Java Code Examples for com.google.javascript.rhino.Token#GETELEM

/**
 * Determines if the subtree might throw an exception.
 */
public static boolean mayThrowException(Node n) {
  switch (n.getType()) {
    case Token.CALL:
    case Token.GETPROP:
    case Token.GETELEM:
    case Token.THROW:
    case Token.NEW:
    case Token.ASSIGN:
    case Token.INC:
    case Token.DEC:
    case Token.INSTANCEOF:
      return true;
    case Token.FUNCTION:
      return false;
  }
  for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
    if (!ControlFlowGraph.isEnteringNewCfgNode(c) && mayThrowException(c)) {
      return true;
    }
  }
  return false;
}
 

private void transformCallExpr(JsonML element, Node parent)
    throws JsonMLException {

  Node node = createNode(Token.CALL, element);
  parent.addChildToBack(node);

  transformAllChildren(element, node);

  // Keep track of of the "this" context of a call.  A call without an
  // explicit "this" is a free call.
  Node first = node.getFirstChild();
  if (first.getType() != Token.GETPROP && first.getType() != Token.GETELEM) {
    node.putBooleanProp(Node.FREE_CALL, true);
  }
}
 

/**
 * @param knownConstants A set of names known to be constant value at
 * node 'n' (such as locals that are last written before n can execute).
 * @return Whether the tree can be affected by side-effects or
 * has side-effects.
 */
static boolean canBeSideEffected(Node n, Set<String> knownConstants) {
  switch (n.getType()) {
    case Token.CALL:
    case Token.NEW:
      // Function calls or constructor can reference changed values.
      // TODO(johnlenz): Add some mechanism for determining that functions
      // are unaffected by side effects.
      return true;
    case Token.NAME:
      // Non-constant names values may have been changed.
      return !isConstantName(n)
          && !knownConstants.contains(n.getString());

    // Properties on constant NAMEs can still be side-effected.
    case Token.GETPROP:
    case Token.GETELEM:
      return true;

    case Token.FUNCTION:
      // Function expression are not changed by side-effects,
      // and function declarations are not part of expressions.
      Preconditions.checkState(isFunctionExpression(n));
      return false;
  }

  for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
    if (canBeSideEffected(c, knownConstants)) {
      return true;
    }
  }

  return false;
}
 

/**
 * @param knownConstants A set of names known to be constant value at
 * node 'n' (such as locals that are last written before n can execute).
 * @return Whether the tree can be affected by side-effects or
 * has side-effects.
 */
static boolean canBeSideEffected(Node n, Set<String> knownConstants) {
  switch (n.getType()) {
    case Token.CALL:
    case Token.NEW:
      // Function calls or constructor can reference changed values.
      // TODO(johnlenz): Add some mechanism for determining that functions
      // are unaffected by side effects.
      return true;
    case Token.NAME:
      // Non-constant names values may have been changed.
      return !isConstantName(n)
          && !knownConstants.contains(n.getString());

    // Properties on constant NAMEs can still be side-effected.
    case Token.GETPROP:
    case Token.GETELEM:
      return true;

    case Token.FUNCTION:
      // Function expression are not changed by side-effects,
      // and function declarations are not part of expressions.
      Preconditions.checkState(isFunctionExpression(n));
      return false;
  }

  for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
    if (canBeSideEffected(c, knownConstants)) {
      return true;
    }
  }

  return false;
}
 

/**
 * @param knownConstants A set of names known to be constant value at
 * node 'n' (such as locals that are last written before n can execute).
 * @return Whether the tree can be affected by side-effects or
 * has side-effects.
 */
static boolean canBeSideEffected(Node n, Set<String> knownConstants) {
  switch (n.getType()) {
    case Token.CALL:
    case Token.NEW:
      // Function calls or constructor can reference changed values.
      // TODO(johnlenz): Add some mechanism for determining that functions
      // are unaffected by side effects.
      return true;
    case Token.NAME:
      // Non-constant names values may have been changed.
      return !isConstantName(n)
          && !knownConstants.contains(n.getString());

