jdk8-mips64-public/nashorn: src/jdk/nashorn/internal/parser/Parser.java@85e3f07fc5fc (annotated)

src/jdk/nashorn/internal/parser/Parser.java@85e3f07fc5fc (annotated)

src/jdk/nashorn/internal/parser/Parser.java

Tue, 26 Aug 2014 11:31:31 +0200

author: attila
date: Tue, 26 Aug 2014 11:31:31 +0200
changeset 975: 85e3f07fc5fc
parent 963: e2497b11a021
child 977: 7cf80b2dc39b
permissions: -rw-r--r--

8055911: Don't use String.intern for IdentNode
Reviewed-by: lagergren, sundar

 /*
  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 package jdk.nashorn.internal.parser;
 import static jdk.nashorn.internal.codegen.CompilerConstants.ANON_FUNCTION_PREFIX;
 import static jdk.nashorn.internal.codegen.CompilerConstants.EVAL;
 import static jdk.nashorn.internal.codegen.CompilerConstants.PROGRAM;
 import static jdk.nashorn.internal.parser.TokenType.ASSIGN;
 import static jdk.nashorn.internal.parser.TokenType.CASE;
 import static jdk.nashorn.internal.parser.TokenType.CATCH;
 import static jdk.nashorn.internal.parser.TokenType.COLON;
 import static jdk.nashorn.internal.parser.TokenType.COMMARIGHT;
 import static jdk.nashorn.internal.parser.TokenType.CONST;
 import static jdk.nashorn.internal.parser.TokenType.DECPOSTFIX;
 import static jdk.nashorn.internal.parser.TokenType.DECPREFIX;
 import static jdk.nashorn.internal.parser.TokenType.ELSE;
 import static jdk.nashorn.internal.parser.TokenType.EOF;
 import static jdk.nashorn.internal.parser.TokenType.EOL;
 import static jdk.nashorn.internal.parser.TokenType.FINALLY;
 import static jdk.nashorn.internal.parser.TokenType.FUNCTION;
 import static jdk.nashorn.internal.parser.TokenType.IDENT;
 import static jdk.nashorn.internal.parser.TokenType.IF;
 import static jdk.nashorn.internal.parser.TokenType.INCPOSTFIX;
 import static jdk.nashorn.internal.parser.TokenType.LBRACE;
 import static jdk.nashorn.internal.parser.TokenType.LPAREN;
 import static jdk.nashorn.internal.parser.TokenType.RBRACE;
 import static jdk.nashorn.internal.parser.TokenType.RBRACKET;
 import static jdk.nashorn.internal.parser.TokenType.RPAREN;
 import static jdk.nashorn.internal.parser.TokenType.SEMICOLON;
 import static jdk.nashorn.internal.parser.TokenType.TERNARY;
 import static jdk.nashorn.internal.parser.TokenType.WHILE;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Deque;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import jdk.internal.dynalink.support.NameCodec;
 import jdk.nashorn.internal.codegen.CompilerConstants;
 import jdk.nashorn.internal.codegen.Namespace;
 import jdk.nashorn.internal.ir.AccessNode;
 import jdk.nashorn.internal.ir.BaseNode;
 import jdk.nashorn.internal.ir.BinaryNode;
 import jdk.nashorn.internal.ir.Block;
 import jdk.nashorn.internal.ir.BlockLexicalContext;
 import jdk.nashorn.internal.ir.BlockStatement;
 import jdk.nashorn.internal.ir.BreakNode;
 import jdk.nashorn.internal.ir.BreakableNode;
 import jdk.nashorn.internal.ir.CallNode;
 import jdk.nashorn.internal.ir.CaseNode;
 import jdk.nashorn.internal.ir.CatchNode;
 import jdk.nashorn.internal.ir.ContinueNode;
 import jdk.nashorn.internal.ir.EmptyNode;
 import jdk.nashorn.internal.ir.Expression;
 import jdk.nashorn.internal.ir.ExpressionStatement;
 import jdk.nashorn.internal.ir.ForNode;
 import jdk.nashorn.internal.ir.FunctionNode;
 import jdk.nashorn.internal.ir.FunctionNode.CompilationState;
 import jdk.nashorn.internal.ir.IdentNode;
 import jdk.nashorn.internal.ir.IfNode;
 import jdk.nashorn.internal.ir.IndexNode;
 import jdk.nashorn.internal.ir.JoinPredecessorExpression;
 import jdk.nashorn.internal.ir.LabelNode;
 import jdk.nashorn.internal.ir.LexicalContext;
 import jdk.nashorn.internal.ir.LiteralNode;
 import jdk.nashorn.internal.ir.LoopNode;
 import jdk.nashorn.internal.ir.Node;
 import jdk.nashorn.internal.ir.ObjectNode;
 import jdk.nashorn.internal.ir.PropertyKey;
 import jdk.nashorn.internal.ir.PropertyNode;
 import jdk.nashorn.internal.ir.ReturnNode;
 import jdk.nashorn.internal.ir.RuntimeNode;
 import jdk.nashorn.internal.ir.Statement;
 import jdk.nashorn.internal.ir.SwitchNode;
 import jdk.nashorn.internal.ir.TernaryNode;
 import jdk.nashorn.internal.ir.ThrowNode;
 import jdk.nashorn.internal.ir.TryNode;
 import jdk.nashorn.internal.ir.UnaryNode;
 import jdk.nashorn.internal.ir.VarNode;
 import jdk.nashorn.internal.ir.WhileNode;
 import jdk.nashorn.internal.ir.WithNode;
 import jdk.nashorn.internal.ir.debug.ASTWriter;
 import jdk.nashorn.internal.ir.debug.PrintVisitor;
 import jdk.nashorn.internal.runtime.Context;
 import jdk.nashorn.internal.runtime.ErrorManager;
 import jdk.nashorn.internal.runtime.JSErrorType;
 import jdk.nashorn.internal.runtime.ParserException;
 import jdk.nashorn.internal.runtime.RecompilableScriptFunctionData;
 import jdk.nashorn.internal.runtime.ScriptEnvironment;
 import jdk.nashorn.internal.runtime.ScriptingFunctions;
 import jdk.nashorn.internal.runtime.Source;
 import jdk.nashorn.internal.runtime.logging.DebugLogger;
 import jdk.nashorn.internal.runtime.logging.Loggable;
 import jdk.nashorn.internal.runtime.logging.Logger;
 /**
  * Builds the IR.
  */
 @Logger(name="parser")
 public class Parser extends AbstractParser implements Loggable {
     private static final String ARGUMENTS_NAME = CompilerConstants.ARGUMENTS_VAR.symbolName();
     /** Current env. */
     private final ScriptEnvironment env;
     /** Is scripting mode. */
     private final boolean scripting;
     private List<Statement> functionDeclarations;
     private final BlockLexicalContext lc = new BlockLexicalContext();
     private final Deque<Object> defaultNames = new ArrayDeque<>();
     /** Namespace for function names where not explicitly given */
     private final Namespace namespace;
     private final DebugLogger log;
     /** to receive line information from Lexer when scanning multine literals. */
     protected final Lexer.LineInfoReceiver lineInfoReceiver;
     private int nextFunctionId;
     /**
      * Constructor
      *
      * @param env     script environment
      * @param source  source to parse
      * @param errors  error manager
      */
     public Parser(final ScriptEnvironment env, final Source source, final ErrorManager errors) {
         this(env, source, errors, env._strict, null);
     }
     /**
      * Constructor
      *
      * @param env     script environment
      * @param source  source to parse
      * @param errors  error manager
      * @param strict  strict
      * @param log debug logger if one is needed
      */
     public Parser(final ScriptEnvironment env, final Source source, final ErrorManager errors, final boolean strict, final DebugLogger log) {
         this(env, source, errors, strict, FunctionNode.FIRST_FUNCTION_ID, 0, log);
     }
     /**
      * Construct a parser.
      *
      * @param env     script environment
      * @param source  source to parse
      * @param errors  error manager
      * @param strict  parser created with strict mode enabled.
      * @param nextFunctionId  starting value for assigning new unique ids to function nodes
      * @param lineOffset line offset to start counting lines from
      * @param log debug logger if one is needed
      */
     public Parser(final ScriptEnvironment env, final Source source, final ErrorManager errors, final boolean strict, final int nextFunctionId, final int lineOffset, final DebugLogger log) {
         super(source, errors, strict, lineOffset);
         this.env = env;
         this.namespace = new Namespace(env.getNamespace());
         this.nextFunctionId    = nextFunctionId;
         this.scripting = env._scripting;
         if (this.scripting) {
             this.lineInfoReceiver = new Lexer.LineInfoReceiver() {
                 @Override
                 public void lineInfo(final int receiverLine, final int receiverLinePosition) {
                     // update the parser maintained line information
                     Parser.this.line = receiverLine;
                     Parser.this.linePosition = receiverLinePosition;
                 }
             };
         } else {
             // non-scripting mode script can't have multi-line literals
             this.lineInfoReceiver = null;
         }
         this.log = log == null ? DebugLogger.DISABLED_LOGGER : log;
     }
     @Override
     public DebugLogger getLogger() {
         return log;
     }
     @Override
     public DebugLogger initLogger(final Context context) {
         return context.getLogger(this.getClass());
     }
     /**
      * Sets the name for the first function. This is only used when reparsing anonymous functions to ensure they can
      * preserve their already assigned name, as that name doesn't appear in their source text.
      * @param name the name for the first parsed function.
      */
     public void setFunctionName(final String name) {
         defaultNames.push(createIdentNode(0, 0, name));
     }
     /**
      * Execute parse and return the resulting function node.
      * Errors will be thrown and the error manager will contain information
      * if parsing should fail
      *
      * This is the default parse call, which will name the function node
      * {code :program} {@link CompilerConstants#PROGRAM}
      *
      * @return function node resulting from successful parse
      */
     public FunctionNode parse() {
         return parse(PROGRAM.symbolName(), 0, source.getLength(), false);
     }
     /**
      * Execute parse and return the resulting function node.
      * Errors will be thrown and the error manager will contain information
      * if parsing should fail
      *
      * This should be used to create one and only one function node
      *
      * @param scriptName name for the script, given to the parsed FunctionNode
      * @param startPos start position in source
      * @param len length of parse
      * @param allowPropertyFunction if true, "get" and "set" are allowed as first tokens of the program, followed by
      * a property getter or setter function. This is used when reparsing a function that can potentially be defined as a
      * property getter or setter in an object literal.
      *
      * @return function node resulting from successful parse
      */
     public FunctionNode parse(final String scriptName, final int startPos, final int len, final boolean allowPropertyFunction) {
         final boolean isTimingEnabled = env.isTimingEnabled();
         final long t0 = isTimingEnabled ? System.currentTimeMillis() : 0L;
         log.info(this, " begin for '", scriptName, "'");
         try {
             stream = new TokenStream();
             lexer  = new Lexer(source, startPos, len, stream, scripting && !env._no_syntax_extensions);
             lexer.line = lexer.pendingLine = lineOffset + 1;
             line = lineOffset;
             // Set up first token (skips opening EOL.)
             k = -1;
             next();
             // Begin parse.
             return program(scriptName, allowPropertyFunction);
         } catch (final Exception e) {
             handleParseException(e);
             return null;
         } finally {
             final String end = this + " end '" + scriptName + "'";
             if (isTimingEnabled) {
                 env._timing.accumulateTime(toString(), System.currentTimeMillis() - t0);
                 log.info(end, "' in ", System.currentTimeMillis() - t0, " ms");
             } else {
                 log.info(end);
             }
         }
     }
     /**
      * Parse and return the list of function parameter list. A comma
      * separated list of function parameter identifiers is expected to be parsed.
