diff --git a/dist/.keep b/dist/.keep
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/src/loose/acorn_loose.js b/src/loose/acorn_loose.js
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/src/loose/expression.js b/src/loose/expression.js
new file mode 100644
index 0000000000..ff38374b94
--- /dev/null
+++ b/src/loose/expression.js
@@ -0,0 +1,603 @@
+import {LooseParser} from "./state"
+import {isDummy} from "./parseutil"
+import {tokTypes as tt} from ".."
+
+const lp = LooseParser.prototype
+
+lp.checkLVal = function(expr) {
+  if (!expr) return expr;
+  switch (expr.type) {
+  case "Identifier":
+  case "MemberExpression":
+  case "ObjectPattern":
+  case "ArrayPattern":
+  case "RestElement":
+  case "AssignmentPattern":
+    return expr;
+
+  default:
+    return this.dummyIdent();
+  }
+};
+
+lp.parseExpression = function(noIn) {
+  var start = this.storeCurrentPos();
+  var expr = this.parseMaybeAssign(noIn);
+  if (this.tok.type === tt.comma) {
+    var node = this.startNodeAt(start);
+    node.expressions = [expr];
+    while (this.eat(tt.comma)) node.expressions.push(this.parseMaybeAssign(noIn));
+    return this.finishNode(node, "SequenceExpression");
+  }
+  return expr;
+};
+
+lp.parseParenExpression = function() {
+  this.pushCx();
+  this.expect(tt.parenL);
+  var val = this.parseExpression();
+  this.popCx();
+  this.expect(tt.parenR);
+  return val;
+};
+
+lp.parseMaybeAssign = function(noIn) {
+  var start = this.storeCurrentPos();
+  var left = this.parseMaybeConditional(noIn);
+  if (this.tok.type.isAssign) {
+    var node = this.startNodeAt(start);
+    node.operator = this.tok.value;
+    node.left = this.tok.type === tt.eq ? this.toAssignable(left) : this.checkLVal(left);
+    this.next();
+    node.right = this.parseMaybeAssign(noIn);
+    return this.finishNode(node, "AssignmentExpression");
+  }
+  return left;
+};
+
+lp.parseMaybeConditional = function(noIn) {
+  var start = this.storeCurrentPos();
+  var expr = this.parseExprOps(noIn);
+  if (this.eat(tt.question)) {
+    var node = this.startNodeAt(start);
+    node.test = expr;
+    node.consequent = this.parseMaybeAssign();
+    node.alternate = this.expect(tt.colon) ? this.parseMaybeAssign(noIn) : this.dummyIdent();
+    return this.finishNode(node, "ConditionalExpression");
+  }
+  return expr;
+};
+
+lp.parseExprOps = function(noIn) {
+  var start = this.storeCurrentPos();
+  var indent = this.curIndent, line = this.curLineStart;
+  return this.parseExprOp(this.parseMaybeUnary(noIn), start, -1, noIn, indent, line);
+};
+
+lp.parseExprOp = function(left, start, minPrec, noIn, indent, line) {
+  if (this.curLineStart != line && this.curIndent < indent && this.tokenStartsLine()) return left;
+  var prec = this.tok.type.binop;
+  if (prec != null && (!noIn || this.tok.type !== tt._in)) {
+    if (prec > minPrec) {
+      var node = this.startNodeAt(start);
+      node.left = left;
+      node.operator = this.tok.value;
+      this.next();
+      if (this.curLineStart != line && this.curIndent < indent && this.tokenStartsLine()) {
+        node.right = this.dummyIdent();
+      } else {
+        var rightStart = this.storeCurrentPos();
+        node.right = this.parseExprOp(this.parseMaybeUnary(noIn), rightStart, prec, noIn, indent, line);
+      }
+      this.finishNode(node, /&&|\|\|/.test(node.operator) ? "LogicalExpression" : "BinaryExpression");
+      return this.parseExprOp(node, start, minPrec, noIn, indent, line);
+    }
+  }
+  return left;
+};
+
+lp.parseMaybeUnary = function(noIn) {
+  if (this.tok.type.prefix) {
+    var node = this.startNode(), update = this.tok.type === tt.incDec;
+    node.operator = this.tok.value;
+    node.prefix = true;
+    this.next();
+    node.argument = this.parseMaybeUnary(noIn);
+    if (update) node.argument = this.checkLVal(node.argument);
+    return this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression");
+  } else if (this.tok.type === tt.ellipsis) {
+    var node = this.startNode();
+    this.next();
+    node.argument = this.parseMaybeUnary(noIn);
+    return this.finishNode(node, "SpreadElement");
+  }
+  var start = this.storeCurrentPos();
+  var expr = this.parseExprSubscripts();
+  while (this.tok.type.postfix && !this.canInsertSemicolon()) {
+    var node = this.startNodeAt(start);
+    node.operator = this.tok.value;
+    node.prefix = false;
+    node.argument = this.checkLVal(expr);
+    this.next();
+    expr = this.finishNode(node, "UpdateExpression");
+  }
+  return expr;
+};
+
+lp.parseExprSubscripts = function() {
+  var start = this.storeCurrentPos();
+  return this.parseSubscripts(this.parseExprAtom(), start, false, this.curIndent, this.curLineStart);
+};
+
+lp.parseSubscripts = function(base, start, noCalls, startIndent, line) {
+  for (;;) {
+    if (this.curLineStart != line && this.curIndent <= startIndent && this.tokenStartsLine()) {
+      if (this.tok.type == tt.dot && this.curIndent == startIndent)
+        --startIndent;
+      else
+        return base;
+    }
+
+    if (this.eat(tt.dot)) {
+      var node = this.startNodeAt(start);
+      node.object = base;
+      if (this.curLineStart != line && this.curIndent <= startIndent && this.tokenStartsLine())
+        node.property = this.dummyIdent();
+      else
+        node.property = this.parsePropertyAccessor() || this.dummyIdent();
