Of the 244 functions supported by our upcoming release, 242 are intended to be compatible with spreadsheets and two are specific to Calcapp: ISDEFINED and BLANK.
ISDEFINED returns whether a value is defined. The formula
ISDEFINED(Field1) is exactly equivalent to
NOT(ISBLANK(Field1)). We find it
convenient to be able to write formulas like
10) (which returns the value of Field1 if it is defined and 10 otherwise).
BLANK returns a blank value. For instance, you can hide an error value (such
as division by zero) using this formula:
Spreadsheets generally do not provide a way to reset a cell value to its
initial, blank state. As a result, spreadsheet users tend to use the empty
string (“”) instead. (This causes all sorts of problems, as ISBLANK when applied
to the empty string returns FALSE.)
In Calcapp, you can only assign the empty string to a field if the field is a text field. If the field is a number field or a logical field, you will get an error message. Calcapp is more strict than most spreadsheets in this respect: if a field is defined to be a number field, only numbers can be assigned to it, if it is defined to be a logical field, only logical values can be assigned to it and finally, if it is defined to be a text field, only text strings can be assigned to it. (This is known as static typing.) The return value of the BLANK function, however, can be assigned to any field. Thus, while the BLANK function would be a great addition to spreadsheets like Microsoft Excel, it’s actually even more essential for Calcapp.