      * Errors will be thrown and the error manager will contain information
      * if parsing should fail. This method is used to check if parameter Strings
      * passed to "Function" constructor is a valid or not.
      *
      * @return the list of IdentNodes representing the formal parameter list
      */
     public List<IdentNode> parseFormalParameterList() {
         try {
             stream = new TokenStream();
             lexer  = new Lexer(source, stream, scripting && !env._no_syntax_extensions);
             // Set up first token (skips opening EOL.)
             k = -1;
             next();
             return formalParameterList(TokenType.EOF);
         } catch (final Exception e) {
             handleParseException(e);
             return null;
         }
     }
     /**
      * Execute parse and return the resulting function node.
      * Errors will be thrown and the error manager will contain information
      * if parsing should fail. This method is used to check if code String
      * passed to "Function" constructor is a valid function body or not.
      *
      * @return function node resulting from successful parse
      */
     public FunctionNode parseFunctionBody() {
         try {
             stream = new TokenStream();
             lexer  = new Lexer(source, stream, scripting && !env._no_syntax_extensions);
             final int functionLine = line;
             // Set up first token (skips opening EOL.)
             k = -1;
             next();
             // Make a fake token for the function.
             final long functionToken = Token.toDesc(FUNCTION, 0, source.getLength());
             // Set up the function to append elements.
             FunctionNode function = newFunctionNode(
                 functionToken,
                 new IdentNode(functionToken, Token.descPosition(functionToken), PROGRAM.symbolName()),
                 new ArrayList<IdentNode>(),
                 FunctionNode.Kind.NORMAL,
                 functionLine);
             functionDeclarations = new ArrayList<>();
             sourceElements(false);
             addFunctionDeclarations(function);
             functionDeclarations = null;
             expect(EOF);
             function.setFinish(source.getLength() - 1);
             function = restoreFunctionNode(function, token); //commit code
             function = function.setBody(lc, function.getBody().setNeedsScope(lc));
             printAST(function);
             return function;
         } catch (final Exception e) {
             handleParseException(e);
             return null;
         }
     }
     private void handleParseException(final Exception e) {
         // Extract message from exception.  The message will be in error
         // message format.
         String message = e.getMessage();
         // If empty message.
         if (message == null) {
             message = e.toString();
         }
         // Issue message.
         if (e instanceof ParserException) {
             errors.error((ParserException)e);
         } else {
             errors.error(message);
         }
         if (env._dump_on_error) {
             e.printStackTrace(env.getErr());
         }
     }
     /**
      * Skip to a good parsing recovery point.
      */
     private void recover(final Exception e) {
         if (e != null) {
             // Extract message from exception.  The message will be in error
             // message format.
             String message = e.getMessage();
             // If empty message.
             if (message == null) {
                 message = e.toString();
             }
             // Issue message.
             if (e instanceof ParserException) {
                 errors.error((ParserException)e);
             } else {
                 errors.error(message);
             }
             if (env._dump_on_error) {
                 e.printStackTrace(env.getErr());
             }
         }
         // Skip to a recovery point.
 loop:
         while (true) {
             switch (type) {
             case EOF:
                 // Can not go any further.
                 break loop;
             case EOL:
             case SEMICOLON:
             case RBRACE:
                 // Good recovery points.
                 next();
                 break loop;
             default:
                 // So we can recover after EOL.
                 nextOrEOL();
                 break;
             }
         }
     }
     /**
      * Set up a new block.
      *
      * @return New block.
      */
     private Block newBlock() {
         return lc.push(new Block(token, Token.descPosition(token)));
     }
     /**
      * Set up a new function block.
      *
      * @param ident Name of function.
      * @return New block.
      */
     private FunctionNode newFunctionNode(final long startToken, final IdentNode ident, final List<IdentNode> parameters, final FunctionNode.Kind kind, final int functionLine) {
         // Build function name.
         final StringBuilder sb = new StringBuilder();
         final FunctionNode parentFunction = lc.getCurrentFunction();
         if (parentFunction != null && !parentFunction.isProgram()) {
             sb.append(parentFunction.getName()).append('$');
         }
         assert ident.getName() != null;
         sb.append(ident.getName());
         final String name = namespace.uniqueName(sb.toString());
         assert parentFunction != null || name.equals(PROGRAM.symbolName()) || name.startsWith(RecompilableScriptFunctionData.RECOMPILATION_PREFIX) : "name = " + name;
         int flags = 0;
         if (isStrictMode) {
             flags |= FunctionNode.IS_STRICT;
         }
         if (parentFunction == null) {
             flags |= FunctionNode.IS_PROGRAM;
         }
         // Start new block.
         final FunctionNode functionNode =
             new FunctionNode(
                 source,
                 nextFunctionId++,
                 functionLine,
                 token,
                 Token.descPosition(token),
                 startToken,
                 namespace,
                 ident,
                 name,
                 parameters,
                 kind,
                 flags);
         lc.push(functionNode);
         // Create new block, and just put it on the context stack, restoreFunctionNode() will associate it with the
         // FunctionNode.
         newBlock();
         return functionNode;
     }
     /**
      * Restore the current block.
      */
     private Block restoreBlock(final Block block) {
         return lc.pop(block);
     }
     private FunctionNode restoreFunctionNode(final FunctionNode functionNode, final long lastToken) {
         final Block newBody = restoreBlock(lc.getFunctionBody(functionNode));
         return lc.pop(functionNode).
             setBody(lc, newBody).
             setLastToken(lc, lastToken).
             setState(lc, errors.hasErrors() ? CompilationState.PARSE_ERROR : CompilationState.PARSED);
     }
     /**
      * Get the statements in a block.
      * @return Block statements.
      */
     private Block getBlock(final boolean needsBraces) {
         // Set up new block. Captures LBRACE.
         Block newBlock = newBlock();
         try {
             // Block opening brace.
             if (needsBraces) {
                 expect(LBRACE);
             }
             // Accumulate block statements.
             statementList();
         } finally {
             newBlock = restoreBlock(newBlock);
         }
         final int possibleEnd = Token.descPosition(token) + Token.descLength(token);
         // Block closing brace.
         if (needsBraces) {
             expect(RBRACE);
         }
         newBlock.setFinish(possibleEnd);
         return newBlock;
     }
     /**
      * Get all the statements generated by a single statement.
      * @return Statements.
      */
     private Block getStatement() {
         if (type == LBRACE) {
             return getBlock(true);
         }
         // Set up new block. Captures first token.
         Block newBlock = newBlock();
         try {
             statement();
         } finally {
             newBlock = restoreBlock(newBlock);
         }
         return newBlock;
     }
     /**
      * Detect calls to special functions.
      * @param ident Called function.
      */
     private void detectSpecialFunction(final IdentNode ident) {
         final String name = ident.getName();
         if (EVAL.symbolName().equals(name)) {
             markEval(lc);
         }
     }
     /**
      * Detect use of special properties.
      * @param ident Referenced property.
      */
     private void detectSpecialProperty(final IdentNode ident) {
         if (isArguments(ident)) {
             lc.setFlag(lc.getCurrentFunction(), FunctionNode.USES_ARGUMENTS);
         }
     }
     private static boolean isArguments(final String name) {
         return ARGUMENTS_NAME.equals(name);
     }
     private static boolean isArguments(final IdentNode ident) {
         return isArguments(ident.getName());
     }
     /**
      * Tells whether a IdentNode can be used as L-value of an assignment
      *
      * @param ident IdentNode to be checked
      * @return whether the ident can be used as L-value
      */
     private static boolean checkIdentLValue(final IdentNode ident) {
         return Token.descType(ident.getToken()).getKind() != TokenKind.KEYWORD;
     }
     /**
      * Verify an assignment expression.
      * @param op  Operation token.
      * @param lhs Left hand side expression.
      * @param rhs Right hand side expression.
      * @return Verified expression.
      */
     private Expression verifyAssignment(final long op, final Expression lhs, final Expression rhs) {
         final TokenType opType = Token.descType(op);
         switch (opType) {
         case ASSIGN:
         case ASSIGN_ADD:
         case ASSIGN_BIT_AND:
         case ASSIGN_BIT_OR:
         case ASSIGN_BIT_XOR:
         case ASSIGN_DIV:
         case ASSIGN_MOD:
         case ASSIGN_MUL:
         case ASSIGN_SAR:
         case ASSIGN_SHL:
         case ASSIGN_SHR:
         case ASSIGN_SUB:
             if (!(lhs instanceof AccessNode ||
                   lhs instanceof IndexNode ||
                   lhs instanceof IdentNode)) {
                 return referenceError(lhs, rhs, env._early_lvalue_error);
             }
             if (lhs instanceof IdentNode) {
                 if (!checkIdentLValue((IdentNode)lhs)) {
                     return referenceError(lhs, rhs, false);
                 }
                 verifyStrictIdent((IdentNode)lhs, "assignment");
             }
             break;
         default:
             break;
         }
         // Build up node.
         if(BinaryNode.isLogical(opType)) {
             return new BinaryNode(op, new JoinPredecessorExpression(lhs), new JoinPredecessorExpression(rhs));
         }
         return new BinaryNode(op, lhs, rhs);
     }
     /**
      * Reduce increment/decrement to simpler operations.
      * @param firstToken First token.
      * @param tokenType  Operation token (INCPREFIX/DEC.)
      * @param expression Left hand side expression.
      * @param isPostfix  Prefix or postfix.
      * @return           Reduced expression.
      */
     private static UnaryNode incDecExpression(final long firstToken, final TokenType tokenType, final Expression expression, final boolean isPostfix) {
         if (isPostfix) {
             return new UnaryNode(Token.recast(firstToken, tokenType == DECPREFIX ? DECPOSTFIX : INCPOSTFIX), expression.getStart(), Token.descPosition(firstToken) + Token.descLength(firstToken), expression);
         }
         return new UnaryNode(firstToken, expression);
     }
     /**
      * -----------------------------------------------------------------------
      *
      * Grammar based on
      *
      *      ECMAScript Language Specification
      *      ECMA-262 5th Edition / December 2009
      *
      * -----------------------------------------------------------------------
      */
     /**
      * Program :
      *      SourceElements?
      *
      * See 14
      *
      * Parse the top level script.
      */
     private FunctionNode program(final String scriptName, final boolean allowPropertyFunction) {
         // Make a pseudo-token for the script holding its start and length.
         final long functionToken = Token.toDesc(FUNCTION, Token.descPosition(Token.withDelimiter(token)), source.getLength());
         final int  functionLine  = line;
         // Set up the script to append elements.
