示例#1
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        private static int RelocateVar(JsBlock block, int insertAt, JsVar varStatement)
        {
            // if the var statement is at the next position to insert, then we don't need
            // to do anything.
            if (block[insertAt] != varStatement)
            {
                // check to see if the current position is a var and we are the NEXT statement.
                // if that's the case, we don't need to break out the initializer, just append all the
                // vardecls as-is to the current position.
                var existingVar = block[insertAt] as JsVar;
                if (existingVar != null && block[insertAt + 1] == varStatement)
                {
                    // just append our vardecls to the insertion point, then delete our statement
                    existingVar.Append(varStatement);
                    block.RemoveAt(insertAt + 1);
                }
                else
                {
                    // iterate through the decls and count how many have initializers
                    var initializerCount = 0;
                    for (var ndx = 0; ndx < varStatement.Count; ++ndx)
                    {
                        if (varStatement[ndx].Initializer != null)
                        {
                            ++initializerCount;
                        }
                    }

                    // if there are more than two decls with initializers, then we won't actually
                    // be gaining anything by moving the var to the top. We'll get rid of the four
                    // bytes for the "var ", but we'll be adding two bytes for the name and comma
                    // because name=init will still need to remain behind.
                    if (initializerCount <= 2)
                    {
                        // first iterate through all the declarations in the var statement,
                        // constructing an expression statement that is made up of assignment
                        // operators for each of the declarations that have initializers (if any)
                        // and removing all the initializers
                        var assignments = new List <JsAstNode>();
                        for (var ndx = 0; ndx < varStatement.Count; ++ndx)
                        {
                            var varDecl = varStatement[ndx];
                            if (varDecl.Initializer != null)
                            {
                                if (varDecl.IsCCSpecialCase)
                                {
                                    // create a vardecl with the same name and no initializer
                                    var copyDecl = new JsVariableDeclaration(varDecl.Context, varDecl.Parser)
                                    {
                                        Identifier    = varDecl.Identifier,
                                        NameContext   = varDecl.VariableField.OriginalContext,
                                        VariableField = varDecl.VariableField
                                    };

                                    // replace the special vardecl with the copy
                                    varStatement[ndx] = copyDecl;

                                    // add the original vardecl to the list of "assignments"
                                    assignments.Add(varDecl);

                                    // add the new decl to the field's declaration list, and remove the old one
                                    // because we're going to change that to an assignment.
                                    varDecl.VariableField.Declarations.Add(copyDecl);
                                    varDecl.VariableField.Declarations.Remove(varDecl);
                                }
                                else
                                {
                                    // hold on to the object so we don't lose it to the GC
                                    var initializer = varDecl.Initializer;

                                    // remove it from the vardecl
                                    varDecl.Initializer = null;

                                    // create an assignment operator for a lookup to the name
                                    // as the left, and the initializer as the right, and add it to the list
                                    var lookup = new JsLookup(varDecl.VariableField.OriginalContext, varDecl.Parser)
                                    {
                                        Name          = varDecl.Identifier,
                                        VariableField = varDecl.VariableField,
                                    };
                                    assignments.Add(new JsBinaryOperator(varDecl.Context, varDecl.Parser)
                                    {
                                        Operand1        = lookup,
                                        Operand2        = initializer,
                                        OperatorToken   = JsToken.Assign,
                                        OperatorContext = varDecl.AssignContext
                                    });

                                    // add the new lookup to the field's references
                                    varDecl.VariableField.References.Add(lookup);
                                }
                            }
                        }

                        // now if there were any initializers...
                        if (assignments.Count > 0)
                        {
                            // we want to create one big expression from all the assignments and replace the
                            // var statement with the assignment(s) expression. Start at position n=1 and create
                            // a binary operator of n-1 as the left, n as the right, and using a comma operator.
                            var expression = assignments[0];
                            for (var ndx = 1; ndx < assignments.Count; ++ndx)
                            {
                                expression = JsCommaOperator.CombineWithComma(null, expression.Parser, expression, assignments[ndx]);
                            }

                            // replace the var with the expression.
                            // we still have a pointer to the var, so we can insert it back into the proper
                            // place next.
                            varStatement.Parent.ReplaceChild(varStatement, expression);
                        }
                        else
                        {
                            // no initializers.
                            // if the parent is a for-in statement...
                            var forInParent = varStatement.Parent as JsForIn;
                            if (forInParent != null)
                            {
                                // we want to replace the var statement with a lookup for the var
                                // there should be only one vardecl
                                var varDecl = varStatement[0];
                                var lookup  = new JsLookup(varDecl.VariableField.OriginalContext, varStatement.Parser)
                                {
                                    Name          = varDecl.Identifier,
                                    VariableField = varDecl.VariableField
                                };
                                varStatement.Parent.ReplaceChild(varStatement, lookup);
                                varDecl.VariableField.References.Add(lookup);
                            }
                            else
                            {
                                // just remove the var statement altogether
                                varStatement.Parent.ReplaceChild(varStatement, null);
                            }
                        }

