/// <summary>
/// Reads a null condition expression from the code.
/// </summary>
/// <param name="leftHandSide">The left hand side.</param>
/// <param name="previousPrecedence">The previous precedence.</param>
/// <param name="parentReference">The parent code unit.</param>
/// <param name="unsafeCode">Indicates whether the code being parsed resides in an unsafe code block.</param>
/// <returns>
/// Returns the expression.
/// </returns>
private Expression GetNullConditionExpression(
Expression leftHandSide, ExpressionPrecedence previousPrecedence, Reference<ICodePart> parentReference, bool unsafeCode)
{
Param.AssertNotNull(leftHandSide, "leftHandSide");
Param.Ignore(previousPrecedence);
Param.AssertNotNull(parentReference, "parentReference");
Param.Ignore(unsafeCode);
NullConditionExpression expression = null;
Reference<ICodePart> expressionReference = new Reference<ICodePart>();
// Read the details of the expression.
OperatorSymbol operatorToken = this.PeekOperatorToken(parentReference, expressionReference);
Debug.Assert(operatorToken.SymbolType == OperatorType.NullConditional, "Expected a null-conditional symbol");
// 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);
Expression rightHandSide = null;
Symbol nextSymbol = this.symbols.Peek(1);
// Check if next symbol is an open square bracket.
if (nextSymbol.SymbolType == SymbolType.OpenSquareBracket)
{
rightHandSide = this.GetArrayAccessExpression(leftHandSide, previousPrecedence, unsafeCode);
}
else
{
rightHandSide = this.GetOperatorRightHandExpression(precedence, expressionReference, unsafeCode);
}
// We must find an expression else there is a syntax exception.
if (rightHandSide == null)
{
this.CreateSyntaxException();
}
// Create the partial token list for the expression.
CsTokenList partialTokens = new CsTokenList(this.tokens, leftHandSide.Tokens.First, this.tokens.Last);
// Create and return the expression.
expression = new NullConditionExpression(partialTokens, leftHandSide, rightHandSide);
expressionReference.Target = expression;
}
return expression;
}
/// <summary>
/// Reads a null condition expression from the code.
/// </summary>
/// <param name="leftHandSide">The left hand side.</param>
/// <param name="previousPrecedence">The previous precedence.</param>
/// <param name="parentReference">The parent code unit.</param>
/// <param name="unsafeCode">Indicates whether the code being parsed resides in an unsafe code block.</param>
/// <returns>
/// Returns the expression.
/// </returns>
private Expression GetNullConditionExpression(
Expression leftHandSide, ExpressionPrecedence previousPrecedence, Reference<ICodePart> parentReference, bool unsafeCode)
{
Param.AssertNotNull(leftHandSide, "leftHandSide");
Param.Ignore(previousPrecedence);
Param.AssertNotNull(parentReference, "parentReference");
Param.Ignore(unsafeCode);
NullConditionExpression expression = null;
Reference<ICodePart> expressionReference = new Reference<ICodePart>();
// Read the details of the expression.
OperatorSymbol operatorToken = this.PeekOperatorToken(parentReference, expressionReference);
Debug.Assert(operatorToken.SymbolType == OperatorType.NullConditional, "Expected a null-conditional symbol");
// 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(precedence, expressionReference, unsafeCode);
// Create the partial token list for the expression.
CsTokenList partialTokens = new CsTokenList(this.tokens, leftHandSide.Tokens.First, this.tokens.Last);
// Create and return the expression.
expression = new NullConditionExpression(partialTokens, leftHandSide, rightHandSide);
expressionReference.Target = expression;
}
return expression;
}
