Evaluates a FormCalcSpec against the current field values. Blank or
unparseable operands are skipped (a SUM of no operands is 0; the other
operations return null when there is nothing to combine, leaving the field
unchanged). Returns the computed value as a plain number string, or null.
Evaluates a FormCalcSpec against the current field values. Blank or unparseable operands are skipped (a
SUMof no operands is0; the other operations returnnullwhen there is nothing to combine, leaving the field unchanged). Returns the computed value as a plain number string, ornull.