         FunctionNode script = newFunctionNode(
             functionToken,
             new IdentNode(functionToken, Token.descPosition(functionToken), scriptName),
             new ArrayList<IdentNode>(),
             FunctionNode.Kind.SCRIPT,
             functionLine);
         functionDeclarations = new ArrayList<>();
         sourceElements(allowPropertyFunction);
         addFunctionDeclarations(script);
         functionDeclarations = null;
         expect(EOF);
         script.setFinish(source.getLength() - 1);
         script = restoreFunctionNode(script, token); //commit code
         script = script.setBody(lc, script.getBody().setNeedsScope(lc));
         return script;
     }
     /**
      * Directive value or null if statement is not a directive.
      *
      * @param stmt Statement to be checked
      * @return Directive value if the given statement is a directive
      */
     private String getDirective(final Node stmt) {
         if (stmt instanceof ExpressionStatement) {
             final Node expr = ((ExpressionStatement)stmt).getExpression();
             if (expr instanceof LiteralNode) {
                 final LiteralNode<?> lit = (LiteralNode<?>)expr;
                 final long litToken = lit.getToken();
                 final TokenType tt = Token.descType(litToken);
                 // A directive is either a string or an escape string
                 if (tt == TokenType.STRING || tt == TokenType.ESCSTRING) {
                     // Make sure that we don't unescape anything. Return as seen in source!
                     return source.getString(lit.getStart(), Token.descLength(litToken));
                 }
             }
         }
         return null;
     }
     /**
      * SourceElements :
      *      SourceElement
      *      SourceElements SourceElement
      *
      * See 14
      *
      * Parse the elements of the script or function.
      */
     private void sourceElements(final boolean shouldAllowPropertyFunction) {
         List<Node>    directiveStmts        = null;
         boolean       checkDirective        = true;
         boolean       allowPropertyFunction = shouldAllowPropertyFunction;
         final boolean oldStrictMode         = isStrictMode;
         try {
             // If is a script, then process until the end of the script.
             while (type != EOF) {
                 // Break if the end of a code block.
                 if (type == RBRACE) {
                     break;
                 }
                 try {
                     // Get the next element.
                     statement(true, allowPropertyFunction);
                     allowPropertyFunction = false;
                     // check for directive prologues
                     if (checkDirective) {
                         // skip any debug statement like line number to get actual first line
                         final Node lastStatement = lc.getLastStatement();
                         // get directive prologue, if any
                         final String directive = getDirective(lastStatement);
                         // If we have seen first non-directive statement,
                         // no more directive statements!!
                         checkDirective = directive != null;
                         if (checkDirective) {
                             if (!oldStrictMode) {
                                 if (directiveStmts == null) {
                                     directiveStmts = new ArrayList<>();
                                 }
                                 directiveStmts.add(lastStatement);
                             }
                             // handle use strict directive
                             if ("use strict".equals(directive)) {
                                 isStrictMode = true;
                                 final FunctionNode function = lc.getCurrentFunction();
                                 lc.setFlag(lc.getCurrentFunction(), FunctionNode.IS_STRICT);
                                 // We don't need to check these, if lexical environment is already strict
                                 if (!oldStrictMode && directiveStmts != null) {
                                     // check that directives preceding this one do not violate strictness
                                     for (final Node statement : directiveStmts) {
                                         // the get value will force unescape of preceeding
                                         // escaped string directives
                                         getValue(statement.getToken());
                                     }
                                     // verify that function name as well as parameter names
                                     // satisfy strict mode restrictions.
                                     verifyStrictIdent(function.getIdent(), "function name");
                                     for (final IdentNode param : function.getParameters()) {
                                         verifyStrictIdent(param, "function parameter");
                                     }
                                 }
                             } else if (Context.DEBUG) {
                                 final int flag = FunctionNode.getDirectiveFlag(directive);
                                 if (flag != 0) {
                                     final FunctionNode function = lc.getCurrentFunction();
                                     lc.setFlag(function, flag);
                                 }
                             }
                         }
                     }
                 } catch (final Exception e) {
                     //recover parsing
                     recover(e);
                 }
                 // No backtracking from here on.
                 stream.commit(k);
             }
         } finally {
             isStrictMode = oldStrictMode;
         }
     }
     /**
      * Statement :
      *      Block
      *      VariableStatement
      *      EmptyStatement
      *      ExpressionStatement
      *      IfStatement
      *      IterationStatement
      *      ContinueStatement
      *      BreakStatement
      *      ReturnStatement
      *      WithStatement
      *      LabelledStatement
      *      SwitchStatement
      *      ThrowStatement
      *      TryStatement
      *      DebuggerStatement
      *
      * see 12
      *
      * Parse any of the basic statement types.
      */
     private void statement() {
         statement(false, false);
     }
     /**
      * @param topLevel does this statement occur at the "top level" of a script or a function?
      */
     private void statement(final boolean topLevel, final boolean allowPropertyFunction) {
         if (type == FUNCTION) {
             // As per spec (ECMA section 12), function declarations as arbitrary statement
             // is not "portable". Implementation can issue a warning or disallow the same.
             functionExpression(true, topLevel);
             return;
         }
         switch (type) {
         case LBRACE:
             block();
             break;
         case VAR:
             variableStatement(true);
             break;
         case SEMICOLON:
             emptyStatement();
             break;
         case IF:
             ifStatement();
             break;
         case FOR:
             forStatement();
             break;
         case WHILE:
             whileStatement();
             break;
         case DO:
             doStatement();
             break;
         case CONTINUE:
             continueStatement();
             break;
         case BREAK:
             breakStatement();
             break;
         case RETURN:
             returnStatement();
             break;
         case YIELD:
             yieldStatement();
             break;
         case WITH:
             withStatement();
             break;
         case SWITCH:
             switchStatement();
             break;
         case THROW:
             throwStatement();
             break;
         case TRY:
             tryStatement();
             break;
         case DEBUGGER:
             debuggerStatement();
             break;
         case RPAREN:
         case RBRACKET:
         case EOF:
             expect(SEMICOLON);
             break;
         default:
             if (env._const_as_var && type == CONST) {
                 variableStatement(true);
                 break;
             }
             if (type == IDENT || isNonStrictModeIdent()) {
                 if (T(k + 1) == COLON) {
                     labelStatement();
                     return;
                 }
                 if(allowPropertyFunction) {
                     final String ident = (String)getValue();
                     final long propertyToken = token;
                     final int propertyLine = line;
                     if("get".equals(ident)) {
                         next();
                         addPropertyFunctionStatement(propertyGetterFunction(propertyToken, propertyLine));
                         return;
                     } else if("set".equals(ident)) {
                         next();
                         addPropertyFunctionStatement(propertySetterFunction(propertyToken, propertyLine));
                         return;
                     }
                 }
             }
             expressionStatement();
             break;
         }
     }
     private void addPropertyFunctionStatement(final PropertyFunction propertyFunction) {
         final FunctionNode fn = propertyFunction.functionNode;
         functionDeclarations.add(new ExpressionStatement(fn.getLineNumber(), fn.getToken(), finish, fn));
     }
     /**
      * block :
      *      { StatementList? }
      *
      * see 12.1
      *
      * Parse a statement block.
      */
     private void block() {
         appendStatement(new BlockStatement(line, getBlock(true)));
     }
     /**
      * StatementList :
      *      Statement
      *      StatementList Statement
      *
      * See 12.1
      *
      * Parse a list of statements.
      */
     private void statementList() {
         // Accumulate statements until end of list. */
 loop:
         while (type != EOF) {
             switch (type) {
             case EOF:
             case CASE:
             case DEFAULT:
             case RBRACE:
                 break loop;
             default:
                 break;
             }
             // Get next statement.
             statement();
         }
     }
     /**
      * Make sure that in strict mode, the identifier name used is allowed.
      *
      * @param ident         Identifier that is verified
      * @param contextString String used in error message to give context to the user
      */
     private void verifyStrictIdent(final IdentNode ident, final String contextString) {
         if (isStrictMode) {
             switch (ident.getName()) {
             case "eval":
             case "arguments":
                 throw error(AbstractParser.message("strict.name", ident.getName(), contextString), ident.getToken());
             default:
                 break;
             }
             if (ident.isFutureStrictName()) {
                 throw error(AbstractParser.message("strict.name", ident.getName(), contextString), ident.getToken());
             }
         }
     }
     /**
      * VariableStatement :
      *      var VariableDeclarationList ;
      *
      * VariableDeclarationList :
      *      VariableDeclaration
      *      VariableDeclarationList , VariableDeclaration
      *
      * VariableDeclaration :
      *      Identifier Initializer?
      *
      * Initializer :
      *      = AssignmentExpression
      *
      * See 12.2
      *
      * Parse a VAR statement.
      * @param isStatement True if a statement (not used in a FOR.)
      */
     private List<VarNode> variableStatement(final boolean isStatement) {
         // VAR tested in caller.
         next();
         final List<VarNode> vars = new ArrayList<>();
         while (true) {
             // Get starting token.
             final int  varLine  = line;
             final long varToken = token;
             // Get name of var.
             final IdentNode name = getIdent();
             verifyStrictIdent(name, "variable name");
             // Assume no init.
             Expression init = null;
             // Look for initializer assignment.
             if (type == ASSIGN) {
                 next();
                 // Get initializer expression. Suppress IN if not statement.
                 defaultNames.push(name);
                 try {
                     init = assignmentExpression(!isStatement);
                 } finally {
                     defaultNames.pop();
                 }
             }
             // Allocate var node.
             final VarNode var = new VarNode(varLine, varToken, finish, name, init);
             vars.add(var);
             appendStatement(var);
             if (type != COMMARIGHT) {
                 break;
             }
             next();
         }
         // If is a statement then handle end of line.
         if (isStatement) {
             final boolean semicolon = type == SEMICOLON;
             endOfLine();
             if (semicolon) {
                 lc.getCurrentBlock().setFinish(finish);
             }
         }
         return vars;
     }
     /**
      * EmptyStatement :
      *      ;
      *
      * See 12.3
      *
      * Parse an empty statement.
      */
     private void emptyStatement() {
         if (env._empty_statements) {
             appendStatement(new EmptyNode(line, token, Token.descPosition(token) + Token.descLength(token)));
         }
         // SEMICOLON checked in caller.
         next();
     }
     /**
      * ExpressionStatement :
      *      Expression ; // [lookahead ~( or  function )]
      *
      * See 12.4
      *
      * Parse an expression used in a statement block.
      */
     private void expressionStatement() {
         // Lookahead checked in caller.
         final int  expressionLine  = line;
         final long expressionToken = token;
         // Get expression and add as statement.
         final Expression expression = expression();
         ExpressionStatement expressionStatement = null;
         if (expression != null) {
             expressionStatement = new ExpressionStatement(expressionLine, expressionToken, finish, expression);
             appendStatement(expressionStatement);
         } else {
             expect(null);
         }
         endOfLine();
         if (expressionStatement != null) {
             expressionStatement.setFinish(finish);
             lc.getCurrentBlock().setFinish(finish);
         }
     }
     /**
      * IfStatement :
      *      if ( Expression ) Statement else Statement
      *      if ( Expression ) Statement
      *
      * See 12.5
      *
      * Parse an IF statement.