    // Properties on constant NAMEs can still be side-effected.
    case Token.GETPROP:
    case Token.GETELEM:
      return true;

    case Token.FUNCTION:
      // Function expression are not changed by side-effects,
      // and function declarations are not part of expressions.
      Preconditions.checkState(isFunctionExpression(n));
      return false;
  }

  for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
    if (canBeSideEffected(c, knownConstants)) {
      return true;
    }
  }

  return false;
}
 

@Override
public void visit(NodeTraversal t, Node n, Node parent) {
  switch (n.getType()) {
    case Token.GETPROP:
    case Token.GETELEM:
      Node dest = n.getFirstChild().getNext();
      if (dest.isString()) {
        String s = dest.getString();
        if (s.equals("prototype")) {
          processPrototypeParent(parent, t.getInput());
        } else {
          markPropertyAccessCandidate(dest, t.getInput());
        }
      }
      break;
    case Token.OBJECTLIT:
      if (!prototypeObjLits.contains(n)) {
        // Object literals have their property name/value pairs as a flat
        // list as their children. We want every other node in order to get
        // only the property names.
        for (Node child = n.getFirstChild();
             child != null;
             child = child.getNext()) {

          if (TokenStream.isJSIdentifier(child.getString())) {
            markObjLitPropertyCandidate(child, t.getInput());
          }
        }
      }
      break;
  }
}
 

/**
 * This predicate is used to determine if the node represents an expression
 * that is a Reference according to JavaScript definitions.
 *
 * @param n The node being checked.
 * @return true if the sub-tree n is a reference, false otherwise.
 */
private static boolean isReference(Node n) {
  switch (n.getType()) {
    case Token.GETELEM:
    case Token.GETPROP:
    case Token.NAME:
      return true;

    default:
      return false;
  }

}
 

static int precedence(int type) {
  switch (type) {
    case Token.COMMA:  return 0;
    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
    case Token.ASSIGN: return 1;
    case Token.HOOK:   return 2;  // ?: operator
    case Token.OR:     return 3;
    case Token.AND:    return 4;
    case Token.BITOR:  return 5;
    case Token.BITXOR: return 6;
    case Token.BITAND: return 7;
    case Token.EQ:
    case Token.NE:
    case Token.SHEQ:
    case Token.SHNE:   return 8;
    case Token.LT:
    case Token.GT:
    case Token.LE:
    case Token.GE:
    case Token.INSTANCEOF:
    case Token.IN:     return 9;
    case Token.LSH:
    case Token.RSH:
    case Token.URSH:   return 10;
    case Token.SUB:
    case Token.ADD:    return 11;
    case Token.MUL:
    case Token.MOD:
    case Token.DIV:    return 12;
    case Token.INC:
    case Token.DEC:
    case Token.NEW:
    case Token.DELPROP:
    case Token.TYPEOF:
    case Token.VOID:
    case Token.NOT:
    case Token.BITNOT:
    case Token.POS:
    case Token.NEG:    return 13;

    case Token.ARRAYLIT:
    case Token.CALL:
    case Token.EMPTY:
    case Token.FALSE:
    case Token.FUNCTION:
    case Token.GETELEM:
    case Token.GETPROP:
    case Token.GET_REF:
    case Token.IF:
    case Token.LP:
    case Token.NAME:
    case Token.NULL:
    case Token.NUMBER:
    case Token.OBJECTLIT:
    case Token.REGEXP:
    case Token.STRING:
    case Token.THIS:
    case Token.TRUE:
      return 15;

    default: throw new Error("Unknown precedence for " +
                             Node.tokenToName(type) +
                             " (type " + type + ")");
  }
}
 