+      node.computed = false;
+      base = this.finishNode(node, "MemberExpression");
+    } else if (this.tok.type == tt.bracketL) {
+      this.pushCx();
+      this.next();
+      var node = this.startNodeAt(start);
+      node.object = base;
+      node.property = this.parseExpression();
+      node.computed = true;
+      this.popCx();
+      this.expect(tt.bracketR);
+      base = this.finishNode(node, "MemberExpression");
+    } else if (!noCalls && this.tok.type == tt.parenL) {
+      this.pushCx();
+      var node = this.startNodeAt(start);
+      node.callee = base;
+      node.arguments = this.parseExprList(tt.parenR);
+      base = this.finishNode(node, "CallExpression");
+    } else if (this.tok.type == tt.backQuote) {
+      var node = this.startNodeAt(start);
+      node.tag = base;
+      node.quasi = this.parseTemplate();
+      base = this.finishNode(node, "TaggedTemplateExpression");
+    } else {
+      return base;
+    }
+  }
+};
+
+lp.parseExprAtom = function() {
+  switch (this.tok.type) {
+  case tt._this:
+  case tt._super:
+    var type = this.tok.type === tt._this ? "ThisExpression" : "SuperExpression";
+    var node = this.startNode();
+    this.next();
+    return this.finishNode(node, type);
+
+  case tt.name:
+    var start = this.storeCurrentPos();
+    var id = this.parseIdent();
+    return this.eat(tt.arrow) ? this.parseArrowExpression(this.startNodeAt(start), [id]) : id;
+
+  case tt.regexp:
+    var node = this.startNode();
+    var val = this.tok.value;
+    node.regex = {pattern: val.pattern, flags: val.flags};
+    node.value = val.value;
+    node.raw = this.input.slice(this.tok.start, this.tok.end);
+    this.next();
+    return this.finishNode(node, "Literal");
+
+  case tt.num: case tt.string:
+    var node = this.startNode();
+    node.value = this.tok.value;
+    node.raw = this.input.slice(this.tok.start, this.tok.end);
+    this.next();
+    return this.finishNode(node, "Literal");
+
+  case tt._null: case tt._true: case tt._false:
+    var node = this.startNode();
+    node.value = this.tok.type === tt._null ? null : this.tok.type === tt._true;
+    node.raw = this.tok.type.keyword;
+    this.next();
+    return this.finishNode(node, "Literal");
+
+  case tt.parenL:
+    var start = this.storeCurrentPos();
+    this.next();
+    var val = this.parseExpression();
+    this.expect(tt.parenR);
+    if (this.eat(tt.arrow)) {
+      return this.parseArrowExpression(this.startNodeAt(start), val.expressions || (isDummy(val) ? [] : [val]));
+    }
+    if (this.options.preserveParens) {
+      var par = this.startNodeAt(start);
+      par.expression = val;
+      val = this.finishNode(par, "ParenthesizedExpression");
+    }
+    return val;
+
+  case tt.bracketL:
+    var node = this.startNode();
+    this.pushCx();
+    node.elements = this.parseExprList(tt.bracketR, true);
+    return this.finishNode(node, "ArrayExpression");
+
+  case tt.braceL:
+    return this.parseObj();
+
+  case tt._class:
+    return this.parseClass();
+
+  case tt._function:
+    var node = this.startNode();
+    this.next();
+    return this.parseFunction(node, false);
+
+  case tt._new:
+    return this.parseNew();
+
+  case tt._yield:
+    var node = this.startNode();
+    this.next();
+    if (this.semicolon() || this.canInsertSemicolon() || (this.tok.type != tt.star && !this.tok.type.startsExpr)) {
+      node.delegate = false;
+      node.argument = null;
+    } else {
+      node.delegate = this.eat(tt.star);
+      node.argument = this.parseMaybeAssign();
+    }
+    return this.finishNode(node, "YieldExpression");
+
+  case tt.backQuote:
+    return this.parseTemplate();
+
+  default:
+    return this.dummyIdent();
+  }
+};
+
+lp.parseNew = function() {
+  var node = this.startNode(), startIndent = this.curIndent, line = this.curLineStart;
+  this.next();
+  var start = this.storeCurrentPos();
+  node.callee = this.parseSubscripts(this.parseExprAtom(), start, true, startIndent, line);
+  if (this.tok.type == tt.parenL) {
+    this.pushCx();
+    node.arguments = this.parseExprList(tt.parenR);
+  } else {
+    node.arguments = [];
+  }
+  return this.finishNode(node, "NewExpression");
+};
+
+lp.parseTemplateElement = function() {
+  var elem = this.startNode();
+  elem.value = {
+    raw: this.input.slice(this.tok.start, this.tok.end),
+    cooked: this.tok.value
+  };
+  this.next();
+  elem.tail = this.tok.type === tt.backQuote;
+  return this.finishNode(elem, "TemplateElement");
+};
+
+lp.parseTemplate = function() {
+  var node = this.startNode();
+  this.next();
+  node.expressions = [];
+  var curElt = this.parseTemplateElement();
+  node.quasis = [curElt];
+  while (!curElt.tail) {
+    this.next();
+    node.expressions.push(this.parseExpression());
+    if (this.expect(tt.braceR)) {
+      curElt = this.parseTemplateElement();
+    } else {
+      curElt = this.startNode();
+      curElt.value = {cooked: '', raw: ''};
+      curElt.tail = true;
+    }
+    node.quasis.push(curElt);
+  }
+  this.expect(tt.backQuote);
+  return this.finishNode(node, "TemplateLiteral");
+};
+
+lp.parseObj = function() {
+  var node = this.startNode();
+  node.properties = [];
+  this.pushCx();
+  var indent = this.curIndent + 1, line = this.curLineStart;
+  this.eat(tt.braceL);
