/// <summary>
/// Reads an assignment expression.
/// </summary>
/// <param name="leftHandSide">The expression on the left hand side of the operator.</param>
/// <param name="previousPrecedence">The precedence of the expression just before this one.</param>
/// <param name="parentReference">The parent code part.</param>
/// <param name="unsafeCode">Indicates whether the code being parsed resides in an unsafe code block.</param>
/// <returns>Returns the expression.</returns>
private AssignmentExpression GetAssignmentExpression(
Expression leftHandSide, ExpressionPrecedence previousPrecedence, Reference<ICodePart> parentReference, bool unsafeCode)
{
Param.AssertNotNull(leftHandSide, "leftHandSide");
Param.Ignore(previousPrecedence);
Param.Ignore(parentReference, "parentReference");
Param.Ignore(unsafeCode);
AssignmentExpression expression = null;
var expressionReference = new Reference<ICodePart>();
// Read the details of the expression.
OperatorSymbol operatorToken = this.PeekOperatorToken(parentReference, expressionReference);
Debug.Assert(operatorToken.Category == OperatorCategory.Assignment, "Expected an assignment operator");
// Check the precedence of the operators to make sure we can gather this statement now.
ExpressionPrecedence precedence = GetOperatorPrecedence(operatorToken.SymbolType);
if (CheckPrecedence(previousPrecedence, precedence))
{
// Add the operator token to the document and advance the symbol manager up to it.
this.symbols.Advance();
this.tokens.Add(operatorToken);
// Get the expression on the right-hand side of the operator.
Expression rightHandSide = this.GetOperatorRightHandExpression(ExpressionPrecedence.None, expressionReference, unsafeCode);
// Create the partial token list for the expression.
CsTokenList partialTokens = new CsTokenList(this.tokens, leftHandSide.Tokens.First, this.tokens.Last);
// Get the expression operator type.
AssignmentExpression.Operator type;
switch (operatorToken.SymbolType)
{
case OperatorType.Equals:
type = AssignmentExpression.Operator.Equals;
break;
case OperatorType.PlusEquals:
type = AssignmentExpression.Operator.PlusEquals;
break;
case OperatorType.MinusEquals:
type = AssignmentExpression.Operator.MinusEquals;
break;
case OperatorType.MultiplicationEquals:
type = AssignmentExpression.Operator.MultiplicationEquals;
break;
case OperatorType.DivisionEquals:
type = AssignmentExpression.Operator.DivisionEquals;
break;
case OperatorType.AndEquals:
type = AssignmentExpression.Operator.AndEquals;
break;
case OperatorType.OrEquals:
type = AssignmentExpression.Operator.OrEquals;
break;
case OperatorType.XorEquals:
type = AssignmentExpression.Operator.XorEquals;
break;
case OperatorType.ModEquals:
type = AssignmentExpression.Operator.ModEquals;
break;
case OperatorType.LeftShiftEquals:
type = AssignmentExpression.Operator.LeftShiftEquals;
break;
case OperatorType.RightShiftEquals:
type = AssignmentExpression.Operator.RightShiftEquals;
break;
default:
Debug.Fail("Unexpected operator type");
throw new InvalidOperationException();
}
// Create and return the expression.
expression = new AssignmentExpression(partialTokens, type, leftHandSide, rightHandSide);
expressionReference.Target = expression;
}
return expression;
}
/// <summary>
/// Gets an object initializer expression.
/// </summary>
/// <param name="unsafeCode">Indicates whether the code being parsed resides in an unsafe code block.</param>
/// <returns>Returns the expression.</returns>
private ObjectInitializerExpression GetObjectInitializerExpression(bool unsafeCode)
{
Param.Ignore(unsafeCode);
var expressionReference = new Reference<ICodePart>();
List<AssignmentExpression> initializerExpressions = new List<AssignmentExpression>();
// Add and move past the opening curly bracket.
Bracket openingBracket = this.GetBracketToken(CsTokenType.OpenCurlyBracket, SymbolType.OpenCurlyBracket, expressionReference);
Node<CsToken> openingBracketNode = this.tokens.InsertLast(openingBracket);
while (true)
{
// If the next symbol is the closing curly bracket, then we are done.
Symbol symbol = this.GetNextSymbol(expressionReference);
if (symbol.SymbolType == SymbolType.CloseCurlyBracket)
{
break;
}
var initializerExpressionReference = new Reference<ICodePart>();
// Get the identifier.
LiteralExpression identifier = this.GetLiteralExpression(initializerExpressionReference, unsafeCode);
// Get the equals sign.
symbol = this.GetNextSymbol(initializerExpressionReference);
if (symbol.SymbolType != SymbolType.Equals)
{
throw this.CreateSyntaxException();
}
this.tokens.Add(this.GetOperatorToken(OperatorType.Equals, initializerExpressionReference));
// Get the initializer value. If this begins with an opening curly bracket,
// this is an embedded object or collection initializer. Otherwise, it is
// some other kind of expression.
Expression initializerValue = null;
symbol = this.GetNextSymbol(initializerExpressionReference);
if (symbol.SymbolType == SymbolType.OpenCurlyBracket)
{
initializerValue = this.GetObjectOrCollectionInitializerExpression(initializerExpressionReference, unsafeCode);
}
else
{
initializerValue = this.GetNextExpression(ExpressionPrecedence.None, initializerExpressionReference, unsafeCode);
}
// Create and add this initializer.
CsTokenList initializerTokens = new CsTokenList(this.tokens, identifier.Tokens.First, initializerValue.Tokens.Last);
var initializerExpression = new AssignmentExpression(
initializerTokens, AssignmentExpression.Operator.Equals, identifier, initializerValue);
initializerExpressionReference.Target = initializerExpression;
initializerExpressions.Add(initializerExpression);
// Check whether we're done.
symbol = this.GetNextSymbol(expressionReference);
if (symbol.SymbolType == SymbolType.Comma)
{
this.tokens.Add(this.GetToken(CsTokenType.Comma, SymbolType.Comma, expressionReference));
// If the next symbol after this is the closing curly bracket, then we are done.
symbol = this.GetNextSymbol(expressionReference);
if (symbol.SymbolType == SymbolType.CloseCurlyBracket)
{
break;
}
}
else
{
break;
}
}
// Add and move past the closing curly bracket.
Bracket closingBracket = this.GetBracketToken(CsTokenType.CloseCurlyBracket, SymbolType.CloseCurlyBracket, expressionReference);
Node<CsToken> closingBracketNode = this.tokens.InsertLast(closingBracket);
openingBracket.MatchingBracketNode = closingBracketNode;
closingBracket.MatchingBracketNode = openingBracketNode;
// Create the token list for the overall expression.
CsTokenList expressionTokens = new CsTokenList(this.tokens, openingBracketNode, closingBracketNode);
// Create and return the expression.
var expression = new ObjectInitializerExpression(expressionTokens, initializerExpressions.ToArray());
expressionReference.Target = expression;
return expression;
}