                        // if the statement at the insertion point is a var-statement already,
                        // then we just need to append our vardecls to it. Otherwise we'll insert our
                        // var statement at the right point
                        if (existingVar != null)
                        {
                            // append the varstatement we want to move to the existing var, which will
                            // transfer all the vardecls to it.
                            existingVar.Append(varStatement);
                        }
                        else
                        {
                            // move the var to the insert point, incrementing the position or next time
                            block.Insert(insertAt, varStatement);
                        }
                    }
                }
            }

            return(insertAt);
        }
        public static JsAstNode CombineWithComma(JsContext context, JsParser parser, JsAstNode operand1, JsAstNode operand2)
        {
            var comma = new JsCommaOperator(context, parser);

            // if the left is a comma-operator already....
            var leftBinary = operand1 as JsBinaryOperator;
            var rightBinary = operand2 as JsBinaryOperator;
            if (leftBinary != null && leftBinary.OperatorToken == JsToken.Comma)
            {
                // the left-hand side is already a comma operator. Instead of nesting these, we're
                // going to combine them
                // move the old list's left-hand side to our left-hand side
                comma.Operand1 = leftBinary.Operand1;

                JsAstNodeList list;
                if (rightBinary != null && rightBinary.OperatorToken == JsToken.Comma)
                {
                    // the right is ALSO a comma operator. Create a new list, append all the rest of the operands
                    // and set our right-hand side to be the list
                    list = new JsAstNodeList(null, parser);
                    list.Append(leftBinary.Operand2).Append(rightBinary.Operand1).Append(rightBinary.Operand2);
                }
                else
                {
                    // the right is not a comma operator.
                    // see if the left-hand side already has a list we can use
                    list = leftBinary.Operand2 as JsAstNodeList;
                    if (list == null)
                    {
                        // it's not a list already
                        // create a new list with the left's right and our right and set it to our right
                        list = new JsAstNodeList(null, parser);
                        list.Append(leftBinary.Operand2);
                    }

                    // and add our right-hand operand to the end of the list
                    list.Append(operand2);
                }

                // set the list on the right
                comma.Operand2 = list;
            }
            else if (rightBinary != null && rightBinary.OperatorToken == JsToken.Comma)
            {
                // the left hand side is NOT a comma operator.
                comma.Operand1 = operand1;

                // the right-hand side is already a comma-operator, but the left is not.
                // see if it already has a list we can reuse
                var rightList = rightBinary.Operand2 as JsAstNodeList;
                if (rightList != null)
                {
                    // it does. Prepend its right-hand operand and use the list
                    rightList.Insert(0, rightBinary.Operand1);
                }
                else
                {
                    // it's not -- create a new list containing the operands
                    rightList = new JsAstNodeList(rightBinary.Context, parser);
                    rightList.Append(rightBinary.Operand1);
                    rightList.Append(rightBinary.Operand2);
                }

                comma.Operand2 = rightList;
            }
            else
            {
                comma.Operand1 = operand1;
                comma.Operand2 = operand2;
            }

            return comma;
        }
        public static JsAstNode CombineWithComma(JsContext context, JsParser parser, JsAstNode operand1, JsAstNode operand2)
        {
            var comma = new JsCommaOperator(context, parser);

            // if the left is a comma-operator already....
            var leftBinary  = operand1 as JsBinaryOperator;
            var rightBinary = operand2 as JsBinaryOperator;

            if (leftBinary != null && leftBinary.OperatorToken == JsToken.Comma)
            {
                // the left-hand side is already a comma operator. Instead of nesting these, we're
                // going to combine them
                // move the old list's left-hand side to our left-hand side
                comma.Operand1 = leftBinary.Operand1;

                JsAstNodeList list;
                if (rightBinary != null && rightBinary.OperatorToken == JsToken.Comma)
                {
                    // the right is ALSO a comma operator. Create a new list, append all the rest of the operands
                    // and set our right-hand side to be the list
                    list = new JsAstNodeList(null, parser);
                    list.Append(leftBinary.Operand2).Append(rightBinary.Operand1).Append(rightBinary.Operand2);
                }
                else
                {
                    // the right is not a comma operator.
                    // see if the left-hand side already has a list we can use
                    list = leftBinary.Operand2 as JsAstNodeList;
                    if (list == null)
                    {
                        // it's not a list already
                        // create a new list with the left's right and our right and set it to our right
                        list = new JsAstNodeList(null, parser);
                        list.Append(leftBinary.Operand2);
                    }

