// ExprAddSub: PlusMinusOperator Term ExprRhs
private void MatchExprAddSub(out IExpr result)
{
TokenTypes t; // remember the type
IExpr lhs;
MatchExprMultDiv(out lhs);
result = lhs; // in case we get no matches
while ((t = curToken.Type) == TokenTypes.PLUS || t == TokenTypes.PLUSSTRING || t == TokenTypes.MINUS)
{
curToken = tokens.Extract();
IExpr rhs;
MatchExprMultDiv(out rhs);
TypeCode lt = lhs.GetTypeCode();
TypeCode rt = rhs.GetTypeCode();
bool bDecimal = (rt == TypeCode.Decimal &&
lt == TypeCode.Decimal);
bool bInt32 = (rt == TypeCode.Int32 &&
lt == TypeCode.Int32);
bool bString = (rt == TypeCode.String ||
lt == TypeCode.String);
switch(t)
{
case TokenTypes.PLUSSTRING:
result = new FunctionPlusString(lhs, rhs);
break;
case TokenTypes.PLUS:
if (bDecimal)
result = new FunctionPlusDecimal(lhs, rhs);
else if (bString)
result = new FunctionPlusString(lhs, rhs);
else if (bInt32)
result = new FunctionPlusInt32(lhs, rhs);
else
result = new FunctionPlus(lhs, rhs);
break;
case TokenTypes.MINUS:
if (bDecimal)
result = new FunctionMinusDecimal(lhs, rhs);
else if (bString)
throw new ParserException("'-' operator works only on numbers." + " At column " + Convert.ToString(curToken.StartCol));
else if (bInt32)
result = new FunctionMinusInt32(lhs, rhs);
else
result = new FunctionMinus(lhs, rhs);
break;
}
lhs = result; // in case continue in the loop
}
}
// ExprAddSub: PlusMinusOperator Term ExprRhs
private void MatchExprAddSub(out IExpr result)
{
TokenTypes t; // remember the type
IExpr lhs;
MatchExprMultDiv(out lhs);
result = lhs; // in case we get no matches
while ((t = curToken.Type) == TokenTypes.PLUS || t == TokenTypes.PLUSSTRING || t == TokenTypes.MINUS)
{
curToken = tokens.Extract();
IExpr rhs;
MatchExprMultDiv(out rhs);
TypeCode lt = lhs.GetTypeCode();
TypeCode rt = rhs.GetTypeCode();
bool bDecimal = (rt == TypeCode.Decimal &&
lt == TypeCode.Decimal);
bool bInt32 = (rt == TypeCode.Int32 &&
lt == TypeCode.Int32);
bool bString = (rt == TypeCode.String ||
lt == TypeCode.String);
switch(t)
{
case TokenTypes.PLUSSTRING:
result = new FunctionPlusString(lhs, rhs);
break;
case TokenTypes.PLUS:
if (bDecimal)
result = new FunctionPlusDecimal(lhs, rhs);
else if (bString)
result = new FunctionPlusString(lhs, rhs);
else if (bInt32)
result = new FunctionPlusInt32(lhs, rhs);
else
result = new FunctionPlus(lhs, rhs);
break;
case TokenTypes.MINUS:
if (bDecimal)
result = new FunctionMinusDecimal(lhs, rhs);
else if (bString)
throw new ParserException(Strings.Parser_ErrorP_MinusNeedNumbers + GetLocationInfo(curToken));
else if (bInt32)
result = new FunctionMinusInt32(lhs, rhs);
else
result = new FunctionMinus(lhs, rhs);
break;
}
lhs = result; // in case continue in the loop
}
}