excel_functions.rb in rubyfromexcel-0.0.9

- old
+ new

@@ -132,10 +132,14 @@
       return divisor if iserr(divisor)
       return :na unless number.is_a?(Numeric)
       return :na unless divisor.is_a?(Numeric)
       number % divisor
     end
+    
+    def pmt(rate,periods,principal)
+      -principal*(rate*((1+rate)**periods))/(((1+rate)**periods)-1)
+    end
             
     def sum(*args)
       flatten_and_inject(args) do |counter,arg|
         arg.is_a?(Numeric) ? counter + arg.to_f : counter
       end
@@ -206,13 +210,15 @@
     end
   
     def max(*args)
       args = args.map { |arg| arg.respond_to?(:to_a) ? arg.to_a : arg }
       args.flatten!
+      if (error = args.find { |arg| iserr(arg) }) 
+        return error
+      end
       args.delete_if { |arg| !arg.kind_of?(Numeric) }
       args.delete_if { |arg| arg.kind_of?(Empty) }
-      return error if error = args.find { |arg| iserr(arg) }
       args.max
     end
   
     def abs(value)
       return value if iserr(value)
@@ -342,14 +348,15 @@
       :ref
     end
   
     def iserr(arg)
       return true if arg.is_a? Symbol
-      return true if arg.is_a?(Float) && arg.nan?
+      return true if arg.respond_to?(:nan?) && arg.nan?
+      return true if arg.respond_to?(:infinite?) && arg.infinite?
       false
     end
   
-    def excel_if(condition,true_value,false_value)
+    def excel_if(condition,true_value,false_value = false)
       condition ? true_value : false_value
     end
   
     def iferror(value,value_if_error)
       iserr(value) ? value_if_error : value
\ No newline at end of file