/**
 * Returns a qualified name of the specified node. Dots and brackets
 * are changed to the delimiter passed in when constructing the
 * NodeNameExtractor object.  We also replace ".prototype" with the
 * delimiter to keep names short, while still differentiating them
 * from static properties.  (Prototype properties will end up
 * looking like "a$b$$c" if this.delimiter = '$'.)
 */
String getName(Node node) {
  switch (node.getType()) {
    case Token.FUNCTION:
      Node functionNameNode = node.getFirstChild();
      return functionNameNode.getString();
    case Token.GETPROP:
      Node lhsOfDot = node.getFirstChild();
      Node rhsOfDot = lhsOfDot.getNext();
      String lhsOfDotName = getName(lhsOfDot);
      String rhsOfDotName = getName(rhsOfDot);
      if ("prototype".equals(rhsOfDotName)) {
        return lhsOfDotName + delimiter;
      } else {
        return lhsOfDotName + delimiter + rhsOfDotName;
      }
    case Token.GETELEM:
      Node outsideBrackets = node.getFirstChild();
      Node insideBrackets = outsideBrackets.getNext();
      String nameOutsideBrackets = getName(outsideBrackets);
      String nameInsideBrackets = getName(insideBrackets);
      if ("prototype".equals(nameInsideBrackets)) {
        return nameOutsideBrackets + delimiter;
      } else {
        return nameOutsideBrackets + delimiter + nameInsideBrackets;
      }
    case Token.NAME:
      return node.getString();
    case Token.STRING:
    case Token.STRING_KEY:
      return TokenStream.isJSIdentifier(node.getString()) ?
          node.getString() : ("__" + nextUniqueInt++);
    case Token.NUMBER:
      return NodeUtil.getStringValue(node);
    case Token.THIS:
      return "this";
    case Token.CALL:
      return getName(node.getFirstChild());
    default:
      StringBuilder sb = new StringBuilder();
      for (Node child = node.getFirstChild(); child != null;
           child = child.getNext()) {
        if (sb.length() > 0) {
          sb.append(delimiter);
        }
        sb.append(getName(child));
      }
      return sb.toString();
  }
}
 

static int precedence(int type) {
  switch (type) {
    case Token.COMMA:  return 0;
    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
    case Token.ASSIGN: return 1;
    case Token.HOOK:   return 2;  // ?: operator
    case Token.OR:     return 3;
    case Token.AND:    return 4;
    case Token.BITOR:  return 5;
    case Token.BITXOR: return 6;
    case Token.BITAND: return 7;
    case Token.EQ:
    case Token.NE:
    case Token.SHEQ:
    case Token.SHNE:   return 8;
    case Token.LT:
    case Token.GT:
    case Token.LE:
    case Token.GE:
    case Token.INSTANCEOF:
    case Token.IN:     return 9;
    case Token.LSH:
    case Token.RSH:
    case Token.URSH:   return 10;
    case Token.SUB:
    case Token.ADD:    return 11;
    case Token.MUL:
    case Token.MOD:
    case Token.DIV:    return 12;
    case Token.INC:
    case Token.DEC:
    case Token.NEW:
    case Token.DELPROP:
    case Token.TYPEOF:
    case Token.VOID:
    case Token.NOT:
    case Token.BITNOT:
    case Token.POS:
    case Token.NEG:    return 13;

    case Token.CALL:
    case Token.GETELEM:
    case Token.GETPROP:
    // Data values
    case Token.ARRAYLIT:
    case Token.EMPTY:  // TODO(johnlenz): remove this.
    case Token.FALSE:
    case Token.FUNCTION:
    case Token.NAME:
    case Token.NULL:
    case Token.NUMBER:
    case Token.OBJECTLIT:
    case Token.REGEXP:
    case Token.STRING:
    case Token.STRING_KEY:
    case Token.THIS:
    case Token.TRUE:
      return 15;

    default: throw new Error("Unknown precedence for " +
                             Token.name(type) +
                             " (type " + type + ")");
  }
}
 