+  if (this.curIndent + 1 < indent) { indent = this.curIndent; line = this.curLineStart; }
+  while (!this.closes(tt.braceR, indent, line)) {
+    var prop = this.startNode(), isGenerator, start;
+    if (this.options.ecmaVersion >= 6) {
+      start = this.storeCurrentPos();
+      prop.method = false;
+      prop.shorthand = false;
+      isGenerator = this.eat(tt.star);
+    }
+    this.parsePropertyName(prop);
+    if (isDummy(prop.key)) { if (isDummy(this.parseMaybeAssign())) this.next(); this.eat(tt.comma); continue; }
+    if (this.eat(tt.colon)) {
+      prop.kind = "init";
+      prop.value = this.parseMaybeAssign();
+    } else if (this.options.ecmaVersion >= 6 && (this.tok.type === tt.parenL || this.tok.type === tt.braceL)) {
+      prop.kind = "init";
+      prop.method = true;
+      prop.value = this.parseMethod(isGenerator);
+    } else if (this.options.ecmaVersion >= 5 && prop.key.type === "Identifier" &&
+               !prop.computed && (prop.key.name === "get" || prop.key.name === "set") &&
+               (this.tok.type != tt.comma && this.tok.type != tt.braceR)) {
+      prop.kind = prop.key.name;
+      this.parsePropertyName(prop);
+      prop.value = this.parseMethod(false);
+    } else {
+      prop.kind = "init";
+      if (this.options.ecmaVersion >= 6) {
+        if (this.eat(tt.eq)) {
+          var assign = this.startNodeAt(start);
+          assign.operator = "=";
+          assign.left = prop.key;
+          assign.right = this.parseMaybeAssign();
+          prop.value = this.finishNode(assign, "AssignmentExpression");
+        } else {
+          prop.value = prop.key;
+        }
+      } else {
+        prop.value = this.dummyIdent();
+      }
+      prop.shorthand = true;
+    }
+    node.properties.push(this.finishNode(prop, "Property"));
+    this.eat(tt.comma);
+  }
+  this.popCx();
+  if (!this.eat(tt.braceR)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) this.last.loc.end = this.tok.loc.start;
+  }
+  return this.finishNode(node, "ObjectExpression");
+};
+
+lp.parsePropertyName = function(prop) {
+  if (this.options.ecmaVersion >= 6) {
+    if (this.eat(tt.bracketL)) {
+      prop.computed = true;
+      prop.key = this.parseExpression();
+      this.expect(tt.bracketR);
+      return;
+    } else {
+      prop.computed = false;
+    }
+  }
+  var key = (this.tok.type === tt.num || this.tok.type === tt.string) ? this.parseExprAtom() : this.parseIdent();
+  prop.key = key || this.dummyIdent();
+};
+
+lp.parsePropertyAccessor = function() {
+  if (this.tok.type === tt.name || this.tok.type.keyword) return this.parseIdent();
+};
+
+lp.parseIdent = function() {
+  var node = this.startNode();
+  node.name = this.tok.type === tt.name ? this.tok.value : this.tok.type.keyword;
+  this.next();
+  return this.finishNode(node, "Identifier");
+};
+
+lp.initFunction = function(node) {
+  node.id = null;
+  node.params = [];
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = false;
+    node.expression = false;
+  }
+};
+
+// Convert existing expression atom to assignable pattern
+// if possible.
+
+lp.toAssignable = function(node) {
+  if (this.options.ecmaVersion >= 6 && node) {
+    switch (node.type) {
+    case "ObjectExpression":
+      node.type = "ObjectPattern";
+      var props = node.properties;
+      for (var i = 0; i < props.length; i++)
+        this.toAssignable(props[i].value);
+      break;
+
+    case "ArrayExpression":
+      node.type = "ArrayPattern";
+      this.toAssignableList(node.elements);
+      break;
+
+    case "SpreadElement":
+      node.type = "RestElement";
+      node.argument = this.toAssignable(node.argument);
+      break;
+
+    case "AssignmentExpression":
+      node.type = "AssignmentPattern";
+      break;
+    }
+  }
+  return this.checkLVal(node);
+};
+
+lp.toAssignableList = function(exprList) {
+  for (var i = 0; i < exprList.length; i++)
+    this.toAssignable(exprList[i]);
+  return exprList;
+};
+
+lp.parseFunctionParams = function(params) {
+  this.pushCx();
+  params = this.parseExprList(tt.parenR);
+  return this.toAssignableList(params);
+};
+
+lp.parseMethod = function(isGenerator) {
+  var node = this.startNode();
+  this.initFunction(node);
+  node.params = this.parseFunctionParams();
+  node.generator = isGenerator || false;
+  node.expression = this.options.ecmaVersion >= 6 && this.tok.type !== tt.braceL;
+  node.body = node.expression ? this.parseMaybeAssign() : this.parseBlock();
+  return this.finishNode(node, "FunctionExpression");
+};
+
+lp.parseArrowExpression = function(node, params) {
+  this.initFunction(node);
+  node.params = this.toAssignableList(params);
+  node.expression = this.tok.type !== tt.braceL;
+  node.body = node.expression ? this.parseMaybeAssign() : this.parseBlock();
+  return this.finishNode(node, "ArrowFunctionExpression");
+};
+
+lp.parseExport = function() {
+  var node = this.startNode();
+  this.next();
+  if (this.eat(tt.star)) {
+    node.source = this.eatContextual("from") ? this.parseExprAtom() : null;
+    return this.finishNode(node, "ExportAllDeclaration");
+  }
+  if (this.eat(tt._default)) {
+    var expr = this.parseMaybeAssign();
+    if (expr.id) {
+      switch (expr.type) {
+      case "FunctionExpression": expr.type = "FunctionDeclaration"; break;
+      case "ClassExpression": expr.type = "ClassDeclaration"; break;
+      }
+    }