      */
     private void ifStatement() {
         // Capture IF token.
         final int  ifLine  = line;
         final long ifToken = token;
          // IF tested in caller.
         next();
         expect(LPAREN);
         final Expression test = expression();
         expect(RPAREN);
         final Block pass = getStatement();
         Block fail = null;
         if (type == ELSE) {
             next();
             fail = getStatement();
         }
         appendStatement(new IfNode(ifLine, ifToken, fail != null ? fail.getFinish() : pass.getFinish(), test, pass, fail));
     }
     /**
      * ... IterationStatement:
      *           ...
      *           for ( Expression[NoIn]?; Expression? ; Expression? ) Statement
      *           for ( var VariableDeclarationList[NoIn]; Expression? ; Expression? ) Statement
      *           for ( LeftHandSideExpression in Expression ) Statement
      *           for ( var VariableDeclaration[NoIn] in Expression ) Statement
      *
      * See 12.6
      *
      * Parse a FOR statement.
      */
     private void forStatement() {
         // Create FOR node, capturing FOR token.
         ForNode forNode = new ForNode(line, token, Token.descPosition(token), null, ForNode.IS_FOR);
         lc.push(forNode);
         try {
             // FOR tested in caller.
             next();
             // Nashorn extension: for each expression.
             // iterate property values rather than property names.
             if (!env._no_syntax_extensions && type == IDENT && "each".equals(getValue())) {
                 forNode = forNode.setIsForEach(lc);
                 next();
             }
             expect(LPAREN);
             List<VarNode> vars = null;
             switch (type) {
             case VAR:
                 // Var statements captured in for outer block.
                 vars = variableStatement(false);
                 break;
             case SEMICOLON:
                 break;
             default:
                 if (env._const_as_var && type == CONST) {
                     // Var statements captured in for outer block.
                     vars = variableStatement(false);
                     break;
                 }
                 final Expression expression = expression(unaryExpression(), COMMARIGHT.getPrecedence(), true);
                 forNode = forNode.setInit(lc, expression);
                 break;
             }
             switch (type) {
             case SEMICOLON:
                 // for (init; test; modify)
                 // for each (init; test; modify) is invalid
                 if (forNode.isForEach()) {
                     throw error(AbstractParser.message("for.each.without.in"), token);
                 }
                 expect(SEMICOLON);
                 if (type != SEMICOLON) {
                     forNode = forNode.setTest(lc, joinPredecessorExpression());
                 }
                 expect(SEMICOLON);
                 if (type != RPAREN) {
                     forNode = forNode.setModify(lc, joinPredecessorExpression());
                 }
                 break;
             case IN:
                 forNode = forNode.setIsForIn(lc).setTest(lc, new JoinPredecessorExpression());
                 if (vars != null) {
                     // for (var i in obj)
                     if (vars.size() == 1) {
                         forNode = forNode.setInit(lc, new IdentNode(vars.get(0).getName()));
                     } else {
                         // for (var i, j in obj) is invalid
                         throw error(AbstractParser.message("many.vars.in.for.in.loop"), vars.get(1).getToken());
                     }
                 } else {
                     // for (expr in obj)
                     final Node init = forNode.getInit();
                     assert init != null : "for..in init expression can not be null here";
                     // check if initial expression is a valid L-value
                     if (!(init instanceof AccessNode ||
                           init instanceof IndexNode ||
                           init instanceof IdentNode)) {
                         throw error(AbstractParser.message("not.lvalue.for.in.loop"), init.getToken());
                     }
                     if (init instanceof IdentNode) {
                         if (!checkIdentLValue((IdentNode)init)) {
                             throw error(AbstractParser.message("not.lvalue.for.in.loop"), init.getToken());
                         }
                         verifyStrictIdent((IdentNode)init, "for-in iterator");
                     }
                 }
                 next();
                 // Get the collection expression.
                 forNode = forNode.setModify(lc, joinPredecessorExpression());
                 break;
             default:
                 expect(SEMICOLON);
                 break;
             }
             expect(RPAREN);
             // Set the for body.
             final Block body = getStatement();
             forNode = forNode.setBody(lc, body);
             forNode.setFinish(body.getFinish());
             appendStatement(forNode);
         } finally {
             lc.pop(forNode);
         }
      }
     /**
      * ... IterationStatement :
      *           ...
      *           Expression[NoIn]?; Expression? ; Expression?
      *           var VariableDeclarationList[NoIn]; Expression? ; Expression?
      *           LeftHandSideExpression in Expression
      *           var VariableDeclaration[NoIn] in Expression
      *
      * See 12.6
      *
      * Parse the control section of a FOR statement.  Also used for
      * comprehensions.
      * @param forNode Owning FOR.
      */
     /**
      * ...IterationStatement :
      *           ...
      *           while ( Expression ) Statement
      *           ...
      *
      * See 12.6
      *
      * Parse while statement.
      */
     private void whileStatement() {
         // Capture WHILE token.
         final long whileToken = token;
         // WHILE tested in caller.
         next();
         // Construct WHILE node.
         WhileNode whileNode = new WhileNode(line, whileToken, Token.descPosition(whileToken), false);
         lc.push(whileNode);
         try {
             expect(LPAREN);
             final int whileLine = line;
             final JoinPredecessorExpression test = joinPredecessorExpression();
             expect(RPAREN);
             final Block body = getStatement();
             appendStatement(whileNode =
                 new WhileNode(whileLine, whileToken, finish, false).
                     setTest(lc, test).
                     setBody(lc, body));
         } finally {
             lc.pop(whileNode);
         }
     }
     /**
      * ...IterationStatement :
      *           ...
      *           do Statement while( Expression ) ;
      *           ...
      *
      * See 12.6
      *
      * Parse DO WHILE statement.
      */
     private void doStatement() {
         // Capture DO token.
         final long doToken = token;
         // DO tested in the caller.
         next();
         WhileNode doWhileNode = new WhileNode(-1, doToken, Token.descPosition(doToken), true);
         lc.push(doWhileNode);
         try {
            // Get DO body.
             final Block body = getStatement();
             expect(WHILE);
             expect(LPAREN);
             final int doLine = line;
             final JoinPredecessorExpression test = joinPredecessorExpression();
             expect(RPAREN);
             if (type == SEMICOLON) {
                 endOfLine();
             }
             doWhileNode.setFinish(finish);
             //line number is last
             appendStatement(doWhileNode =
                 new WhileNode(doLine, doToken, finish, true).
                     setBody(lc, body).
                     setTest(lc, test));
         } finally {
             lc.pop(doWhileNode);
         }
     }
     /**
      * ContinueStatement :
      *      continue Identifier? ; // [no LineTerminator here]
      *
      * See 12.7
      *
      * Parse CONTINUE statement.
      */
     private void continueStatement() {
         // Capture CONTINUE token.
         final int  continueLine  = line;
         final long continueToken = token;
         // CONTINUE tested in caller.
         nextOrEOL();
         LabelNode labelNode = null;
         // SEMICOLON or label.
         switch (type) {
         case RBRACE:
         case SEMICOLON:
         case EOL:
         case EOF:
             break;
         default:
             final IdentNode ident = getIdent();
             labelNode = lc.findLabel(ident.getName());
             if (labelNode == null) {
                 throw error(AbstractParser.message("undefined.label", ident.getName()), ident.getToken());
             }
             break;
         }
         final String labelName = labelNode == null ? null : labelNode.getLabelName();
         final LoopNode targetNode = lc.getContinueTo(labelName);
         if (targetNode == null) {
             throw error(AbstractParser.message("illegal.continue.stmt"), continueToken);
         }
         endOfLine();
         // Construct and add CONTINUE node.
         appendStatement(new ContinueNode(continueLine, continueToken, finish, labelName));
     }
     /**
      * BreakStatement :
      *      break Identifier? ; // [no LineTerminator here]
      *
      * See 12.8
      *
      */
     private void breakStatement() {
         // Capture BREAK token.
         final int  breakLine  = line;
         final long breakToken = token;
         // BREAK tested in caller.
         nextOrEOL();
         LabelNode labelNode = null;
         // SEMICOLON or label.
         switch (type) {
         case RBRACE:
         case SEMICOLON:
         case EOL:
         case EOF:
             break;
         default:
             final IdentNode ident = getIdent();
             labelNode = lc.findLabel(ident.getName());
             if (labelNode == null) {
                 throw error(AbstractParser.message("undefined.label", ident.getName()), ident.getToken());
             }
             break;
         }
         //either an explicit label - then get its node or just a "break" - get first breakable
         //targetNode is what we are breaking out from.
         final String labelName = labelNode == null ? null : labelNode.getLabelName();
         final BreakableNode targetNode = lc.getBreakable(labelName);
         if (targetNode == null) {
             throw error(AbstractParser.message("illegal.break.stmt"), breakToken);
         }
         endOfLine();
         // Construct and add BREAK node.
         appendStatement(new BreakNode(breakLine, breakToken, finish, labelName));
     }
     /**
      * ReturnStatement :
      *      return Expression? ; // [no LineTerminator here]
      *
      * See 12.9
      *
      * Parse RETURN statement.
      */
     private void returnStatement() {
         // check for return outside function
         if (lc.getCurrentFunction().getKind() == FunctionNode.Kind.SCRIPT) {
             throw error(AbstractParser.message("invalid.return"));
         }
         // Capture RETURN token.
         final int  returnLine  = line;
         final long returnToken = token;
         // RETURN tested in caller.
         nextOrEOL();
         Expression expression = null;
         // SEMICOLON or expression.
         switch (type) {
         case RBRACE:
         case SEMICOLON:
         case EOL:
         case EOF:
             break;
         default:
             expression = expression();
             break;
         }
         endOfLine();
         // Construct and add RETURN node.
         appendStatement(new ReturnNode(returnLine, returnToken, finish, expression));
     }
     /**
      * YieldStatement :
      *      yield Expression? ; // [no LineTerminator here]
      *
      * JavaScript 1.8
      *
      * Parse YIELD statement.
      */
     private void yieldStatement() {
         // Capture YIELD token.
         final int  yieldLine  = line;
         final long yieldToken = token;
         // YIELD tested in caller.
         nextOrEOL();
         Expression expression = null;
         // SEMICOLON or expression.
         switch (type) {
         case RBRACE:
         case SEMICOLON:
         case EOL:
         case EOF:
             break;
         default:
             expression = expression();
             break;
         }
         endOfLine();
         // Construct and add YIELD node.
         appendStatement(new ReturnNode(yieldLine, yieldToken, finish, expression));
     }
     /**
      * WithStatement :
      *      with ( Expression ) Statement
      *
      * See 12.10
      *
      * Parse WITH statement.
      */
     private void withStatement() {
         // Capture WITH token.
         final int  withLine  = line;
         final long withToken = token;
         // WITH tested in caller.
         next();
         // ECMA 12.10.1 strict mode restrictions
         if (isStrictMode) {
             throw error(AbstractParser.message("strict.no.with"), withToken);
         }
         // Get WITH expression.
