Formatting the cells in NSTableView

[Vikram Vyas]

Hello,

I am porting an application for designing and simulating rainwater harvesting system (http://homepage.mac.com/vsvyas/science.html#simtanka) from Visual Basic to GNUstep.

I have a table in which the user enters monthly rainfall data using

- (void) tableView: (NSTableView *) view
setObjectValue: (id) object
forTableColumn: (NSTableColumn *) column
row: (int) row
I  would like that user should be able to enter only positive numbers in  monthly rainfall columns, and a year greater than 1900 in the year column. Would appreciate any help on this.

Thanks,
Vikram