+    node.declaration = expr;
+    this.semicolon();
+    return this.finishNode(node, "ExportDefaultDeclaration");
+  }
+  if (this.tok.type.keyword) {
+    node.declaration = this.parseStatement();
+    node.specifiers = [];
+    node.source = null;
+  } else {
+    node.declaration = null;
+    node.specifiers = this.parseExportSpecifierList();
+    node.source = this.eatContextual("from") ? this.parseExprAtom() : null;
+    this.semicolon();
+  }
+  return this.finishNode(node, "ExportNamedDeclaration");
+};
+
+lp.parseImport = function() {
+  var node = this.startNode();
+  this.next();
+  if (this.tok.type === tt.string) {
+    node.specifiers = [];
+    node.source = this.parseExprAtom();
+    node.kind = '';
+  } else {
+    if (this.tok.type === tt.name && this.tok.value !== "from") {
+      var elt = this.startNode();
+      elt.local = this.parseIdent();
+      this.finishNode(elt, "ImportDefaultSpecifier");
+      this.eat(tt.comma);
+    }
+    node.specifiers = this.parseImportSpecifierList();
+    node.source = this.eatContextual("from") ? this.parseExprAtom() : null;
+    if (elt) node.specifiers.unshift(elt);
+  }
+  this.semicolon();
+  return this.finishNode(node, "ImportDeclaration");
+};
+
+lp.parseImportSpecifierList = function() {
+  var elts = [];
+  if (this.tok.type === tt.star) {
+    var elt = this.startNode();
+    this.next();
+    if (this.eatContextual("as")) elt.local = this.parseIdent();
+    elts.push(this.finishNode(elt, "ImportNamespaceSpecifier"));
+  } else {
+    var indent = this.curIndent, line = this.curLineStart, continuedLine = this.nextLineStart;
+    this.pushCx();
+    this.eat(tt.braceL);
+    if (this.curLineStart > continuedLine) continuedLine = this.curLineStart;
+    while (!this.closes(tt.braceR, indent + (this.curLineStart <= continuedLine ? 1 : 0), line)) {
+      var elt = this.startNode();
+      if (this.eat(tt.star)) {
+        if (this.eatContextual("as")) elt.local = this.parseIdent();
+        this.finishNode(elt, "ImportNamespaceSpecifier");
+      } else {
+        if (this.isContextual("from")) break;
+        elt.imported = this.parseIdent();
+        elt.local = this.eatContextual("as") ? this.parseIdent() : elt.imported;
+        this.finishNode(elt, "ImportSpecifier");
+      }
+      elts.push(elt);
+      this.eat(tt.comma);
+    }
+    this.eat(tt.braceR);
+    this.popCx();
+  }
+  return elts;
+};
+
+lp.parseExportSpecifierList = function() {
+  var elts = [];
+  var indent = this.curIndent, line = this.curLineStart, continuedLine = this.nextLineStart;
+  this.pushCx();
+  this.eat(tt.braceL);
+  if (this.curLineStart > continuedLine) continuedLine = this.curLineStart;
+  while (!this.closes(tt.braceR, indent + (this.curLineStart <= continuedLine ? 1 : 0), line)) {
+    if (this.isContextual("from")) break;
+    var elt = this.startNode();
+    elt.local = this.parseIdent();
+    elt.exported = this.eatContextual("as") ? this.parseIdent() : elt.local;
+    this.finishNode(elt, "ExportSpecifier");
+    elts.push(elt);
+    this.eat(tt.comma);
+  }
+  this.eat(tt.braceR);
+  this.popCx();
+  return elts;
+};
+
+lp.parseExprList = function(close, allowEmpty) {
+  var indent = this.curIndent, line = this.curLineStart, elts = [];
+  this.next(); // Opening bracket
+  while (!this.closes(close, indent + 1, line)) {
+    if (this.eat(tt.comma)) {
+      elts.push(allowEmpty ? null : this.dummyIdent());
+      continue;
+    }
+    var elt = this.parseMaybeAssign();
+    if (isDummy(elt)) {
+      if (this.closes(close, indent, line)) break;
+      this.next();
+    } else {
+      elts.push(elt);
+    }
+    this.eat(tt.comma);
+  }
+  this.popCx();
+  if (!this.eat(close)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) this.last.loc.end = this.tok.loc.start;
+  }
+  return elts;
+};
diff --git a/src/loose/index.js b/src/loose/index.js
new file mode 100644
index 0000000000..acbea8a6c3
--- /dev/null
+++ b/src/loose/index.js
@@ -0,0 +1,50 @@
+// Acorn: Loose parser
+//
+// This module provides an alternative parser (`parse_dammit`) that
+// exposes that same interface as `parse`, but will try to parse
+// anything as JavaScript, repairing syntax error the best it can.
+// There are circumstances in which it will raise an error and give
+// up, but they are very rare. The resulting AST will be a mostly
+// valid JavaScript AST (as per the [Mozilla parser API][api], except
+// that:
+//
+// - Return outside functions is allowed
+//
+// - Label consistency (no conflicts, break only to existing labels)
+//   is not enforced.
+//
+// - Bogus Identifier nodes with a name of `"✖"` are inserted whenever
+//   the parser got too confused to return anything meaningful.
+//
+// [api]: https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API
+//
+// The expected use for this is to *first* try `acorn.parse`, and only
+// if that fails switch to `parse_dammit`. The loose parser might
+// parse badly indented code incorrectly, so **don't** use it as
+// your default parser.
+//
+// Quite a lot of acorn.js is duplicated here. The alternative was to
+// add a *lot* of extra cruft to that file, making it less readable
+// and slower. Copying and editing the code allowed me to make
+// invasive changes and simplifications without creating a complicated
+// tangle.
+
+import * as acorn from ".."