         WithNode withNode = new WithNode(withLine, withToken, finish);
         try {
             lc.push(withNode);
             expect(LPAREN);
             withNode = withNode.setExpression(lc, expression());
             expect(RPAREN);
             withNode = withNode.setBody(lc, getStatement());
         } finally {
             lc.pop(withNode);
         }
         appendStatement(withNode);
     }
     /**
      * SwitchStatement :
      *      switch ( Expression ) CaseBlock
      *
      * CaseBlock :
      *      { CaseClauses? }
      *      { CaseClauses? DefaultClause CaseClauses }
      *
      * CaseClauses :
      *      CaseClause
      *      CaseClauses CaseClause
      *
      * CaseClause :
      *      case Expression : StatementList?
      *
      * DefaultClause :
      *      default : StatementList?
      *
      * See 12.11
      *
      * Parse SWITCH statement.
      */
     private void switchStatement() {
         final int  switchLine  = line;
         final long switchToken = token;
         // SWITCH tested in caller.
         next();
         // Create and add switch statement.
         SwitchNode switchNode = new SwitchNode(switchLine, switchToken, Token.descPosition(switchToken), null, new ArrayList<CaseNode>(), null);
         lc.push(switchNode);
         try {
             expect(LPAREN);
             switchNode = switchNode.setExpression(lc, expression());
             expect(RPAREN);
             expect(LBRACE);
             // Prepare to accumulate cases.
             final List<CaseNode> cases = new ArrayList<>();
             CaseNode defaultCase = null;
             while (type != RBRACE) {
                 // Prepare for next case.
                 Expression caseExpression = null;
                 final long caseToken = token;
                 switch (type) {
                 case CASE:
                     next();
                     caseExpression = expression();
                     break;
                 case DEFAULT:
                     if (defaultCase != null) {
                         throw error(AbstractParser.message("duplicate.default.in.switch"));
                     }
                     next();
                     break;
                 default:
                     // Force an error.
                     expect(CASE);
                     break;
                 }
                 expect(COLON);
                 // Get CASE body.
                 final Block statements = getBlock(false);
                 final CaseNode caseNode = new CaseNode(caseToken, finish, caseExpression, statements);
                 statements.setFinish(finish);
                 if (caseExpression == null) {
                     defaultCase = caseNode;
                 }
                 cases.add(caseNode);
             }
             switchNode = switchNode.setCases(lc, cases, defaultCase);
             next();
             switchNode.setFinish(finish);
             appendStatement(switchNode);
         } finally {
             lc.pop(switchNode);
         }
     }
     /**
      * LabelledStatement :
      *      Identifier : Statement
      *
      * See 12.12
      *
      * Parse label statement.
      */
     private void labelStatement() {
         // Capture label token.
         final long labelToken = token;
         // Get label ident.
         final IdentNode ident = getIdent();
         expect(COLON);
         if (lc.findLabel(ident.getName()) != null) {
             throw error(AbstractParser.message("duplicate.label", ident.getName()), labelToken);
         }
         LabelNode labelNode = new LabelNode(line, labelToken, finish, ident.getName(), null);
         try {
             lc.push(labelNode);
             labelNode = labelNode.setBody(lc, getStatement());
             labelNode.setFinish(finish);
             appendStatement(labelNode);
         } finally {
             assert lc.peek() instanceof LabelNode;
             lc.pop(labelNode);
         }
     }
    /**
      * ThrowStatement :
      *      throw Expression ; // [no LineTerminator here]
      *
      * See 12.13
      *
      * Parse throw statement.
      */
     private void throwStatement() {
         // Capture THROW token.
         final int  throwLine  = line;
         final long throwToken = token;
         // THROW tested in caller.
         nextOrEOL();
         Expression expression = null;
         // SEMICOLON or expression.
         switch (type) {
         case RBRACE:
         case SEMICOLON:
         case EOL:
             break;
         default:
             expression = expression();
             break;
         }
         if (expression == null) {
             throw error(AbstractParser.message("expected.operand", type.getNameOrType()));
         }
         endOfLine();
         appendStatement(new ThrowNode(throwLine, throwToken, finish, expression, false));
     }
     /**
      * TryStatement :
      *      try Block Catch
      *      try Block Finally
      *      try Block Catch Finally
      *
      * Catch :
      *      catch( Identifier if Expression ) Block
      *      catch( Identifier ) Block
      *
      * Finally :
      *      finally Block
      *
      * See 12.14
      *
      * Parse TRY statement.
      */
     private void tryStatement() {
         // Capture TRY token.
         final int  tryLine  = line;
         final long tryToken = token;
         // TRY tested in caller.
         next();
         // Container block needed to act as target for labeled break statements
         final int startLine = line;
         Block outer = newBlock();
         // Create try.
         try {
             final Block       tryBody     = getBlock(true);
             final List<Block> catchBlocks = new ArrayList<>();
             while (type == CATCH) {
                 final int  catchLine  = line;
                 final long catchToken = token;
                 next();
                 expect(LPAREN);
                 final IdentNode exception = getIdent();
                 // ECMA 12.4.1 strict mode restrictions
                 verifyStrictIdent(exception, "catch argument");
                 // Nashorn extension: catch clause can have optional
                 // condition. So, a single try can have more than one
                 // catch clause each with it's own condition.
                 final Expression ifExpression;
                 if (!env._no_syntax_extensions && type == IF) {
                     next();
                     // Get the exception condition.
                     ifExpression = expression();
                 } else {
                     ifExpression = null;
                 }
                 expect(RPAREN);
                 Block catchBlock = newBlock();
                 try {
                     // Get CATCH body.
                     final Block catchBody = getBlock(true);
                     final CatchNode catchNode = new CatchNode(catchLine, catchToken, finish, exception, ifExpression, catchBody, false);
                     appendStatement(catchNode);
                 } finally {
                     catchBlock = restoreBlock(catchBlock);
                     catchBlocks.add(catchBlock);
                 }
                 // If unconditional catch then should to be the end.
                 if (ifExpression == null) {
                     break;
                 }
             }
             // Prepare to capture finally statement.
             Block finallyStatements = null;
             if (type == FINALLY) {
                 next();
                 finallyStatements = getBlock(true);
             }
             // Need at least one catch or a finally.
             if (catchBlocks.isEmpty() && finallyStatements == null) {
                 throw error(AbstractParser.message("missing.catch.or.finally"), tryToken);
             }
             final TryNode tryNode = new TryNode(tryLine, tryToken, Token.descPosition(tryToken), tryBody, catchBlocks, finallyStatements);
             // Add try.
             assert lc.peek() == outer;
             appendStatement(tryNode);
             tryNode.setFinish(finish);
             outer.setFinish(finish);
         } finally {
             outer = restoreBlock(outer);
         }
         appendStatement(new BlockStatement(startLine, outer));
     }
     /**
      * DebuggerStatement :
      *      debugger ;
      *
      * See 12.15
      *
      * Parse debugger statement.
      */
     private void  debuggerStatement() {
         // Capture DEBUGGER token.
         final int  debuggerLine  = line;
         final long debuggerToken = token;
         // DEBUGGER tested in caller.
         next();
         endOfLine();
         appendStatement(new ExpressionStatement(debuggerLine, debuggerToken, finish, new RuntimeNode(debuggerToken, finish, RuntimeNode.Request.DEBUGGER, new ArrayList<Expression>())));
     }
     /**
      * PrimaryExpression :
      *      this
      *      Identifier
      *      Literal
      *      ArrayLiteral
      *      ObjectLiteral
      *      ( Expression )
      *
      *  See 11.1
      *
      * Parse primary expression.
      * @return Expression node.
      */
     @SuppressWarnings("fallthrough")
     private Expression primaryExpression() {
         // Capture first token.
         final int  primaryLine  = line;
         final long primaryToken = token;
         switch (type) {
         case THIS:
             final String name = type.getName();
             next();
             lc.setFlag(lc.getCurrentFunction(), FunctionNode.USES_THIS);
             return new IdentNode(primaryToken, finish, name);
         case IDENT:
             final IdentNode ident = getIdent();
             if (ident == null) {
                 break;
             }
             detectSpecialProperty(ident);
             return ident;
         case OCTAL:
             if (isStrictMode) {
                throw error(AbstractParser.message("strict.no.octal"), token);
             }
         case STRING:
         case ESCSTRING:
         case DECIMAL:
         case HEXADECIMAL:
         case FLOATING:
         case REGEX:
         case XML:
             return getLiteral();
         case EXECSTRING:
             return execString(primaryLine, primaryToken);
         case FALSE:
             next();
             return LiteralNode.newInstance(primaryToken, finish, false);
         case TRUE:
             next();
             return LiteralNode.newInstance(primaryToken, finish, true);
         case NULL:
             next();
             return LiteralNode.newInstance(primaryToken, finish);
         case LBRACKET:
             return arrayLiteral();
         case LBRACE:
             return objectLiteral();
         case LPAREN:
             next();
             final Expression expression = expression();
             expect(RPAREN);
             return expression;
         default:
             // In this context some operator tokens mark the start of a literal.
             if (lexer.scanLiteral(primaryToken, type, lineInfoReceiver)) {
                 next();
                 return getLiteral();
             }
             if (isNonStrictModeIdent()) {
                 return getIdent();
             }
             break;
         }
         return null;
     }
     /**
      * Convert execString to a call to $EXEC.
      *
      * @param primaryToken Original string token.
      * @return callNode to $EXEC.
      */
     CallNode execString(final int primaryLine, final long primaryToken) {
         // Synthesize an ident to call $EXEC.
         final IdentNode execIdent = new IdentNode(primaryToken, finish, ScriptingFunctions.EXEC_NAME);
         // Skip over EXECSTRING.
         next();
         // Set up argument list for call.
         // Skip beginning of edit string expression.
         expect(LBRACE);
         // Add the following expression to arguments.
         final List<Expression> arguments = Collections.singletonList(expression());
         // Skip ending of edit string expression.
         expect(RBRACE);
         return new CallNode(primaryLine, primaryToken, finish, execIdent, arguments, false);
     }
     /**
      * ArrayLiteral :
      *      [ Elision? ]
      *      [ ElementList ]
      *      [ ElementList , Elision? ]
      *      [ expression for (LeftHandExpression in expression) ( (if ( Expression ) )? ]
      *
      * ElementList : Elision? AssignmentExpression
      *      ElementList , Elision? AssignmentExpression
      *
      * Elision :
      *      ,
      *      Elision ,
      *
      * See 12.1.4
      * JavaScript 1.8
      *
      * Parse array literal.
      * @return Expression node.
