Just came cross an issue lately with SharePoint 2010 field (Column) formulas.
The issues is when I was applying formulas on Arabic culture sites, SharePoint kept giving me errors parsing the formula.
I have 2 fields [Start Date] and [End Date]
To calculate the days between the two dates and display “-” if the [End Date] is empty, you can use something like:
=IF(ISBLANK([End Date]),”-“,DATEDIF([End Date],[Start Date],”d”))
This will calculate the days between the two dates only if the [End Date] is blank and works perfectly in English based sites.
If you want to do the same in Arabic Language sites (Even if the column names in English), simple you need to replace the comma “,” with semi column “;”, the result will be something this:
As stated in this MSDN article, this must be done for specific languages/cultures and if the website culture changed back again to English, the formula will be changed automatically to use the comma model (Didn’t test this).
I hope that helped