+import {LooseParser} from "./state"
+import "./tokenize"
+import "./parseutil"
+import "./statement"
+import "./expression"
+
+export {LooseParser} from "./state"
+
+acorn.defaultOptions.tabSize = 4
+
+export function parse_dammit(input, options) {
+  let p = new LooseParser(input, options)
+  p.next()
+  return p.parseTopLevel()
+}
+
+acorn.parse_dammit = parse_dammit
+acorn.LooseParser = LooseParser
diff --git a/src/loose/parseutil.js b/src/loose/parseutil.js
new file mode 100644
index 0000000000..5f656ec282
--- /dev/null
+++ b/src/loose/parseutil.js
@@ -0,0 +1,126 @@
+import {LooseParser} from "./state"
+import {Node, SourceLocation, lineBreak, isNewLine, tokTypes as tt} from ".."
+
+const lp = LooseParser.prototype
+
+lp.startNode = function() {
+  var node = new Node;
+  node.start = this.tok.start;
+  if (this.options.locations)
+    node.loc = new SourceLocation(this.toks, this.tok.loc.start);
+  if (this.options.directSourceFile)
+    node.sourceFile = this.options.directSourceFile;
+  if (this.options.ranges)
+    node.range = [this.tok.start, 0];
+  return node;
+};
+
+lp.storeCurrentPos = function() {
+  return this.options.locations ? [this.tok.start, this.tok.loc.start] : this.tok.start;
+};
+
+lp.startNodeAt = function(pos) {
+  var node = new Node;
+  if (this.options.locations) {
+    node.start = pos[0];
+    node.loc = new SourceLocation(this.toks, pos[1]);
+    pos = pos[0];
+  } else {
+    node.start = pos;
+  }
+  if (this.options.directSourceFile)
+    node.sourceFile = this.options.directSourceFile;
+  if (this.options.ranges)
+    node.range = [pos, 0];
+  return node;
+};
+
+lp.finishNode = function(node, type) {
+  node.type = type;
+  node.end = this.last.end;
+  if (this.options.locations)
+    node.loc.end = this.last.loc.end;
+  if (this.options.ranges)
+    node.range[1] = this.last.end;
+  return node;
+};
+
+lp.dummyIdent = function() {
+  var dummy = this.startNode();
+  dummy.name = "✖";
+  return this.finishNode(dummy, "Identifier");
+};
+
+export function isDummy(node) { return node.name == "✖"; }
+
+lp.eat = function(type) {
+  if (this.tok.type === type) {
+    this.next();
+    return true;
+  } else {
+    return false;
+  }
+};
+
+lp.isContextual = function(name) {
+  return this.tok.type === tt.name && this.tok.value === name;
+};
+
+lp.eatContextual = function(name) {
+  return this.tok.value === name && this.eat(tt.name);
+};
+
+lp.canInsertSemicolon = function() {
+  return this.tok.type === tt.eof || this.tok.type === tt.braceR ||
+    lineBreak.test(this.input.slice(this.last.end, this.tok.start));
+};
+
+lp.semicolon = function() {
+  return this.eat(tt.semi);
+};
+
+lp.expect = function(type) {
+  if (this.eat(type)) return true;
+  for (var i = 1; i <= 2; i++) {
+    if (this.lookAhead(i).type == type) {
+      for (var j = 0; j < i; j++) this.next();
+      return true;
+    }
+  }
+};
+
+lp.pushCx = function() {
+  this.context.push(this.curIndent);
+};
+lp.popCx = function() {
+  this.curIndent = this.context.pop();
+};
+
+lp.lineEnd = function(pos) {
+  while (pos < this.input.length && !isNewLine(this.input.charCodeAt(pos))) ++pos;
+  return pos;
+};
+
+lp.indentationAfter = function(pos) {
+  for (var count = 0;; ++pos) {
+    var ch = this.input.charCodeAt(pos);
+    if (ch === 32) ++count;
+    else if (ch === 9) count += this.options.tabSize;
+    else return count;
+  }
+};
+
+lp.closes = function(closeTok, indent, line, blockHeuristic) {
+  if (this.tok.type === closeTok || this.tok.type === tt.eof) return true;
+  return line != this.curLineStart && this.curIndent < indent && this.tokenStartsLine() &&
+    (!blockHeuristic || this.nextLineStart >= this.input.length ||
+     this.indentationAfter(this.nextLineStart) < indent);
+};
+
+lp.tokenStartsLine = function() {
+  for (var p = this.tok.start - 1; p >= this.curLineStart; --p) {
+    var ch = this.input.charCodeAt(p);
+    if (ch !== 9 && ch !== 32) return false;
+  }
+  return true;
+};
diff --git a/src/loose/state.js b/src/loose/state.js
new file mode 100644
index 0000000000..3854da2261
--- /dev/null
+++ b/src/loose/state.js
@@ -0,0 +1,17 @@
+import {tokenizer, SourceLocation, tokTypes as tt} from ".."
+
+export function LooseParser(input, options) {
+  this.toks = tokenizer(input, options)
+  this.options = this.toks.options;
+  this.input = this.toks.input;
+  this.tok = this.last = {type: tt.eof, start: 0, end: 0};
+  if (this.options.locations) {
+    var here = this.toks.curPosition();
+    this.tok.loc = new SourceLocation(this.toks, here, here);
+  }
+  this.ahead = []; // Tokens ahead
+  this.context = []; // Indentation contexted
+  this.curIndent = 0;
+  this.curLineStart = 0;
+  this.nextLineStart = this.lineEnd(this.curLineStart) + 1;
+}
diff --git a/src/loose/statement.js b/src/loose/statement.js
new file mode 100644
index 0000000000..ad7257da21
--- /dev/null
+++ b/src/loose/statement.js
@@ -0,0 +1,311 @@
+import {LooseParser} from "./state"
+import {isDummy} from "./parseutil"
+import {getLineInfo, tokTypes as tt} from ".."
