Converting Hexadecimal, Decimal, Octal, and ASCII?

Question

Trying to and from bases in Ruby... the code I've laid out seems quite repetitious. Is ther a better way?

module Converter   def self.convert(value, from, to)     case from     when :hex       case to       when :dec         # code to change hex to dec       when :oct         # code to change hex to oct       when :bin         # code to change hex to bin       when :ascii         # code to change hex to ascii       end     when :dec       case to       when :hex         # code to change dec to hex       when :oct         # code to change dec to oct       when :bin         # code to change dec to bin       when :ascii         # code to change dec to ascii       end     when :oct       case to       when :hex         # code to change oct to hex       when :dec         # code to change oct to dec       when :bin         # code to change oct to bin       when :ascii         # code to change oct to ascii       end     when :bin       case to       when :hex         # code to change bin to hex       when :dec         # code to change bin to dec       when :oct         # code to change bin to oct       when :ascii         # code to change bin to ascii       end     when :ascii       case to       when :hex         # code to change ascii to hex       when :dec         # code to change ascii to dec       when :oct         # code to change ascii to oct       when :bin         # code to change ascii to bin       end     end   end end 

Answer 1

class String   def convert_base(from, to)     self.to_i(from).to_s(to)     # works up-to base 36   end end  p '1010'.convert_base(2, 10) #=> "10" p 'FF'.convert_base(16, 2)   #=> "11111111" 

Answer 2

Come up with code to convert from anything to decimal and from decimal to anything and then combine those. E.g. to convert from binary to hex, convert to decimal first and then that to hex. Base conversion is also trivial to implement in a generic way that can handle any base, given the set of digits it uses.

Also, please remember that a numeric value in memory doesn't really have the concept of a base (it's represented as binary, obviously, but that's mostly irrelevant). It's just a value. Only once you get strings involved do bases become really significant. So if your "decimal" really means a numeric value instead of a string of digits, it might be best to not call it "decimal".