/// <summary>
/// Determine whether parentheses are needed around the right subtree base on the current operator.
/// </summary>
/// <param name="currentOperator">The current binary node's operator.</param>
/// <param name="rightSubtree">The right binary subtree.</param>
/// <returns>True if need parentheses, false if not.</returns>
private static bool NeedParenthesesRight(BinaryOperator currentOperator, BinaryOperatorQueryToken rightSubtree)
{
BinaryOperator rightOperator = BinaryOperator.GetOperator(rightSubtree.OperatorKind);
if (currentOperator.Precedence < rightOperator.Precedence)
{
return(false);
}
if (currentOperator.Precedence > rightOperator.Precedence)
{
return(true);
}
// They are equal in precedence,
return(currentOperator.NeedParenEvenWhenTheSame);
}
private void Write(bool needParenthesis, BinaryOperatorQueryToken binary)
{
if (needParenthesis)
{
this.builder.Append(ExpressionConstants.SymbolOpenParen);
}
BinaryOperator currentOperator = BinaryOperator.GetOperator(binary.OperatorKind);
// Left binary expression may need paren depending on their operator
BinaryOperatorQueryToken leftBinaryExpr = binary.Left as BinaryOperatorQueryToken;
if (leftBinaryExpr != null)
{
Write(NeedParenthesesLeft(currentOperator, leftBinaryExpr), leftBinaryExpr);
}
else
{
this.builder.WriteQuery(binary.Left);
}
this.builder.Append(ExpressionConstants.SymbolEscapedSpace);
this.builder.Append(currentOperator.Text);
this.builder.Append(ExpressionConstants.SymbolEscapedSpace);
// Right binary expression may need paren depending on their operator
BinaryOperatorQueryToken rightBinaryExpr = binary.Right as BinaryOperatorQueryToken;
if (rightBinaryExpr != null)
{
Write(NeedParenthesesRight(currentOperator, rightBinaryExpr), rightBinaryExpr);
}
else
{
this.builder.WriteQuery(binary.Right);
}
if (needParenthesis)
{
this.builder.Append(ExpressionConstants.SymbolClosedParen);
}
}
/// <summary>
/// Determine whether parentheses are needed around the left subtree base on the current operator.
/// </summary>
/// <param name="currentOperator">The current binary node's operator.</param>
/// <param name="leftSubtree">The left binary subtree.</param>
/// <returns>True if need parenthese, false if not.</returns>
private static bool NeedParenthesesLeft(BinaryOperator currentOperator, BinaryOperatorQueryToken leftSubtree)
{
BinaryOperator leftOperator = BinaryOperator.GetOperator(leftSubtree.OperatorKind);
return(leftOperator.Precedence < currentOperator.Precedence);
}