+
+const lp = LooseParser.prototype
+
+lp.parseTopLevel = function() {
+  var node = this.startNodeAt(this.options.locations ? [0, acorn.getLineInfo(this.input, 0)] : 0);
+  node.body = [];
+  while (this.tok.type !== tt.eof) node.body.push(this.parseStatement());
+  this.last = this.tok;
+  if (this.options.ecmaVersion >= 6) {
+    node.sourceType = this.options.sourceType;
+  }
+  return this.finishNode(node, "Program");
+};
+
+lp.parseStatement = function() {
+  var starttype = this.tok.type, node = this.startNode();
+
+  switch (starttype) {
+  case tt._break: case tt._continue:
+    this.next();
+    var isBreak = starttype === tt._break;
+    if (this.semicolon() || this.canInsertSemicolon()) {
+      node.label = null;
+    } else {
+      node.label = this.tok.type === tt.name ? this.parseIdent() : null;
+      this.semicolon();
+    }
+    return this.finishNode(node, isBreak ? "BreakStatement" : "ContinueStatement");
+
+  case tt._debugger:
+    this.next();
+    this.semicolon();
+    return this.finishNode(node, "DebuggerStatement");
+
+  case tt._do:
+    this.next();
+    node.body = this.parseStatement();
+    node.test = this.eat(tt._while) ? this.parseParenExpression() : this.dummyIdent();
+    this.semicolon();
+    return this.finishNode(node, "DoWhileStatement");
+
+  case tt._for:
+    this.next();
+    this.pushCx();
+    this.expect(tt.parenL);
+    if (this.tok.type === tt.semi) return this.parseFor(node, null);
+    if (this.tok.type === tt._var || this.tok.type === tt._let || this.tok.type === tt._const) {
+      var init = this.parseVar(true);
+      if (init.declarations.length === 1 && (this.tok.type === tt._in || this.isContextual("of"))) {
+        return this.parseForIn(node, init);
+      }
+      return this.parseFor(node, init);
+    }
+    var init = this.parseExpression(true);
+    if (this.tok.type === tt._in || this.isContextual("of"))
+      return this.parseForIn(node, this.toAssignable(init));
+    return this.parseFor(node, init);
+
+  case tt._function:
+    this.next();
+    return this.parseFunction(node, true);
+
+  case tt._if:
+    this.next();
+    node.test = this.parseParenExpression();
+    node.consequent = this.parseStatement();
+    node.alternate = this.eat(tt._else) ? this.parseStatement() : null;
+    return this.finishNode(node, "IfStatement");
+
+  case tt._return:
+    this.next();
+    if (this.eat(tt.semi) || this.canInsertSemicolon()) node.argument = null;
+    else { node.argument = this.parseExpression(); this.semicolon(); }
+    return this.finishNode(node, "ReturnStatement");
+
+  case tt._switch:
+    var blockIndent = this.curIndent, line = this.curLineStart;
+    this.next();
+    node.discriminant = this.parseParenExpression();
+    node.cases = [];
+    this.pushCx();
+    this.expect(tt.braceL);
+
+    for (var cur; !this.closes(tt.braceR, blockIndent, line, true);) {
+      if (this.tok.type === tt._case || this.tok.type === tt._default) {
+        var isCase = this.tok.type === tt._case;
+        if (cur) this.finishNode(cur, "SwitchCase");
+        node.cases.push(cur = this.startNode());
+        cur.consequent = [];
+        this.next();
+        if (isCase) cur.test = this.parseExpression();
+        else cur.test = null;
+        this.expect(tt.colon);
+      } else {
+        if (!cur) {
+          node.cases.push(cur = this.startNode());
+          cur.consequent = [];
+          cur.test = null;
+        }
+        cur.consequent.push(this.parseStatement());
+      }
+    }
+    if (cur) this.finishNode(cur, "SwitchCase");
+    this.popCx();
+    this.eat(tt.braceR);
+    return this.finishNode(node, "SwitchStatement");
+
+  case tt._throw:
+    this.next();
+    node.argument = this.parseExpression();
+    this.semicolon();
+    return this.finishNode(node, "ThrowStatement");
+
+  case tt._try:
+    this.next();
+    node.block = this.parseBlock();
+    node.handler = null;
+    if (this.tok.type === tt._catch) {
+      var clause = this.startNode();
+      this.next();
+      this.expect(tt.parenL);
+      clause.param = this.toAssignable(this.parseExprAtom());
+      this.expect(tt.parenR);
+      clause.guard = null;
+      clause.body = this.parseBlock();
+      node.handler = this.finishNode(clause, "CatchClause");
+    }
+    node.finalizer = this.eat(tt._finally) ? this.parseBlock() : null;
+    if (!node.handler && !node.finalizer) return node.block;
+    return this.finishNode(node, "TryStatement");
+
+  case tt._var:
+  case tt._let:
+  case tt._const:
+    return this.parseVar();
+
+  case tt._while:
+    this.next();
+    node.test = this.parseParenExpression();
+    node.body = this.parseStatement();
+    return this.finishNode(node, "WhileStatement");
+
+  case tt._with:
+    this.next();
+    node.object = this.parseParenExpression();
+    node.body = this.parseStatement();
+    return this.finishNode(node, "WithStatement");
+
+  case tt.braceL:
+    return this.parseBlock();
+
+  case tt.semi:
+    this.next();
+    return this.finishNode(node, "EmptyStatement");
+
+  case tt._class:
+    return this.parseClass(true);
+
+  case tt._import:
+    return this.parseImport();
+
+  case tt._export:
+    return this.parseExport();
+
+  default:
+    var expr = this.parseExpression();
+    if (isDummy(expr)) {
+      this.next();
+      if (this.tok.type === tt.eof) return this.finishNode(node, "EmptyStatement");
+      return this.parseStatement();
+    } else if (starttype === tt.name && expr.type === "Identifier" && this.eat(tt.colon)) {
