/**
* 将切分的元素转化成ExpressionToken，并验证减号还是负号
* @param previousToken
* @param ele
* @return
* @throws ParseException
*/
public ExpressionToken ChangeToToken(ExpressionToken previousToken, Element ele)
{
if (ele == null)
{
throw new ArgumentException();
}
ExpressionToken token = null;
//转成ExpressionToken
if (ElementType.NULL == ele.Type)
{
token = ExpressionToken.CreateConstantToken(DataType.DATATYPE_NULL, null);
}
else if (ElementType.STRING == ele.Type)
{
token = ExpressionToken.CreateConstantToken(DataType.DATATYPE_STRING, ele.Text);
}
else if (ElementType.BOOLEAN == ele.Type)
{
token = ExpressionToken.CreateConstantToken(DataType.DATATYPE_BOOLEAN, Convert.ToBoolean(ele.Text));
}
else if (ElementType.INT == ele.Type)
{
token = ExpressionToken.CreateConstantToken(DataType.DATATYPE_INT, Convert.ToInt32(ele.Text));
}
else if (ElementType.LONG == ele.Type)
{
token = ExpressionToken.CreateConstantToken(DataType.DATATYPE_LONG, Convert.ToInt64(ele.Text));
}
else if (ElementType.FLOAT == ele.Type)
{
token = ExpressionToken.CreateConstantToken(DataType.DATATYPE_FLOAT, Convert.ToSingle(ele.Text));
}
else if (ElementType.DOUBLE == ele.Type)
{
token = ExpressionToken.CreateConstantToken(DataType.DATATYPE_DOUBLE, Convert.ToDouble(ele.Text));
}
else if (ElementType.DATE == ele.Type)
{
token = ExpressionToken.CreateConstantToken(DataType.DATATYPE_DATE, Convert.ToDateTime(ele.Text));
}
else if (ElementType.VARIABLE == ele.Type)
{
token = ExpressionToken.CreateVariableToken(ele.Text);
}
else if (ElementType.OPERATOR == ele.Type)
{
//区分负号
if (ele.Text.Equals("-") && (
previousToken == null || //以“-”开头肯定是负号
previousToken.TokenType == ETokenType.ETOKEN_TYPE_OPERATOR || //运算符后面肯定是负号
previousToken.TokenType == ETokenType.ETOKEN_TYPE_SPLITOR && //“(”或“,”后面肯定是负号
!")".Equals(previousToken.GetSplitor())
))
{
token = ExpressionToken.CreateOperatorToken(Operator.NG);
}
else
{
token = ExpressionToken.CreateOperatorToken(GetOperator(ele.Text));
}
}
else if (ElementType.FUNCTION == ele.Type)
{
token = ExpressionToken.CreateFunctionToken(ele.Text);
}
else if (ElementType.SPLITOR == ele.Type)
{
token = ExpressionToken.CreateSplitorToken(ele.Text);
}
token.StartPosition = ele.Index;
return(token);
}