }
-        items.push(readExpr());
-      }
-    }
-    function readMap() {
-      var result = {};
-      while (true) {
-        skipWs();
-        if (pos >= text.length) throw new Error("Unterminated map");
-        if (text[pos] === "}") { pos++; return result; }
-        var key = readExpr();
-        var keyStr = (key && key._kw) ? key.name : String(key);
-        result[keyStr] = readExpr();
-      }
-    }
-    function readString() {
-      pos++; // skip "
-      var s = "";
-      while (pos < text.length) {
-        var ch = text[pos];
-        if (ch === '"') { pos++; return s; }
-        if (ch === "\\") { pos++; var esc = text[pos]; s += esc === "n" ? "\n" : esc === "t" ? "\t" : esc === "r" ? "\r" : esc; pos++; continue; }
-        s += ch; pos++;
-      }
-      throw new Error("Unterminated string");
-    }
-    function readKeyword() {
-      pos++; // skip :
-      var name = readIdent();
-      return new Keyword(name);
-    }
-    function readNumber() {
-      var start = pos;
-      if (text[pos] === "-") pos++;
-      while (pos < text.length && text[pos] >= "0" && text[pos] <= "9") pos++;
-      if (pos < text.length && text[pos] === ".") { pos++; while (pos < text.length && text[pos] >= "0" && text[pos] <= "9") pos++; }
-      if (pos < text.length && (text[pos] === "e" || text[pos] === "E")) {
-        pos++;
-        if (pos < text.length && (text[pos] === "+" || text[pos] === "-")) pos++;
-        while (pos < text.length && text[pos] >= "0" && text[pos] <= "9") pos++;
-      }
-      return Number(text.slice(start, pos));
-    }
-    function readIdent() {
-      var start = pos;
-      while (pos < text.length && /[a-zA-Z0-9_~*+\-><=/!?.:&]/.test(text[pos])) pos++;
-      return text.slice(start, pos);
-    }
-    function readSymbol() {
-      var name = readIdent();
-      if (name === "true") return true;
-      if (name === "false") return false;
-      if (name === "nil") return NIL;
-      return new Symbol(name);
-    }
-    var exprs = [];
-    while (true) {
-      skipWs();
-      if (pos >= text.length) break;
-      exprs.push(readExpr());
-    }
-    return exprs;
+    throw new Error("Parser adapter not included — cannot parse SX source at runtime");
   }'''
 
     # Public API — conditional on adapters