My Excel spreadsheet contains a Date in column A and the following formula in column B.
```
=IF([@IssueDate]<>"",TODAY()-[@IssueDate],"")
```
When the 'Compute' method is called, the result '#VALUE!' is assigned to column B rather than the proper value.
The error appears to be occurring because the not equal operator "<>" is not recognized by the parser. The problem appears to be in method 'Init' at line 49 in file 'TokenSeparatorProvider.cs'. It does not include token "<>" in the '_tokens' dictionary. In addition, method 'IsPossibleLastPartOfMultipleCharOperator' may need to be updated to say "return (part == "=" || part == ">");".
There is a second issue regarding Date values in arithmetic expressions that prevents the expression from begin evaluated correctly. I will submit that issue in a separate bug report.
I have attached a simple spread sheet that reproduces this problem.
```
=IF([@IssueDate]<>"",TODAY()-[@IssueDate],"")
```
When the 'Compute' method is called, the result '#VALUE!' is assigned to column B rather than the proper value.
The error appears to be occurring because the not equal operator "<>" is not recognized by the parser. The problem appears to be in method 'Init' at line 49 in file 'TokenSeparatorProvider.cs'. It does not include token "<>" in the '_tokens' dictionary. In addition, method 'IsPossibleLastPartOfMultipleCharOperator' may need to be updated to say "return (part == "=" || part == ">");".
There is a second issue regarding Date values in arithmetic expressions that prevents the expression from begin evaluated correctly. I will submit that issue in a separate bug report.
I have attached a simple spread sheet that reproduces this problem.