+      node.body = this.parseStatement();
+      node.label = expr;
+      return this.finishNode(node, "LabeledStatement");
+    } else {
+      node.expression = expr;
+      this.semicolon();
+      return this.finishNode(node, "ExpressionStatement");
+    }
+  }
+};
+
+lp.parseBlock = function() {
+  var node = this.startNode();
+  this.pushCx();
+  this.expect(tt.braceL);
+  var blockIndent = this.curIndent, line = this.curLineStart;
+  node.body = [];
+  while (!this.closes(tt.braceR, blockIndent, line, true))
+    node.body.push(this.parseStatement());
+  this.popCx();
+  this.eat(tt.braceR);
+  return this.finishNode(node, "BlockStatement");
+};
+
+lp.parseFor = function(node, init) {
+  node.init = init;
+  node.test = node.update = null;
+  if (this.eat(tt.semi) && this.tok.type !== tt.semi) node.test = this.parseExpression();
+  if (this.eat(tt.semi) && this.tok.type !== tt.parenR) node.update = this.parseExpression();
+  this.popCx();
+  this.expect(tt.parenR);
+  node.body = this.parseStatement();
+  return this.finishNode(node, "ForStatement");
+};
+
+lp.parseForIn = function(node, init) {
+  var type = this.tok.type === tt._in ? "ForInStatement" : "ForOfStatement";
+  this.next();
+  node.left = init;
+  node.right = this.parseExpression();
+  this.popCx();
+  this.expect(tt.parenR);
+  node.body = this.parseStatement();
+  return this.finishNode(node, type);
+};
+
+lp.parseVar = function(noIn) {
+  var node = this.startNode();
+  node.kind = this.tok.type.keyword;
+  this.next();
+  node.declarations = [];
+  do {
+    var decl = this.startNode();
+    decl.id = this.options.ecmaVersion >= 6 ? this.toAssignable(this.parseExprAtom()) : this.parseIdent();
+    decl.init = this.eat(tt.eq) ? this.parseMaybeAssign(noIn) : null;
+    node.declarations.push(this.finishNode(decl, "VariableDeclarator"));
+  } while (this.eat(tt.comma));
+  if (!node.declarations.length) {
+    var decl = this.startNode();
+    decl.id = this.dummyIdent();
+    node.declarations.push(this.finishNode(decl, "VariableDeclarator"));
+  }
+  if (!noIn) this.semicolon();
+  return this.finishNode(node, "VariableDeclaration");
+};
+
+lp.parseClass = function(isStatement) {
+  var node = this.startNode();
+  this.next();
+  if (this.tok.type === tt.name) node.id = this.parseIdent();
+  else if (isStatement) node.id = this.dummyIdent();
+  else node.id = null;
+  node.superClass = this.eat(tt._extends) ? this.parseExpression() : null;
+  node.body = this.startNode();
+  node.body.body = [];
+  this.pushCx();
+  var indent = this.curIndent + 1, line = this.curLineStart;
+  this.eat(tt.braceL);
+  if (this.curIndent + 1 < indent) { indent = this.curIndent; line = this.curLineStart; }
+  while (!this.closes(tt.braceR, indent, line)) {
+    if (this.semicolon()) continue;
+    var method = this.startNode(), isGenerator, start;
+    if (this.options.ecmaVersion >= 6) {
+      method['static'] = false;
+      isGenerator = this.eat(tt.star);
+    }
+    this.parsePropertyName(method);
+    if (isDummy(method.key)) { if (isDummy(this.parseMaybeAssign())) this.next(); this.eat(tt.comma); continue; }
+    if (method.key.type === "Identifier" && !method.computed && method.key.name === "static" &&
+        (this.tok.type != tt.parenL && this.tok.type != tt.braceL)) {
+      method['static'] = true;
+      isGenerator = this.eat(tt.star);
+      this.parsePropertyName(method);
+    } else {
+      method['static'] = false;
+    }
+    if (this.options.ecmaVersion >= 5 && method.key.type === "Identifier" &&
+        !method.computed && (method.key.name === "get" || method.key.name === "set") &&
+        this.tok.type !== tt.parenL && this.tok.type !== tt.braceL) {
+      method.kind = method.key.name;
+      this.parsePropertyName(method);
+      method.value = this.parseMethod(false);
+    } else {
+      if (!method.computed && !method['static'] && !isGenerator && (
+        method.key.type === "Identifier" && method.key.name === "constructor" ||
+          method.key.type === "Literal" && method.key.value === "constructor")) {
+        method.kind = "constructor";
+      } else {
+        method.kind =  "method";
+      }
+      method.value = this.parseMethod(isGenerator);
+    }
+    node.body.body.push(this.finishNode(method, "MethodDefinition"));
+  }
+  this.popCx();
+  if (!this.eat(tt.braceR)) {
+    // If there is no closing brace, make the node span to the start
+    // of the next token (this is useful for Tern)
+    this.last.end = this.tok.start;
+    if (this.options.locations) this.last.loc.end = this.tok.loc.start;
+  }
+  this.semicolon();
+  this.finishNode(node.body, "ClassBody");
+  return this.finishNode(node, isStatement ? "ClassDeclaration" : "ClassExpression");
+};
+
+lp.parseFunction = function(node, isStatement) {
+  this.initFunction(node);
+  if (this.options.ecmaVersion >= 6) {
+    node.generator = this.eat(tt.star);
+  }
+  if (this.tok.type === tt.name) node.id = this.parseIdent();
+  else if (isStatement) node.id = this.dummyIdent();
+  node.params = this.parseFunctionParams();
+  node.body = this.parseBlock();
+  return this.finishNode(node, isStatement ? "FunctionDeclaration" : "FunctionExpression");
+};
diff --git a/src/loose/tokenize.js b/src/loose/tokenize.js
new file mode 100644
index 0000000000..ba3d14a8df
--- /dev/null
+++ b/src/loose/tokenize.js
@@ -0,0 +1,108 @@
+import {tokTypes as tt, Token, isNewLine, SourceLocation, getLineInfo, lineBreakG} from ".."