                    // and add our right-hand operand to the end of the list
                    list.Append(operand2);
                }

                // set the list on the right
                comma.Operand2 = list;
            }
            else if (rightBinary != null && rightBinary.OperatorToken == JsToken.Comma)
            {
                // the left hand side is NOT a comma operator.
                comma.Operand1 = operand1;

                // the right-hand side is already a comma-operator, but the left is not.
                // see if it already has a list we can reuse
                var rightList = rightBinary.Operand2 as JsAstNodeList;
                if (rightList != null)
                {
                    // it does. Prepend its right-hand operand and use the list
                    rightList.Insert(0, rightBinary.Operand1);
                }
                else
                {
                    // it's not -- create a new list containing the operands
                    rightList = new JsAstNodeList(rightBinary.Context, parser);
                    rightList.Append(rightBinary.Operand1);
                    rightList.Append(rightBinary.Operand2);
                }

                comma.Operand2 = rightList;
            }
            else
            {
                comma.Operand1 = operand1;
                comma.Operand2 = operand2;
            }

            return(comma);
        }
        private static JsAstNode CreateSplitNodeFromEnd(JsAstNodeList nodeList, int ndx)
        {
            JsAstNode newNode;
            if (ndx == nodeList.Count - 1)
            {
                // the LAST one can be broken. Pull it off the list and we will just
                // insert it after the current node.
                newNode = nodeList[ndx];
                nodeList.RemoveAt(ndx);
            }
            else if (ndx == nodeList.Count - 2)
            {
                // the PENULTIMATE item can be broken. So create a new comma operator
                // with the just the last two item and we'll insert it after the current node
                var left = nodeList[ndx];
                nodeList.RemoveAt(ndx);
                var right = nodeList[ndx];
                nodeList.RemoveAt(ndx);

                newNode = new JsCommaOperator(null, nodeList.Parser)
                    {
                        Operand1 = left,
                        Operand2 = right
                    };
            }
            else
            {
                // at least three items will be pulled off, which means there will
                // be at least two items on the right, so we'll create a new astlist to
                // insert those items into a new comma operator
                var left = nodeList[ndx];
                nodeList.RemoveAt(ndx);

                // if we were passed zero, then just reuse the node list.
                // otherwise we need to create a new one and move the items
                // from the index position over.
                JsAstNodeList right;
                if (ndx == 0)
                {
                    right = nodeList;
                }
                else
                {
                    right = new JsAstNodeList(null, nodeList.Parser);
                    while (ndx < nodeList.Count)
                    {
                        var temp = nodeList[ndx];
                        nodeList.RemoveAt(ndx);
                        right.Append(temp);
                    }
                }

                newNode = new JsCommaOperator(null, nodeList.Parser)
                    {
                        Operand1 = left,
                        Operand2 = right
                    };
            }

            return newNode;
        }
        private static JsAstNode CreateSplitNodeFromEnd(JsAstNodeList nodeList, int ndx)
        {
            JsAstNode newNode;

            if (ndx == nodeList.Count - 1)
            {
                // the LAST one can be broken. Pull it off the list and we will just
                // insert it after the current node.
                newNode = nodeList[ndx];
                nodeList.RemoveAt(ndx);
            }
            else if (ndx == nodeList.Count - 2)
            {
                // the PENULTIMATE item can be broken. So create a new comma operator
                // with the just the last two item and we'll insert it after the current node
                var left = nodeList[ndx];
                nodeList.RemoveAt(ndx);
                var right = nodeList[ndx];
                nodeList.RemoveAt(ndx);

                newNode = new JsCommaOperator(null, nodeList.Parser)
                {
                    Operand1 = left,
                    Operand2 = right
                };
            }
            else
            {
                // at least three items will be pulled off, which means there will
                // be at least two items on the right, so we'll create a new astlist to
                // insert those items into a new comma operator
                var left = nodeList[ndx];
                nodeList.RemoveAt(ndx);

                // if we were passed zero, then just reuse the node list.
                // otherwise we need to create a new one and move the items
                // from the index position over.
                JsAstNodeList right;
                if (ndx == 0)
                {
                    right = nodeList;
                }
                else
                {
                    right = new JsAstNodeList(null, nodeList.Parser);
                    while (ndx < nodeList.Count)
                    {
                        var temp = nodeList[ndx];
                        nodeList.RemoveAt(ndx);
                        right.Append(temp);
                    }
                }

                newNode = new JsCommaOperator(null, nodeList.Parser)
                {
                    Operand1 = left,
                    Operand2 = right
                };
            }

            return(newNode);
        }