Started porting JSX support from esprima-fb.

Conflicts:
	acorn.js
	test/tests.js

acorn.js

@@ -241,7 +241,7 @@
   // that `break` and `continue` have somewhere to jump to, and
   // `strict` indicates whether strict mode is on.
 
-  var inFunction, inGenerator, labels, strict;
+  var inFunction, inGenerator, labels, strict, inXJSChild, inXJSTag;
 
   // This counter is used for checking that arrow expressions did
   // not contain nested parentheses in argument list.
@@ -2015,6 +2015,11 @@
     case _bquote:
       return parseTemplate();
 
+    case _relational:
+      if (tokVal === '<') {
+        return parseXJSElement();
+      }
+
     default:
       unexpected();
     }
@@ -2526,4 +2531,148 @@
     return finishNode(node, "ComprehensionExpression");
   }
 
+  function getQualifiedXJSName(object) {
+    if (object.type === "XJSIdentifier") {
+      return object.name;
+    }
+    if (object.type === "XJSNamespacedName") {
+      return object.namespace.name + ':' + object.name.name;
+    }
+    if (object.type === "XJSMemberExpression") {
+      return (
+        getQualifiedXJSName(object.object) + '.' +
+        getQualifiedXJSName(object.property)
+      );
+    }
+  }
+
+  function parseXJSIdentifier() {
+    var node = startNode();
+    if (tokType === _name) {
+      node.name = tokVal;
+    } else {
+      unexpected();
+    }
+    tokRegexpAllowed = false;
+    next();
+    return finishNode(node, "XJSIdentifier");
+  }
+
+  function parseXJSElementName() {
+    return parseXJSIdentifier();
+  }
+
+  function parseXJSChild() {
+    /*
+    var token, marker;
+    if (tokVal === '{') {
+      token = parseXJSExpressionContainer();
+    } else if (lookahead.type === Token.XJSText) {
+      marker = markerCreatePreserveWhitespace();
+      token = markerApply(marker, delegate.createLiteral(lex()));
+    } else {
+      token = parseXJSElement();
+    }
+    return token;
+    */
+    return parseXJSElement();
+  }
+
+  function parseXJSClosingElement() {
+    var node = startNode();
+    var origInXJSChild = inXJSChild;
+    var origInXJSTag = inXJSTag;
+    inXJSChild = false;
+    inXJSTag = true;
+    tokRegexpAllowed = false;
+    tokVal === '<' ? next() : unexpected();
+    tokVal === '/' ? next() : unexpected();
+    node.name = parseXJSElementName();
+    // Because advance() (called by lex() called by expect()) expects there
+    // to be a valid token after >, it needs to know whether to look for a
+    // standard JS token or an XJS text node
+    inXJSChild = origInXJSChild;
+    inXJSTag = origInXJSTag;
+    tokVal === '>' ? next() : unexpected();
+    return finishNode(node, "XJSClosingElement");
+  }
+
+  function parseXJSOpeningElement() {
+    var node = startNode(), attributes = node.attributes = [];
+
+    var origInXJSChild = inXJSChild;
+    var origInXJSTag = inXJSTag;
+    inXJSChild = false;
+    inXJSTag = true;
+
+    tokVal === '<' ? next() : unexpected();
+
+    node.name = parseXJSElementName();
+
+    /*
+    while (index < length &&
+      lookahead.value !== '/' &&
+      lookahead.value !== '>') {
+      attributes.push(parseXJSAttribute());
+    }
+    */
+
+    inXJSTag = origInXJSTag;
+
+    if (tokType === _slash) {
+      next();
+      inXJSChild = origInXJSChild;
+      node.selfClosing = true;
+    } else {
+      inXJSChild = true;
+      node.selfClosing = false;
+    }
+    tokVal === '>' ? next() : unexpected();
+    return finishNode(node, "XJSOpeningElement");
+  }
+
+  function parseXJSElement() {
+    var node = startNode();
+    var children = [];
+
+    var origInXJSChild = inXJSChild;
+    var origInXJSTag = inXJSTag;
+    var openingElement = parseXJSOpeningElement();
+
+    if (!openingElement.selfClosing) {
+      while (tokType !== _eof) {
+        inXJSChild = false; // Call lookahead2() with inXJSChild = false because </ should not be considered in the child
+        if (tokVal === '<' && input.charAt(tokPos) === '/') {
+          break;
+        }
+        inXJSChild = true;
+        children.push(parseXJSChild());
+      }
+      inXJSChild = origInXJSChild;
+      inXJSTag = origInXJSTag;
+      var closingElement = parseXJSClosingElement();
+      if (getQualifiedXJSName(closingElement.name) !== getQualifiedXJSName(openingElement.name)) {
+        raise(tokStart, "Expected corresponding XJS closing tag for '" + getQualifiedXJSName(openingElement.name) + "'");
+      }
+    }
+
+    // When (erroneously) writing two adjacent tags like
+    //
+    //     var x = <div>one</div><div>two</div>;
+    //
+    // the default error message is a bit incomprehensible. Since it's
+    // rarely (never?) useful to write a less-than sign after an XJS
+    // element, we disallow it here in the parser in order to provide a
+    // better error message. (In the rare case that the less-than operator
+    // was intended, the left tag can be wrapped in parentheses.)
+    if (!origInXJSChild && tokVal === '<') {
+      raise(tokStart, "Adjacent XJS elements must be wrapped in an enclosing tag");
+    }
+
+    node.openingElement = openingElement;
+    node.closingElement = closingElement;
+    node.children = children;
+    return finishNode(node, "XJSElement");
+  }
+
 });

test/tests-jsx.js

@@ -0,0 +1,53 @@
+// React JSX tests
+
+if (typeof exports != "undefined") {
+  var test = require("./driver.js").test;
+  var testFail = require("./driver.js").testFail;
+  var testAssert = require("./driver.js").testAssert;
+}
+
+test('<a />', {
+  type: 'Program',
+  body: [
+    {
+      type: "ExpressionStatement",
+      expression: {
+        type: "XJSElement",
+        openingElement: {
+          type: "XJSOpeningElement",
+          name: {
+            type: "XJSIdentifier",
+            name: "a",
+            start: 1,
+            end: 2,
+            loc: {
+              start: { line: 1, column: 1 },
+              end: { line: 1, column: 2 }
+            }
+          },
+          selfClosing: true,
+          attributes: [],
+          start: 0,
+          end: 5,
+          loc: {
+            start: { line: 1, column: 0 },
+            end: { line: 1, column: 5 }
+          }
+        },
+        children: [],
+        start: 0,
+        end: 5,
+        loc: {
+          start: { line: 1, column: 0 },
+          end: { line: 1, column: 5 }
+        }
+      },
+      start: 0,
+      end: 5,
+      loc: {
+        start: { line: 1, column: 0 },
+        end: { line: 1, column: 5 }
+      }
+    }
+  ]
+}, {locations: true});

test/tests.js

@@ -6,6 +6,7 @@ if (typeof exports != "undefined") {
   var testFail = require("./driver.js").testFail;
   var testAssert = require("./driver.js").testAssert;
   var acorn = require("..");
+  require("./tests-jsx.js");
 }
 
 test("this\n", {