+import {LooseParser} from "./state"
+
+const lp = LooseParser.prototype
+
+function isSpace(ch) {
+  return (ch < 14 && ch > 8) || ch === 32 || ch === 160 || isNewLine(ch)
+}
+
+lp.next = function() {
+  this.last = this.tok;
+  if (this.ahead.length)
+    this.tok = this.ahead.shift();
+  else
+    this.tok = this.readToken();
+
+  if (this.tok.start >= this.nextLineStart) {
+    while (this.tok.start >= this.nextLineStart) {
+      this.curLineStart = this.nextLineStart;
+      this.nextLineStart = this.lineEnd(this.curLineStart) + 1;
+    }
+    this.curIndent = this.indentationAfter(this.curLineStart);
+  }
+};
+
+lp.readToken = function() {
+  for (;;) {
+    try {
+      this.toks.next();
+      if (this.toks.type === tt.dot &&
+          this.input.substr(this.toks.end, 1) === "." &&
+          this.options.ecmaVersion >= 6) {
+        this.toks.end++;
+        this.toks.type = tt.ellipsis;
+      }
+      return new Token(this.toks);
+    } catch(e) {
+      if (!(e instanceof SyntaxError)) throw e;
+
+      // Try to skip some text, based on the error message, and then continue
+      var msg = e.message, pos = e.raisedAt, replace = true;
+      if (/unterminated/i.test(msg)) {
+        pos = this.lineEnd(e.pos + 1);
+        if (/string/.test(msg)) {
+          replace = {start: e.pos, end: pos, type: tt.string, value: this.input.slice(e.pos + 1, pos)};
+        } else if (/regular expr/i.test(msg)) {
+          var re = this.input.slice(e.pos, pos);
+          try { re = new RegExp(re); } catch(e) {}
+          replace = {start: e.pos, end: pos, type: tt.regexp, value: re};
+        } else if (/template/.test(msg)) {
+          replace = {start: e.pos, end: pos,
+                     type: tt.template,
+                     value: this.input.slice(e.pos, pos)};
+        } else {
+          replace = false;
+        }
+      } else if (/invalid (unicode|regexp|number)|expecting unicode|octal literal|is reserved|directly after number/i.test(msg)) {
+        while (pos < this.input.length && !isSpace(this.input.charCodeAt(pos))) ++pos;
+      } else if (/character escape|expected hexadecimal/i.test(msg)) {
+        while (pos < this.input.length) {
+          var ch = this.input.charCodeAt(pos++);
+          if (ch === 34 || ch === 39 || isNewLine(ch)) break;
+        }
+      } else if (/unexpected character/i.test(msg)) {
+        pos++;
+        replace = false;
+      } else if (/regular expression/i.test(msg)) {
+        replace = true;
+      } else {
+        throw e;
+      }
+      this.resetTo(pos);
+      if (replace === true) replace = {start: pos, end: pos, type: tt.name, value: "✖"};
+      if (replace) {
+        if (this.options.locations)
+          replace.loc = new SourceLocation(
+            this.toks,
+            getLineInfo(this.input, replace.start),
+            getLineInfo(this.input, replace.end));
+        return replace;
+      }
+    }
+  }
+};
+
+lp.resetTo = function(pos) {
+  this.toks.pos = pos;
+  var ch = this.input.charAt(pos - 1);
+  this.toks.exprAllowed = !ch || /[\[\{\(,;:?\/*=+\-~!|&%^<>]/.test(ch) ||
+    /[enwfd]/.test(ch) &&
+    /\b(keywords|case|else|return|throw|new|in|(instance|type)of|delete|void)$/.test(this.input.slice(pos - 10, pos));
+
+  if (this.options.locations) {
+    this.toks.curLine = 1;
+    this.toks.lineStart = lineBreakG.lastIndex = 0;
+    var match;
+    while ((match = lineBreakG.exec(this.input)) && match.index < pos) {
+      ++this.toks.curLine;
+      this.toks.lineStart = match.index + match[0].length;
+    }
+  }
+};
+
+lp.lookAhead = function(n) {
+  while (n > this.ahead.length)
+    this.ahead.push(this.readToken());
+  return this.ahead[n - 1];
+};
diff --git a/tools/build-acorn.js b/tools/build-acorn.js
new file mode 100644
index 0000000000..01a3ef11c8
--- /dev/null
+++ b/tools/build-acorn.js
@@ -0,0 +1,40 @@
+var fs = require("fs"), path = require("path")
+var stream = require("stream")
+
+var browserify = require("browserify")
+var babelify = require("babelify")
+
+process.chdir(path.resolve(__dirname, ".."))
+
+browserify({standalone: "acorn"})
+  .transform(babelify)
+  .require("./src/index.js", {entry: true})
+  .bundle()
+  .on("error", function (err) { console.log("Error: " + err.message) })
+  .pipe(fs.createWriteStream("dist/acorn.js"))
+
+function acornShim(file) {
+  var tr = new stream.Transform
+  if (file == path.resolve(__dirname, "../src/index.js")) {
+    var sent = false
+    tr._transform = function(chunk, _, callback) {
+      if (!sent) {
+        sent = true
+        callback(null, "module.exports = typeof window != 'undefined' ? window.acorn : require(('suppress', './acorn'))")
+      } else {
+        callback()
+      }
+    }
+  } else {
+    tr._transform = function(chunk, _, callback) { callback(null, chunk) }
+  }
+  return tr
+}
+
+browserify()
+  .transform(acornShim)
+  .transform(babelify)
+  .require("./src/loose/index.js", {entry: true})
+  .bundle()
+  .on("error", function (err) { console.log("Error: " + err.message) })
+  .pipe(fs.createWriteStream("dist/acorn_loose.js"))