Add comparison functions

lib/chervil/core.rb

@@ -1,10 +1,28 @@
 module Chervil
   module Core
+    def self.compare_pairs(ary, method)
+      pairs = Array.new
+      ary.each_with_index do |el, i|
+        unless ary[i + 1].nil?
+          pairs.push([el, ary[i + 1]])
+        end
+      end
+
+      !(pairs.map { |pair| pair[0].send(method, pair[1]) }.any?(false))
+    end
+
     CORE = {
       "+" => Proc.new { |args| args.inject(:+) },
       "-" => Proc.new { |args| args.inject(:-) },
       "*" => Proc.new { |args| args.inject(:*) },
       "/" => Proc.new { |args| args.inject(:/) },
+      "=" => Proc.new { |args| compare_pairs(args, :==) },
+      "<" => Proc.new { |args| compare_pairs(args, :<) },
+      ">" => Proc.new { |args| compare_pairs(args, :>) },
+      "<=" => Proc.new { |args| compare_pairs(args, :<=) },
+      ">=" => Proc.new { |args| compare_pairs(args, :>=) },
+      "and" => Proc.new { |args| !(args.include?(false)) },
+      "or" => Proc.new { |args| args.any? { |arg| !!arg == true } },
     }
   end
 end