static int precedence(int type) {
  switch (type) {
    case Token.COMMA:  return 0;
    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
    case Token.ASSIGN: return 1;
    case Token.HOOK:   return 2;  // ?: operator
    case Token.OR:     return 3;
    case Token.AND:    return 4;
    case Token.BITOR:  return 5;
    case Token.BITXOR: return 6;
    case Token.BITAND: return 7;
    case Token.EQ:
    case Token.NE:
    case Token.SHEQ:
    case Token.SHNE:   return 8;
    case Token.LT:
    case Token.GT:
    case Token.LE:
    case Token.GE:
    case Token.INSTANCEOF:
    case Token.IN:     return 9;
    case Token.LSH:
    case Token.RSH:
    case Token.URSH:   return 10;
    case Token.SUB:
    case Token.ADD:    return 11;
    case Token.MUL:
    case Token.MOD:
    case Token.DIV:    return 12;
    case Token.INC:
    case Token.DEC:
    case Token.NEW:
    case Token.DELPROP:
    case Token.TYPEOF:
    case Token.VOID:
    case Token.NOT:
    case Token.BITNOT:
    case Token.POS:
    case Token.NEG:    return 13;

    case Token.ARRAYLIT:
    case Token.CALL:
    case Token.EMPTY:
    case Token.FALSE:
    case Token.FUNCTION:
    case Token.GETELEM:
    case Token.GETPROP:
    case Token.GET_REF:
    case Token.IF:
    case Token.LP:
    case Token.NAME:
    case Token.NULL:
    case Token.NUMBER:
    case Token.OBJECTLIT:
    case Token.REGEXP:
    case Token.RETURN:
    case Token.STRING:
    case Token.THIS:
    case Token.TRUE:
      return 15;

    default: throw new Error("Unknown precedence for " +
                             Node.tokenToName(type) +
                             " (type " + type + ")");
  }
}
 

static int precedence(int type) {
  switch (type) {
    case Token.COMMA:  return 0;
    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
    case Token.ASSIGN: return 1;
    case Token.HOOK:   return 2;  // ?: operator
    case Token.OR:     return 3;
    case Token.AND:    return 4;
    case Token.BITOR:  return 5;
    case Token.BITXOR: return 6;
    case Token.BITAND: return 7;
    case Token.EQ:
    case Token.NE:
    case Token.SHEQ:
    case Token.SHNE:   return 8;
    case Token.LT:
    case Token.GT:
    case Token.LE:
    case Token.GE:
    case Token.INSTANCEOF:
    case Token.IN:     return 9;
    case Token.LSH:
    case Token.RSH:
    case Token.URSH:   return 10;
    case Token.SUB:
    case Token.ADD:    return 11;
    case Token.MUL:
    case Token.MOD:
    case Token.DIV:    return 12;
    case Token.INC:
    case Token.DEC:
    case Token.NEW:
    case Token.DELPROP:
    case Token.TYPEOF:
    case Token.VOID:
    case Token.NOT:
    case Token.BITNOT:
    case Token.POS:
    case Token.NEG:    return 13;

    case Token.ARRAYLIT:
    case Token.CALL:
    case Token.EMPTY:
    case Token.FALSE:
    case Token.FUNCTION:
    case Token.GETELEM:
    case Token.GETPROP:
    case Token.GET_REF:
    case Token.IF:
    case Token.LP:
    case Token.NAME:
    case Token.NULL:
    case Token.NUMBER:
    case Token.OBJECTLIT:
    case Token.REGEXP:
    case Token.RETURN:
    case Token.STRING:
    case Token.THIS:
    case Token.TRUE:
      return 15;

    default: throw new Error("Unknown precedence for " +
                             Node.tokenToName(type) +
                             " (type " + type + ")");
  }
}
 

/**
 * Is this a GETPROP or GETELEM node?
 */
static boolean isGet(Node n) {
  return n.getType() == Token.GETPROP
      || n.getType() == Token.GETELEM;
}
 