      */
     private LiteralNode<Expression[]> arrayLiteral() {
         // Capture LBRACKET token.
         final long arrayToken = token;
         // LBRACKET tested in caller.
         next();
         // Prepare to accummulating elements.
         final List<Expression> elements = new ArrayList<>();
         // Track elisions.
         boolean elision = true;
 loop:
         while (true) {
              switch (type) {
             case RBRACKET:
                 next();
                 break loop;
             case COMMARIGHT:
                 next();
                 // If no prior expression
                 if (elision) {
                     elements.add(null);
                 }
                 elision = true;
                 break;
             default:
                 if (!elision) {
                     throw error(AbstractParser.message("expected.comma", type.getNameOrType()));
                 }
                 // Add expression element.
                 final Expression expression = assignmentExpression(false);
                 if (expression != null) {
                     elements.add(expression);
                 } else {
                     expect(RBRACKET);
                 }
                 elision = false;
                 break;
             }
         }
         return LiteralNode.newInstance(arrayToken, finish, elements);
     }
     /**
      * ObjectLiteral :
      *      { }
      *      { PropertyNameAndValueList } { PropertyNameAndValueList , }
      *
      * PropertyNameAndValueList :
      *      PropertyAssignment
      *      PropertyNameAndValueList , PropertyAssignment
      *
      * See 11.1.5
      *
      * Parse an object literal.
      * @return Expression node.
      */
     private ObjectNode objectLiteral() {
         // Capture LBRACE token.
         final long objectToken = token;
         // LBRACE tested in caller.
         next();
         // Object context.
         // Prepare to accumulate elements.
         final List<PropertyNode> elements = new ArrayList<>();
         final Map<String, Integer> map = new HashMap<>();
         // Create a block for the object literal.
         boolean commaSeen = true;
 loop:
         while (true) {
             switch (type) {
                 case RBRACE:
                     next();
                     break loop;
                 case COMMARIGHT:
                     if (commaSeen) {
                         throw error(AbstractParser.message("expected.property.id", type.getNameOrType()));
                     }
                     next();
                     commaSeen = true;
                     break;
                 default:
                     if (!commaSeen) {
                         throw error(AbstractParser.message("expected.comma", type.getNameOrType()));
                     }
                     commaSeen = false;
                     // Get and add the next property.
                     final PropertyNode property = propertyAssignment();
                     final String key = property.getKeyName();
                     final Integer existing = map.get(key);
                     if (existing == null) {
                         map.put(key, elements.size());
                         elements.add(property);
                         break;
                     }
                     final PropertyNode existingProperty = elements.get(existing);
                     // ECMA section 11.1.5 Object Initialiser
                     // point # 4 on property assignment production
                     final Expression   value  = property.getValue();
                     final FunctionNode getter = property.getGetter();
                     final FunctionNode setter = property.getSetter();
                     final Expression   prevValue  = existingProperty.getValue();
                     final FunctionNode prevGetter = existingProperty.getGetter();
                     final FunctionNode prevSetter = existingProperty.getSetter();
                     // ECMA 11.1.5 strict mode restrictions
                     if (isStrictMode && value != null && prevValue != null) {
                         throw error(AbstractParser.message("property.redefinition", key), property.getToken());
                     }
                     final boolean isPrevAccessor = prevGetter != null || prevSetter != null;
                     final boolean isAccessor     = getter != null     || setter != null;
                     // data property redefined as accessor property
                     if (prevValue != null && isAccessor) {
                         throw error(AbstractParser.message("property.redefinition", key), property.getToken());
                     }
                     // accessor property redefined as data
                     if (isPrevAccessor && value != null) {
                         throw error(AbstractParser.message("property.redefinition", key), property.getToken());
                     }
                     if (isAccessor && isPrevAccessor) {
                         if (getter != null && prevGetter != null ||
                                 setter != null && prevSetter != null) {
                             throw error(AbstractParser.message("property.redefinition", key), property.getToken());
                         }
                     }
                     if (value != null) {
                         elements.add(property);
                     } else if (getter != null) {
                         elements.set(existing, existingProperty.setGetter(getter));
                     } else if (setter != null) {
                         elements.set(existing, existingProperty.setSetter(setter));
                     }
                     break;
             }
         }
         return new ObjectNode(objectToken, finish, elements);
     }
     /**
      * PropertyName :
      *      IdentifierName
      *      StringLiteral
      *      NumericLiteral
      *
      * See 11.1.5
      *
      * @return PropertyName node
      */
     @SuppressWarnings("fallthrough")
     private PropertyKey propertyName() {
         switch (type) {
         case IDENT:
             return getIdent().setIsPropertyName();
         case OCTAL:
             if (isStrictMode) {
                 throw error(AbstractParser.message("strict.no.octal"), token);
             }
         case STRING:
         case ESCSTRING:
         case DECIMAL:
         case HEXADECIMAL:
         case FLOATING:
             return getLiteral();
         default:
             return getIdentifierName().setIsPropertyName();
         }
     }
     /**
      * PropertyAssignment :
      *      PropertyName : AssignmentExpression
      *      get PropertyName ( ) { FunctionBody }
      *      set PropertyName ( PropertySetParameterList ) { FunctionBody }
      *
      * PropertySetParameterList :
      *      Identifier
      *
      * PropertyName :
      *      IdentifierName
      *      StringLiteral
      *      NumericLiteral
      *
      * See 11.1.5
      *
      * Parse an object literal property.
      * @return Property or reference node.
      */
     private PropertyNode propertyAssignment() {
         // Capture firstToken.
         final long propertyToken = token;
         final int  functionLine  = line;
         PropertyKey propertyName;
         if (type == IDENT) {
             // Get IDENT.
             final String ident = (String)expectValue(IDENT);
             if (type != COLON) {
                 final long getSetToken = propertyToken;
                 switch (ident) {
                 case "get":
                     final PropertyFunction getter = propertyGetterFunction(getSetToken, functionLine);
                     return new PropertyNode(propertyToken, finish, getter.ident, null, getter.functionNode, null);
                 case "set":
                     final PropertyFunction setter = propertySetterFunction(getSetToken, functionLine);
                     return new PropertyNode(propertyToken, finish, setter.ident, null, null, setter.functionNode);
                 default:
                     break;
                 }
             }
             propertyName =  createIdentNode(propertyToken, finish, ident).setIsPropertyName();
         } else {
             propertyName = propertyName();
         }
         expect(COLON);
         defaultNames.push(propertyName);
         try {
             return new PropertyNode(propertyToken, finish, propertyName, assignmentExpression(false), null, null);
         } finally {
             defaultNames.pop();
         }
     }
     private PropertyFunction propertyGetterFunction(final long getSetToken, final int functionLine) {
         final PropertyKey getIdent = propertyName();
         final String getterName = getIdent.getPropertyName();
         final IdentNode getNameNode = createIdentNode(((Node)getIdent).getToken(), finish, NameCodec.encode("get " + getterName));
         expect(LPAREN);
         expect(RPAREN);
         final FunctionNode functionNode = functionBody(getSetToken, getNameNode, new ArrayList<IdentNode>(), FunctionNode.Kind.GETTER, functionLine);
         return new PropertyFunction(getIdent, functionNode);
     }
     private PropertyFunction propertySetterFunction(final long getSetToken, final int functionLine) {
         final PropertyKey setIdent = propertyName();
         final String setterName = setIdent.getPropertyName();
         final IdentNode setNameNode = createIdentNode(((Node)setIdent).getToken(), finish, NameCodec.encode("set " + setterName));
         expect(LPAREN);
         // be sloppy and allow missing setter parameter even though
         // spec does not permit it!
         final IdentNode argIdent;
         if (type == IDENT || isNonStrictModeIdent()) {
             argIdent = getIdent();
             verifyStrictIdent(argIdent, "setter argument");
         } else {
             argIdent = null;
         }
         expect(RPAREN);
         final List<IdentNode> parameters = new ArrayList<>();
         if (argIdent != null) {
             parameters.add(argIdent);
         }
         final FunctionNode functionNode = functionBody(getSetToken, setNameNode, parameters, FunctionNode.Kind.SETTER, functionLine);
         return new PropertyFunction(setIdent, functionNode);
     }
     private static class PropertyFunction {
         final PropertyKey ident;
         final FunctionNode functionNode;
         PropertyFunction(final PropertyKey ident, final FunctionNode function) {
             this.ident = ident;
             this.functionNode = function;
         }
     }
     /**
      * LeftHandSideExpression :
      *      NewExpression
      *      CallExpression
      *
      * CallExpression :
      *      MemberExpression Arguments
      *      CallExpression Arguments
      *      CallExpression [ Expression ]
      *      CallExpression . IdentifierName
      *
      * See 11.2
      *
      * Parse left hand side expression.
      * @return Expression node.
      */
     private Expression leftHandSideExpression() {
         int  callLine  = line;
         long callToken = token;
         Expression lhs = memberExpression();
         if (type == LPAREN) {
             final List<Expression> arguments = optimizeList(argumentList());
             // Catch special functions.
             if (lhs instanceof IdentNode) {
                 detectSpecialFunction((IdentNode)lhs);
             }
             lhs = new CallNode(callLine, callToken, finish, lhs, arguments, false);
         }
 loop:
         while (true) {
             // Capture token.
             callLine  = line;
             callToken = token;
             switch (type) {
             case LPAREN:
                 // Get NEW or FUNCTION arguments.
                 final List<Expression> arguments = optimizeList(argumentList());
                 // Create call node.
                 lhs = new CallNode(callLine, callToken, finish, lhs, arguments, false);
                 break;
             case LBRACKET:
                 next();
                 // Get array index.
                 final Expression rhs = expression();
                 expect(RBRACKET);
                 // Create indexing node.
                 lhs = new IndexNode(callToken, finish, lhs, rhs);
                 break;
             case PERIOD:
                 next();
                 final IdentNode property = getIdentifierName();
                 // Create property access node.
                 lhs = new AccessNode(callToken, finish, lhs, property.getName());
                 break;
             default:
                 break loop;
             }
         }
         return lhs;
     }
     /**
      * NewExpression :
      *      MemberExpression
      *      new NewExpression
      *
      * See 11.2
      *
      * Parse new expression.
      * @return Expression node.
      */
     private Expression newExpression() {
         final long newToken = token;
         // NEW is tested in caller.
         next();
         // Get function base.
         final int  callLine    = line;
         final Expression constructor = memberExpression();
         if (constructor == null) {
             return null;
         }
         // Get arguments.
         ArrayList<Expression> arguments;
         // Allow for missing arguments.
         if (type == LPAREN) {
             arguments = argumentList();
         } else {
             arguments = new ArrayList<>();
         }
         // Nashorn extension: This is to support the following interface implementation
         // syntax:
         //
         //     var r = new java.lang.Runnable() {
         //         run: function() { println("run"); }
         //     };
         //
         // The object literal following the "new Constructor()" expresssion
         // is passed as an additional (last) argument to the constructor.
         if (!env._no_syntax_extensions && type == LBRACE) {
             arguments.add(objectLiteral());
         }
         final CallNode callNode = new CallNode(callLine, constructor.getToken(), finish, constructor, optimizeList(arguments), true);
         return new UnaryNode(newToken, callNode);
     }
     /**
      * MemberExpression :
      *      PrimaryExpression
      *      FunctionExpression
      *      MemberExpression [ Expression ]
      *      MemberExpression . IdentifierName
      *      new MemberExpression Arguments
      *
      * See 11.2
      *
      * Parse member expression.
      * @return Expression node.
      */
     private Expression memberExpression() {
         // Prepare to build operation.
