/// <summary>
/// Reads an arithmetic 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 unit.</param>
/// <param name="unsafeCode">Indicates whether the code being parsed resides in an unsafe code block.</param>
/// <returns>Returns the expression.</returns>
private ArithmeticExpression GetArithmeticExpression(
Expression leftHandSide, ExpressionPrecedence previousPrecedence, Reference<ICodePart> parentReference, bool unsafeCode)
{
Param.AssertNotNull(leftHandSide, "leftHandSide");
Param.Ignore(previousPrecedence);
Param.AssertNotNull(parentReference, "parentReference");
Param.Ignore(unsafeCode);
ArithmeticExpression expression = null;
var expressionReference = new Reference<ICodePart>();
// Read the details of the expression.
OperatorSymbol operatorToken = this.PeekOperatorToken(parentReference, expressionReference);
Debug.Assert(
operatorToken.Category == OperatorCategory.Arithmetic || operatorToken.Category == OperatorCategory.Shift,
"Expected an arithmetic or shift 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(precedence, 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.
ArithmeticExpression.Operator type;
switch (operatorToken.SymbolType)
{
case OperatorType.Plus:
type = ArithmeticExpression.Operator.Addition;
break;
case OperatorType.Minus:
type = ArithmeticExpression.Operator.Subtraction;
break;
case OperatorType.Multiplication:
type = ArithmeticExpression.Operator.Multiplication;
break;
case OperatorType.Division:
type = ArithmeticExpression.Operator.Division;
break;
case OperatorType.Mod:
type = ArithmeticExpression.Operator.Mod;
break;
case OperatorType.LeftShift:
type = ArithmeticExpression.Operator.LeftShift;
break;
case OperatorType.RightShift:
type = ArithmeticExpression.Operator.RightShift;
break;
default:
Debug.Fail("Unexpected operator type");
throw new InvalidOperationException();
}
// Create and return the expression.
expression = new ArithmeticExpression(partialTokens, type, leftHandSide, rightHandSide);
expressionReference.Target = expression;
}
return expression;
}
private bool CheckArithmeticParenthesisForExpressionAndChild(CsElement element, ArithmeticExpression expression, ArithmeticExpression childExpression)
{
if ((expression.OperatorType != childExpression.OperatorType) && (((((expression.OperatorType != ArithmeticExpression.Operator.Addition) && (expression.OperatorType != ArithmeticExpression.Operator.Subtraction)) || ((childExpression.OperatorType != ArithmeticExpression.Operator.Addition) && (childExpression.OperatorType != ArithmeticExpression.Operator.Subtraction))) && (((expression.OperatorType != ArithmeticExpression.Operator.Multiplication) && (expression.OperatorType != ArithmeticExpression.Operator.Division)) || ((childExpression.OperatorType != ArithmeticExpression.Operator.Multiplication) && (childExpression.OperatorType != ArithmeticExpression.Operator.Division)))) && (((expression.OperatorType != ArithmeticExpression.Operator.LeftShift) && (expression.OperatorType != ArithmeticExpression.Operator.RightShift)) || ((childExpression.OperatorType != ArithmeticExpression.Operator.LeftShift) && (childExpression.OperatorType != ArithmeticExpression.Operator.RightShift)))))
{
base.AddViolation(element, expression.LineNumber, Microsoft.StyleCop.CSharp.Rules.ArithmeticExpressionsMustDeclarePrecedence, new object[0]);
return false;
}
return true;
}
/// <summary>
/// Checks whether parenthesis are needed within the arithmetic expressions.
/// </summary>
/// <param name="element">The parent element.</param>
/// <param name="expression">The parent arithmetic expression.</param>
/// <param name="childExpression">The child arithmetic expression.</param>
/// <returns>Returns true if there is no violation, or false if there is a violation.</returns>
private bool CheckArithmeticParenthesisForExpressionAndChild(
CsElement element, ArithmeticExpression expression, ArithmeticExpression childExpression)
{
Param.AssertNotNull(element, "element");
Param.AssertNotNull(expression, "expression");
Param.AssertNotNull(childExpression, "childExpression");
// Parenthesis are only required when the two expressions are not the same operator,
// and when the two operators come from different families.
if (expression.OperatorType != childExpression.OperatorType)
{
bool sameFamily =
((expression.OperatorType == ArithmeticExpression.Operator.Addition ||
expression.OperatorType == ArithmeticExpression.Operator.Subtraction) &&
(childExpression.OperatorType == ArithmeticExpression.Operator.Addition ||
childExpression.OperatorType == ArithmeticExpression.Operator.Subtraction)) ||
((expression.OperatorType == ArithmeticExpression.Operator.Multiplication ||
expression.OperatorType == ArithmeticExpression.Operator.Division) &&
(childExpression.OperatorType == ArithmeticExpression.Operator.Multiplication ||
childExpression.OperatorType == ArithmeticExpression.Operator.Division)) ||
((expression.OperatorType == ArithmeticExpression.Operator.LeftShift ||
expression.OperatorType == ArithmeticExpression.Operator.RightShift) &&
(childExpression.OperatorType == ArithmeticExpression.Operator.LeftShift ||
childExpression.OperatorType == ArithmeticExpression.Operator.RightShift));
if (!sameFamily)
{
this.AddViolation(element, expression.LineNumber, Rules.ArithmeticExpressionsMustDeclarePrecedence);
return false;
}
}
return true;
}
private void CheckArithmeticExpressionParenthesis(CsElement element, ArithmeticExpression expression)
{
if (((expression.LeftHandSide.ExpressionType != ExpressionType.Arithmetic) || this.CheckArithmeticParenthesisForExpressionAndChild(element, expression, (ArithmeticExpression) expression.LeftHandSide)) && (expression.RightHandSide.ExpressionType == ExpressionType.Arithmetic))
{
this.CheckArithmeticParenthesisForExpressionAndChild(element, expression, (ArithmeticExpression) expression.RightHandSide);
}
}
/// <summary>
/// Checks that parenthesis are used correctly within an arithmetic expression.
/// </summary>
/// <param name="element">The parent element.</param>
/// <param name="expression">The expression to check.</param>
private void CheckArithmeticExpressionParenthesis(CsElement element, ArithmeticExpression expression)
{
Param.AssertNotNull(element, "element");
Param.AssertNotNull(expression, "expression");
if (expression.LeftHandSide.ExpressionType == ExpressionType.Arithmetic)
{
if (!this.CheckArithmeticParenthesisForExpressionAndChild(
element, expression, (ArithmeticExpression)expression.LeftHandSide))
{
return;
}
}
if (expression.RightHandSide.ExpressionType == ExpressionType.Arithmetic)
{
this.CheckArithmeticParenthesisForExpressionAndChild(
element, expression, (ArithmeticExpression)expression.RightHandSide);
}
}