static int precedence(int type) {
  switch (type) {
    case Token.COMMA:  return 0;
    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
    case Token.ASSIGN: return 1;
    case Token.HOOK:   return 2;  // ?: operator
    case Token.OR:     return 3;
    case Token.AND:    return 4;
    case Token.BITOR:  return 5;
    case Token.BITXOR: return 6;
    case Token.BITAND: return 7;
    case Token.EQ:
    case Token.NE:
    case Token.SHEQ:
    case Token.SHNE:   return 8;
    case Token.LT:
    case Token.GT:
    case Token.LE:
    case Token.GE:
    case Token.INSTANCEOF:
    case Token.IN:     return 9;
    case Token.LSH:
    case Token.RSH:
    case Token.URSH:   return 10;
    case Token.SUB:
    case Token.ADD:    return 11;
    case Token.MUL:
    case Token.MOD:
    case Token.DIV:    return 12;
    case Token.INC:
    case Token.DEC:
    case Token.NEW:
    case Token.DELPROP:
    case Token.TYPEOF:
    case Token.VOID:
    case Token.NOT:
    case Token.BITNOT:
    case Token.POS:
    case Token.NEG:    return 13;

    case Token.CALL:
    case Token.GETELEM:
    case Token.GETPROP:
    // Data values
    case Token.ARRAYLIT:
    case Token.EMPTY:  // TODO(johnlenz): remove this.
    case Token.FALSE:
    case Token.FUNCTION:
    case Token.NAME:
    case Token.NULL:
    case Token.NUMBER:
    case Token.OBJECTLIT:
    case Token.REGEXP:
    case Token.STRING:
    case Token.STRING_KEY:
    case Token.THIS:
    case Token.TRUE:
      return 15;

    default: throw new Error("Unknown precedence for " +
                             Token.name(type) +
                             " (type " + type + ")");
  }
}
 

/**
 * Removes a reference if it is a reference to a removed variable.
 *
 * @param t The traversal
 * @param n A NAME node
 * @param parent {@code n}'s parent
 */
void maybeRemoveReferenceToRemovedVariable(NodeTraversal t, Node n,
                                           Node parent) {
  switch (parent.getType()) {
    case Token.VAR:
      // This is a variable declaration, not a reference.
      break;

    case Token.GETPROP:
      // GETPROP
      //   NAME
      //   STRING (property name)
    case Token.GETELEM:
      // GETELEM
      //   NAME
      //   NUMBER|STRING|NAME|...
      if (parent.getFirstChild() == n && isReferenceToRemovedVar(t, n)) {
        replaceHighestNestedCallWithNull(parent, parent.getParent());
      }
      break;

    case Token.ASSIGN:
    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
      if (isReferenceToRemovedVar(t, n)) {
        if (parent.getFirstChild() == n) {
          Node gramps = parent.getParent();
          if (gramps.isExprResult()) {
            // Remove the assignment.
            Node greatGramps = gramps.getParent();
            replaceWithEmpty(gramps, greatGramps);
            compiler.reportCodeChange();
          } else {
            // Substitute the r-value for the assignment.
            Node rvalue = n.getNext();
            parent.removeChild(rvalue);
            gramps.replaceChild(parent, rvalue);
            compiler.reportCodeChange();
          }
        } else {
          // The var reference is the r-value. Replace it with null.
          replaceWithNull(n, parent);
          compiler.reportCodeChange();
        }
      }
      break;

    default:
      if (isReferenceToRemovedVar(t, n)) {
        replaceWithNull(n, parent);
        compiler.reportCodeChange();
      }
      break;
  }
}
 

/**
 * Is this a GETPROP or GETELEM node?
 */
static boolean isGet(Node n) {
  return n.getType() == Token.GETPROP
      || n.getType() == Token.GETELEM;
}
 

private Node tryFoldBinaryOperator(Node subtree) {
  Node left = subtree.getFirstChild();

  if (left == null) {
    return subtree;
  }

  Node right = left.getNext();

  if (right == null) {
    return subtree;
  }

  // If we've reached here, node is truly a binary operator.
  switch(subtree.getType()) {
    case Token.GETPROP:
      return tryFoldGetProp(subtree, left, right);

    case Token.GETELEM:
      return tryFoldGetElem(subtree, left, right);

    case Token.INSTANCEOF:
      return tryFoldInstanceof(subtree, left, right);

    case Token.AND:
    case Token.OR:
      return tryFoldAndOr(subtree, left, right);

    case Token.LSH:
    case Token.RSH:
    case Token.URSH:
      return tryFoldShift(subtree, left, right);

    case Token.ASSIGN:
      return tryFoldAssign(subtree, left, right);