         Expression lhs;
         switch (type) {
         case NEW:
             // Get new expression.
             lhs = newExpression();
             break;
         case FUNCTION:
             // Get function expression.
             lhs = functionExpression(false, false);
             break;
         default:
             // Get primary expression.
             lhs = primaryExpression();
             break;
         }
 loop:
         while (true) {
             // Capture token.
             final long callToken = token;
             switch (type) {
             case LBRACKET:
                 next();
                 // Get array index.
                 final Expression index = expression();
                 expect(RBRACKET);
                 // Create indexing node.
                 lhs = new IndexNode(callToken, finish, lhs, index);
                 break;
             case PERIOD:
                 if (lhs == null) {
                     throw error(AbstractParser.message("expected.operand", type.getNameOrType()));
                 }
                 next();
                 final IdentNode property = getIdentifierName();
                 // Create property access node.
                 lhs = new AccessNode(callToken, finish, lhs, property.getName());
                 break;
             default:
                 break loop;
             }
         }
         return lhs;
     }
     /**
      * Arguments :
      *      ( )
      *      ( ArgumentList )
      *
      * ArgumentList :
      *      AssignmentExpression
      *      ArgumentList , AssignmentExpression
      *
      * See 11.2
      *
      * Parse function call arguments.
      * @return Argument list.
      */
     private ArrayList<Expression> argumentList() {
         // Prepare to accumulate list of arguments.
         final ArrayList<Expression> nodeList = new ArrayList<>();
         // LPAREN tested in caller.
         next();
         // Track commas.
         boolean first = true;
         while (type != RPAREN) {
             // Comma prior to every argument except the first.
             if (!first) {
                 expect(COMMARIGHT);
             } else {
                 first = false;
             }
             // Get argument expression.
             nodeList.add(assignmentExpression(false));
         }
         expect(RPAREN);
         return nodeList;
     }
     private static <T> List<T> optimizeList(final ArrayList<T> list) {
         switch(list.size()) {
             case 0: {
                 return Collections.emptyList();
             }
             case 1: {
                 return Collections.singletonList(list.get(0));
             }
             default: {
                 list.trimToSize();
                 return list;
             }
         }
     }
     /**
      * FunctionDeclaration :
      *      function Identifier ( FormalParameterList? ) { FunctionBody }
      *
      * FunctionExpression :
      *      function Identifier? ( FormalParameterList? ) { FunctionBody }
      *
      * See 13
      *
      * Parse function declaration.
      * @param isStatement True if for is a statement.
      *
      * @return Expression node.
      */
     private Expression functionExpression(final boolean isStatement, final boolean topLevel) {
         final long functionToken = token;
         final int  functionLine  = line;
         // FUNCTION is tested in caller.
         next();
         IdentNode name = null;
         if (type == IDENT || isNonStrictModeIdent()) {
             name = getIdent();
             verifyStrictIdent(name, "function name");
         } else if (isStatement) {
             // Nashorn extension: anonymous function statements
             if (env._no_syntax_extensions) {
                 expect(IDENT);
             }
         }
         // name is null, generate anonymous name
         boolean isAnonymous = false;
         if (name == null) {
             final String tmpName = getDefaultValidFunctionName(functionLine);
             name = new IdentNode(functionToken, Token.descPosition(functionToken), tmpName);
             isAnonymous = true;
         }
         expect(LPAREN);
         final List<IdentNode> parameters = formalParameterList();
         expect(RPAREN);
         FunctionNode functionNode = functionBody(functionToken, name, parameters, FunctionNode.Kind.NORMAL, functionLine);
         if (isStatement) {
             if (topLevel) {
                 functionNode = functionNode.setFlag(lc, FunctionNode.IS_DECLARED);
             } else if (isStrictMode) {
                 throw error(JSErrorType.SYNTAX_ERROR, AbstractParser.message("strict.no.func.decl.here"), functionToken);
             } else if (env._function_statement == ScriptEnvironment.FunctionStatementBehavior.ERROR) {
                 throw error(JSErrorType.SYNTAX_ERROR, AbstractParser.message("no.func.decl.here"), functionToken);
             } else if (env._function_statement == ScriptEnvironment.FunctionStatementBehavior.WARNING) {
                 warning(JSErrorType.SYNTAX_ERROR, AbstractParser.message("no.func.decl.here.warn"), functionToken);
             }
             if (isArguments(name)) {
                 lc.setFlag(lc.getCurrentFunction(), FunctionNode.DEFINES_ARGUMENTS);
             }
         }
         if (isAnonymous) {
             functionNode = functionNode.setFlag(lc, FunctionNode.IS_ANONYMOUS);
         }
         final int arity = parameters.size();
         final boolean strict = functionNode.isStrict();
         if (arity > 1) {
             final HashSet<String> parametersSet = new HashSet<>(arity);
             for (int i = arity - 1; i >= 0; i--) {
                 final IdentNode parameter = parameters.get(i);
                 String parameterName = parameter.getName();
                 if (isArguments(parameterName)) {
                     functionNode = functionNode.setFlag(lc, FunctionNode.DEFINES_ARGUMENTS);
                 }
                 if (parametersSet.contains(parameterName)) {
                     // redefinition of parameter name
                     if (strict) {
                         throw error(AbstractParser.message("strict.param.redefinition", parameterName), parameter.getToken());
                     }
                     // rename in non-strict mode
                     parameterName = functionNode.uniqueName(parameterName);
                     final long parameterToken = parameter.getToken();
                     parameters.set(i, new IdentNode(parameterToken, Token.descPosition(parameterToken), functionNode.uniqueName(parameterName)));
                 }
                 parametersSet.add(parameterName);
             }
         } else if (arity == 1) {
             if (isArguments(parameters.get(0))) {
                 functionNode = functionNode.setFlag(lc, FunctionNode.DEFINES_ARGUMENTS);
             }
         }
         if (isStatement) {
             final VarNode varNode = new VarNode(functionLine, functionToken, finish, name, functionNode, VarNode.IS_STATEMENT);
             if (topLevel) {
                 functionDeclarations.add(varNode);
             } else {
                 appendStatement(varNode);
             }
         }
         return functionNode;
     }
     private String getDefaultValidFunctionName(final int functionLine) {
         final String defaultFunctionName = getDefaultFunctionName();
         return isValidIdentifier(defaultFunctionName) ? defaultFunctionName : ANON_FUNCTION_PREFIX.symbolName() + functionLine;
     }
     private static boolean isValidIdentifier(final String name) {
         if(name == null || name.isEmpty()) {
             return false;
         }
         if(!Character.isJavaIdentifierStart(name.charAt(0))) {
             return false;
         }
         for(int i = 1; i < name.length(); ++i) {
             if(!Character.isJavaIdentifierPart(name.charAt(i))) {
                 return false;
             }
         }
         return true;
     }
     private String getDefaultFunctionName() {
         if(!defaultNames.isEmpty()) {
             final Object nameExpr = defaultNames.peek();
             if(nameExpr instanceof PropertyKey) {
                 markDefaultNameUsed();
                 return ((PropertyKey)nameExpr).getPropertyName();
             } else if(nameExpr instanceof AccessNode) {
                 markDefaultNameUsed();
                 return ((AccessNode)nameExpr).getProperty();
             }
         }
         return null;
     }
     private void markDefaultNameUsed() {
         defaultNames.pop();
         // Can be any value as long as getDefaultFunctionName doesn't recognize it as something it can extract a value
         // from. Can't be null
         defaultNames.push("");
     }
     /**
      * FormalParameterList :
      *      Identifier
      *      FormalParameterList , Identifier
      *
      * See 13
      *
      * Parse function parameter list.
      * @return List of parameter nodes.
      */
     private List<IdentNode> formalParameterList() {
         return formalParameterList(RPAREN);
     }
     /**
      * Same as the other method of the same name - except that the end
      * token type expected is passed as argument to this method.
      *
      * FormalParameterList :
      *      Identifier
      *      FormalParameterList , Identifier
      *
      * See 13
      *
      * Parse function parameter list.
      * @return List of parameter nodes.
      */
     private List<IdentNode> formalParameterList(final TokenType endType) {
         // Prepare to gather parameters.
         final ArrayList<IdentNode> parameters = new ArrayList<>();
         // Track commas.
         boolean first = true;
         while (type != endType) {
             // Comma prior to every argument except the first.
             if (!first) {
                 expect(COMMARIGHT);
             } else {
                 first = false;
             }
             // Get and add parameter.
             final IdentNode ident = getIdent();
             // ECMA 13.1 strict mode restrictions
             verifyStrictIdent(ident, "function parameter");
             parameters.add(ident);
         }
         parameters.trimToSize();
         return parameters;
     }
     /**
      * FunctionBody :
      *      SourceElements?
      *
      * See 13
      *
      * Parse function body.
      * @return function node (body.)
      */
     private FunctionNode functionBody(final long firstToken, final IdentNode ident, final List<IdentNode> parameters, final FunctionNode.Kind kind, final int functionLine) {
         FunctionNode functionNode = null;
         long lastToken = 0L;
         try {
             // Create a new function block.
             functionNode = newFunctionNode(firstToken, ident, parameters, kind, functionLine);
             // Nashorn extension: expression closures
             if (!env._no_syntax_extensions && type != LBRACE) {
                 /*
                  * Example:
                  *
                  * function square(x) x * x;
                  * print(square(3));
                  */
                 // just expression as function body
                 final Expression expr = assignmentExpression(true);
                 lastToken = previousToken;
                 assert lc.getCurrentBlock() == lc.getFunctionBody(functionNode);
                 // EOL uses length field to store the line number
                 final int lastFinish = Token.descPosition(lastToken) + (Token.descType(lastToken) == EOL ? 0 : Token.descLength(lastToken));
                 final ReturnNode returnNode = new ReturnNode(functionNode.getLineNumber(), expr.getToken(), lastFinish, expr);
                 appendStatement(returnNode);
                 functionNode.setFinish(lastFinish);
             } else {
                 expect(LBRACE);
                 // Gather the function elements.
                 final List<Statement> prevFunctionDecls = functionDeclarations;
                 functionDeclarations = new ArrayList<>();
                 try {
                     sourceElements(false);
                     addFunctionDeclarations(functionNode);
                 } finally {
                     functionDeclarations = prevFunctionDecls;
                 }
                 lastToken = token;
                 expect(RBRACE);
                 functionNode.setFinish(finish);
             }
         } finally {
             functionNode = restoreFunctionNode(functionNode, lastToken);
         }
         printAST(functionNode);
         return functionNode;
     }
     private void printAST(final FunctionNode functionNode) {
         if (functionNode.getFlag(FunctionNode.IS_PRINT_AST)) {
             env.getErr().println(new ASTWriter(functionNode));
         }
         if (functionNode.getFlag(FunctionNode.IS_PRINT_PARSE)) {
             env.getErr().println(new PrintVisitor(functionNode, true, false));
         }
     }
     private void addFunctionDeclarations(final FunctionNode functionNode) {
         assert lc.peek() == lc.getFunctionBody(functionNode);
         VarNode lastDecl = null;
         for (int i = functionDeclarations.size() - 1; i >= 0; i--) {
             Statement decl = functionDeclarations.get(i);
             if (lastDecl == null && decl instanceof VarNode) {
                 decl = lastDecl = ((VarNode)decl).setFlag(VarNode.IS_LAST_FUNCTION_DECLARATION);
                 lc.setFlag(functionNode, FunctionNode.HAS_FUNCTION_DECLARATIONS);
             }
             prependStatement(decl);
         }
     }
     private RuntimeNode referenceError(final Expression lhs, final Expression rhs, final boolean earlyError) {
         if (earlyError) {
             throw error(JSErrorType.REFERENCE_ERROR, AbstractParser.message("invalid.lvalue"), lhs.getToken());
         }
         final ArrayList<Expression> args = new ArrayList<>();
         args.add(lhs);
         if (rhs == null) {
             args.add(LiteralNode.newInstance(lhs.getToken(), lhs.getFinish()));
         } else {
             args.add(rhs);
         }
         args.add(LiteralNode.newInstance(lhs.getToken(), lhs.getFinish(), lhs.toString()));
         return new RuntimeNode(lhs.getToken(), lhs.getFinish(), RuntimeNode.Request.REFERENCE_ERROR, args);
     }
     /*
      * parse LHS [a, b, ..., c].
