excel_functions.rb in rubyfromexcel-0.0.16

- old
+ new

@@ -102,10 +102,17 @@
       worksheet.instance_variable_set("@formula_cache",formula_cache)
       @worksheets[worksheet_name] = worksheet
       worksheet
     end
     
+    def text(number,format)
+      return number if iserr(number)
+      return format if iserr(format)
+      raise Exception.new("format #{format} not implemented") unless format.is_a?(Numeric)
+      number.round(format).to_s
+    end
+    
     def round(number,decimal_places)
       return number if iserr(number)
       return decimal_places if iserr(decimal_places)
       return :na unless number.is_a?(Numeric)
       return :na unless decimal_places.is_a?(Numeric)
@@ -135,9 +142,10 @@
       return :na unless divisor.is_a?(Numeric)
       number % divisor
     end
     
     def pmt(rate,periods,principal)
+      return -(principal / periods) if rate == 0
       -principal*(rate*((1+rate)**periods))/(((1+rate)**periods)-1)
     end
     
     def npv(rate,*cashflows)
       discount_factor = 1
\ No newline at end of file