    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
      return tryUnfoldAssignOp(subtree, left, right);

    case Token.ADD:
      return tryFoldAdd(subtree, left, right);

    case Token.SUB:
    case Token.DIV:
    case Token.MOD:
      return tryFoldArithmeticOp(subtree, left, right);

    case Token.MUL:
    case Token.BITAND:
    case Token.BITOR:
    case Token.BITXOR:
      Node result = tryFoldArithmeticOp(subtree, left, right);
      if (result != subtree) {
        return result;
      }
      return tryFoldLeftChildOp(subtree, left, right);

    case Token.LT:
    case Token.GT:
    case Token.LE:
    case Token.GE:
    case Token.EQ:
    case Token.NE:
    case Token.SHEQ:
    case Token.SHNE:
      return tryFoldComparison(subtree, left, right);

    default:
      return subtree;
  }
}
 

static int precedence(int type) {
  switch (type) {
    case Token.COMMA:  return 0;
    case Token.ASSIGN_BITOR:
    case Token.ASSIGN_BITXOR:
    case Token.ASSIGN_BITAND:
    case Token.ASSIGN_LSH:
    case Token.ASSIGN_RSH:
    case Token.ASSIGN_URSH:
    case Token.ASSIGN_ADD:
    case Token.ASSIGN_SUB:
    case Token.ASSIGN_MUL:
    case Token.ASSIGN_DIV:
    case Token.ASSIGN_MOD:
    case Token.ASSIGN: return 1;
    case Token.HOOK:   return 2;  // ?: operator
    case Token.OR:     return 3;
    case Token.AND:    return 4;
    case Token.BITOR:  return 5;
    case Token.BITXOR: return 6;
    case Token.BITAND: return 7;
    case Token.EQ:
    case Token.NE:
    case Token.SHEQ:
    case Token.SHNE:   return 8;
    case Token.LT:
    case Token.GT:
    case Token.LE:
    case Token.GE:
    case Token.INSTANCEOF:
    case Token.IN:     return 9;
    case Token.LSH:
    case Token.RSH:
    case Token.URSH:   return 10;
    case Token.SUB:
    case Token.ADD:    return 11;
    case Token.MUL:
    case Token.MOD:
    case Token.DIV:    return 12;
    case Token.INC:
    case Token.DEC:
    case Token.NEW:
    case Token.DELPROP:
    case Token.TYPEOF:
    case Token.VOID:
    case Token.NOT:
    case Token.BITNOT:
    case Token.POS:
    case Token.NEG:    return 13;

    case Token.CALL:
    case Token.GETELEM:
    case Token.GETPROP:
    // Data values
    case Token.ARRAYLIT:
    case Token.EMPTY:  // TODO(johnlenz): remove this.
    case Token.FALSE:
    case Token.FUNCTION:
    case Token.NAME:
    case Token.NULL:
    case Token.NUMBER:
    case Token.OBJECTLIT:
    case Token.REGEXP:
    case Token.STRING:
    case Token.STRING_KEY:
    case Token.THIS:
    case Token.TRUE:
      return 15;

    default: throw new Error("Unknown precedence for " +
                             Token.name(type) +
                             " (type " + type + ")");
  }
}
 