      *
      * JavaScript 1.8.
      */
     //private Node destructureExpression() {
     //    return null;
     //}
     /**
      * PostfixExpression :
      *      LeftHandSideExpression
      *      LeftHandSideExpression ++ // [no LineTerminator here]
      *      LeftHandSideExpression -- // [no LineTerminator here]
      *
      * See 11.3
      *
      * UnaryExpression :
      *      PostfixExpression
      *      delete UnaryExpression
      *      Node UnaryExpression
      *      typeof UnaryExpression
      *      ++ UnaryExpression
      *      -- UnaryExpression
      *      + UnaryExpression
      *      - UnaryExpression
      *      ~ UnaryExpression
      *      ! UnaryExpression
      *
      * See 11.4
      *
      * Parse unary expression.
      * @return Expression node.
      */
     private Expression unaryExpression() {
         final int  unaryLine  = line;
         final long unaryToken = token;
         switch (type) {
         case DELETE: {
             next();
             final Expression expr = unaryExpression();
             if (expr instanceof BaseNode || expr instanceof IdentNode) {
                 return new UnaryNode(unaryToken, expr);
             }
             appendStatement(new ExpressionStatement(unaryLine, unaryToken, finish, expr));
             return LiteralNode.newInstance(unaryToken, finish, true);
         }
         case VOID:
         case TYPEOF:
         case ADD:
         case SUB:
         case BIT_NOT:
         case NOT:
             next();
             final Expression expr = unaryExpression();
             return new UnaryNode(unaryToken, expr);
         case INCPREFIX:
         case DECPREFIX:
             final TokenType opType = type;
             next();
             final Expression lhs = leftHandSideExpression();
             // ++, -- without operand..
             if (lhs == null) {
                 throw error(AbstractParser.message("expected.lvalue", type.getNameOrType()));
             }
             if (!(lhs instanceof AccessNode ||
                   lhs instanceof IndexNode ||
                   lhs instanceof IdentNode)) {
                 return referenceError(lhs, null, env._early_lvalue_error);
             }
             if (lhs instanceof IdentNode) {
                 if (!checkIdentLValue((IdentNode)lhs)) {
                     return referenceError(lhs, null, false);
                 }
                 verifyStrictIdent((IdentNode)lhs, "operand for " + opType.getName() + " operator");
             }
             return incDecExpression(unaryToken, opType, lhs, false);
         default:
             break;
         }
         Expression expression = leftHandSideExpression();
         if (last != EOL) {
             switch (type) {
             case INCPREFIX:
             case DECPREFIX:
                 final TokenType opType = type;
                 final Expression lhs = expression;
                 // ++, -- without operand..
                 if (lhs == null) {
                     throw error(AbstractParser.message("expected.lvalue", type.getNameOrType()));
                 }
                 if (!(lhs instanceof AccessNode ||
                    lhs instanceof IndexNode ||
                    lhs instanceof IdentNode)) {
                     next();
                     return referenceError(lhs, null, env._early_lvalue_error);
                 }
                 if (lhs instanceof IdentNode) {
                     if (!checkIdentLValue((IdentNode)lhs)) {
                         next();
                         return referenceError(lhs, null, false);
                     }
                     verifyStrictIdent((IdentNode)lhs, "operand for " + opType.getName() + " operator");
                 }
                 expression = incDecExpression(token, type, expression, true);
                 next();
                 break;
             default:
                 break;
             }
         }
         if (expression == null) {
             throw error(AbstractParser.message("expected.operand", type.getNameOrType()));
         }
         return expression;
     }
     /**
      * MultiplicativeExpression :
      *      UnaryExpression
      *      MultiplicativeExpression * UnaryExpression
      *      MultiplicativeExpression / UnaryExpression
      *      MultiplicativeExpression % UnaryExpression
      *
      * See 11.5
      *
      * AdditiveExpression :
      *      MultiplicativeExpression
      *      AdditiveExpression + MultiplicativeExpression
      *      AdditiveExpression - MultiplicativeExpression
      *
      * See 11.6
      *
      * ShiftExpression :
      *      AdditiveExpression
      *      ShiftExpression << AdditiveExpression
      *      ShiftExpression >> AdditiveExpression
      *      ShiftExpression >>> AdditiveExpression
      *
      * See 11.7
      *
      * RelationalExpression :
      *      ShiftExpression
      *      RelationalExpression < ShiftExpression
      *      RelationalExpression > ShiftExpression
      *      RelationalExpression <= ShiftExpression
      *      RelationalExpression >= ShiftExpression
      *      RelationalExpression instanceof ShiftExpression
      *      RelationalExpression in ShiftExpression // if !noIf
      *
      * See 11.8
      *
      *      RelationalExpression
      *      EqualityExpression == RelationalExpression
      *      EqualityExpression != RelationalExpression
      *      EqualityExpression === RelationalExpression
      *      EqualityExpression !== RelationalExpression
      *
      * See 11.9
      *
      * BitwiseANDExpression :
      *      EqualityExpression
      *      BitwiseANDExpression & EqualityExpression
      *
      * BitwiseXORExpression :
      *      BitwiseANDExpression
      *      BitwiseXORExpression ^ BitwiseANDExpression
      *
      * BitwiseORExpression :
      *      BitwiseXORExpression
      *      BitwiseORExpression | BitwiseXORExpression
      *
      * See 11.10
      *
      * LogicalANDExpression :
      *      BitwiseORExpression
      *      LogicalANDExpression && BitwiseORExpression
      *
      * LogicalORExpression :
      *      LogicalANDExpression
      *      LogicalORExpression || LogicalANDExpression
      *
      * See 11.11
      *
      * ConditionalExpression :
      *      LogicalORExpression
      *      LogicalORExpression ? AssignmentExpression : AssignmentExpression
      *
      * See 11.12
      *
      * AssignmentExpression :
      *      ConditionalExpression
      *      LeftHandSideExpression AssignmentOperator AssignmentExpression
      *
      * AssignmentOperator :
      *      = *= /= %= += -= <<= >>= >>>= &= ^= |=
      *
      * See 11.13
      *
      * Expression :
      *      AssignmentExpression
      *      Expression , AssignmentExpression
      *
      * See 11.14
      *
      * Parse expression.
      * @return Expression node.
      */
     private Expression expression() {
         // TODO - Destructuring array.
         // Include commas in expression parsing.
         return expression(unaryExpression(), COMMARIGHT.getPrecedence(), false);
     }
     private JoinPredecessorExpression joinPredecessorExpression() {
         return new JoinPredecessorExpression(expression());
     }
     private Expression expression(final Expression exprLhs, final int minPrecedence, final boolean noIn) {
         // Get the precedence of the next operator.
         int precedence = type.getPrecedence();
         Expression lhs = exprLhs;
         // While greater precedence.
         while (type.isOperator(noIn) && precedence >= minPrecedence) {
             // Capture the operator token.
             final long op = token;
             if (type == TERNARY) {
                 // Skip operator.
                 next();
                 // Pass expression. Middle expression of a conditional expression can be a "in"
                 // expression - even in the contexts where "in" is not permitted.
                 final Expression trueExpr = expression(unaryExpression(), ASSIGN.getPrecedence(), false);
                 expect(COLON);
                 // Fail expression.
                 final Expression falseExpr = expression(unaryExpression(), ASSIGN.getPrecedence(), noIn);
                 // Build up node.
                 lhs = new TernaryNode(op, lhs, new JoinPredecessorExpression(trueExpr), new JoinPredecessorExpression(falseExpr));
             } else {
                 // Skip operator.
                 next();
                  // Get the next primary expression.
                 Expression rhs;
                 final boolean isAssign = Token.descType(op) == ASSIGN;
                 if(isAssign) {
                     defaultNames.push(lhs);
                 }
                 try {
                     rhs = unaryExpression();
                     // Get precedence of next operator.
                     int nextPrecedence = type.getPrecedence();
                     // Subtask greater precedence.
                     while (type.isOperator(noIn) &&
                            (nextPrecedence > precedence ||
                            nextPrecedence == precedence && !type.isLeftAssociative())) {
                         rhs = expression(rhs, nextPrecedence, noIn);
                         nextPrecedence = type.getPrecedence();
                     }
                 } finally {
                     if(isAssign) {
                         defaultNames.pop();
                     }
                 }
                 lhs = verifyAssignment(op, lhs, rhs);
             }
             precedence = type.getPrecedence();
         }
         return lhs;
     }
     private Expression assignmentExpression(final boolean noIn) {
         // TODO - Handle decompose.
         // Exclude commas in expression parsing.
         return expression(unaryExpression(), ASSIGN.getPrecedence(), noIn);
     }
     /**
      * Parse an end of line.
      */
     private void endOfLine() {
         switch (type) {
         case SEMICOLON:
         case EOL:
             next();
             break;
         case RPAREN:
         case RBRACKET:
         case RBRACE:
         case EOF:
             break;
         default:
             if (last != EOL) {
                 expect(SEMICOLON);
             }
             break;
         }
     }
     @Override
     public String toString() {
         return "'JavaScript Parsing'";
     }
     private static void markEval(final LexicalContext lc) {
         final Iterator<FunctionNode> iter = lc.getFunctions();
         boolean flaggedCurrentFn = false;
         while (iter.hasNext()) {
             final FunctionNode fn = iter.next();
             if (!flaggedCurrentFn) {
                 lc.setFlag(fn, FunctionNode.HAS_EVAL);
                 flaggedCurrentFn = true;
             } else {
                 lc.setFlag(fn, FunctionNode.HAS_NESTED_EVAL);
             }
             lc.setBlockNeedsScope(lc.getFunctionBody(fn));
         }
     }
     private void prependStatement(final Statement statement) {
         lc.prependStatement(statement);
     }
     private void appendStatement(final Statement statement) {
         lc.appendStatement(statement);
     }
 }

Mercurial > jdk8-mips64-public > nashorn / annotate

src/jdk/nashorn/internal/parser/Parser.java@85e3f07fc5fc (annotated)

src/jdk/nashorn/internal/parser/Parser.java