/**
 * @param locals A predicate to apply to unknown local values.
 * @return Whether the node is known to be a value that is not a reference
 *     outside the expression scope.
 */
static boolean evaluatesToLocalValue(Node value, Predicate<Node> locals) {
  switch (value.getType()) {
    case Token.ASSIGN:
      // A result that is aliased by a non-local name, is the effectively the
      // same as returning a non-local name, but this doesn't matter if the
      // value is immutable.
      return NodeUtil.isImmutableValue(value.getLastChild())
          || (locals.apply(value)
              && evaluatesToLocalValue(value.getLastChild(), locals));
    case Token.COMMA:
      return evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.AND:
    case Token.OR:
      return evaluatesToLocalValue(value.getFirstChild(), locals)
         && evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.HOOK:
      return evaluatesToLocalValue(value.getFirstChild().getNext(), locals)
         && evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.INC:
    case Token.DEC:
      if (value.getBooleanProp(Node.INCRDECR_PROP)) {
        return evaluatesToLocalValue(value.getFirstChild(), locals);
      } else {
        return true;
      }
    case Token.THIS:
      return locals.apply(value);
    case Token.NAME:
      return isImmutableValue(value) || locals.apply(value);
    case Token.GETELEM:
    case Token.GETPROP:
      // There is no information about the locality of object properties.
      return locals.apply(value);
    case Token.CALL:
      return callHasLocalResult(value)
          || isToStringMethodCall(value)
          || locals.apply(value);
    case Token.NEW:
      return newHasLocalResult(value)
             || locals.apply(value);
    case Token.FUNCTION:
    case Token.REGEXP:
    case Token.ARRAYLIT:
    case Token.OBJECTLIT:
      // Literals objects with non-literal children are allowed.
      return true;
    case Token.DELPROP:
    case Token.IN:
      // TODO(johnlenz): should IN operator be included in #isSimpleOperator?
      return true;
    default:
      // Other op force a local value:
      //  x = '' + g (x is now an local string)
      //  x -= g (x is now an local number)
      if (isAssignmentOp(value)
          || isSimpleOperator(value)
          || isImmutableValue(value)) {
        return true;
      }

      throw new IllegalStateException(
          "Unexpected expression node" + value +
          "\n parent:" + value.getParent());
  }
}
 

/**
 * @param locals A predicate to apply to unknown local values.
 * @return Whether the node is known to be a value that is not a reference
 *     outside the expression scope.
 */
static boolean evaluatesToLocalValue(Node value, Predicate<Node> locals) {
  switch (value.getType()) {
    case Token.ASSIGN:
      // A result that is aliased by a non-local name, is the effectively the
      // same as returning a non-local name, but this doesn't matter if the
      // value is immutable.
      return NodeUtil.isImmutableValue(value.getLastChild())
          || (locals.apply(value)
              && evaluatesToLocalValue(value.getLastChild(), locals));
    case Token.COMMA:
      return evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.AND:
    case Token.OR:
      return evaluatesToLocalValue(value.getFirstChild(), locals)
         && evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.HOOK:
      return evaluatesToLocalValue(value.getFirstChild().getNext(), locals)
         && evaluatesToLocalValue(value.getLastChild(), locals);
    case Token.INC:
    case Token.DEC:
      if (value.getBooleanProp(Node.INCRDECR_PROP)) {
        return evaluatesToLocalValue(value.getFirstChild(), locals);
      } else {
        return true;
      }
    case Token.THIS:
      return locals.apply(value);
    case Token.NAME:
      return isImmutableValue(value) || locals.apply(value);
    case Token.GETELEM:
    case Token.GETPROP:
      // There is no information about the locality of object properties.
      return locals.apply(value);
    case Token.CALL:
      return callHasLocalResult(value)
          || isToStringMethodCall(value)
          || locals.apply(value);
    case Token.NEW:
      return newHasLocalResult(value)
             || locals.apply(value);
    case Token.FUNCTION:
    case Token.REGEXP:
    case Token.ARRAYLIT:
    case Token.OBJECTLIT:
      // Literals objects with non-literal children are allowed.
      return true;
    case Token.DELPROP:
    case Token.IN:
      // TODO(johnlenz): should IN operator be included in #isSimpleOperator?
      return true;
    default:
      // Other op force a local value:
      //  x = '' + g (x is now an local string)
      //  x -= g (x is now an local number)
      if (isAssignmentOp(value)
          || isSimpleOperator(value)
          || isImmutableValue(value)) {
        return true;
      }

      throw new IllegalStateException(
          "Unexpected expression node" + value +
          "\n parent:" + value.getParent());
  }
}