July 24, 2009 14:00 · Jul 24, 2009
diff --git a/snippet.txt b/snippet.txt
@@ -0,0 +1,76 @@
+# Make a class that mixins Comparable and defines <=> so it gets all <, ==, >, etc.
+# Other methods like Array.sort will now work too
+
+>> class Box
+>>   def <=>(other)
+>>     [source, color] <=> [other.source, other.color]
+>>   end
+>>   attr_accessor :color, :source
+>>   include Comparable
+>> end
+>> a, b = Box.new, Box.new
+=> [#<Box:0x5627dc>, #<Box:0x5627c8>]
+>> a.color = 'red'; a.source = 'MN'
+=> "MN"
+>> b.color = 'red'; b.source = 'MN'
+=> "MN"
+>> a == b
+=> true
+>> a.color = 'blue'
+=> "blue"
+>> a == b
+=> false
+
+
+# Make more boxes and sort dem! AZ (John McCain!) comes first
+
+>> c, d = a.dup, a.dup
+=> [#<Box:0x54b5dc @source="MN", @color="blue">, #<Box:0x54b5c8 @source="MN", @color="blue">]
+>> c.source = 'AZ'
+=> "AZ"
+>> boxes = [a,b,c,d]
+=> [#<Box:0x5627dc @source="MN", @color="blue">, #<Box:0x5627c8 @source="MN", @color="red">, #<Box:0x54b5dc @source="AZ", @color="blue">, #<Box:0x54b5c8 @source="MN", @color="blue">]
+>> boxes.sort 
+=> [#<Box:0x54b5dc @source="AZ", @color="blue">, #<Box:0x5627dc @source="MN", @color="blue">, #<Box:0x54b5c8 @source="MN", @color="blue">, #<Box:0x5627c8 @source="MN", @color="red">]
+
+
+# Now i re-open the Box class and override the inspect method to give a better  output format while programming
+
+>> class Box
+>>   def inspect
+>>     "<Box #{source} #{color}>"
+>>     end
+>>   end
+=> nil
+>> boxes.sort
+=> [<Box AZ blue>, <Box MN blue>, <Box MN blue>, <Box MN red>]
+
+
+# Make a better output format that might be displayed for an end user
+>> class Box
+>>   def to_s
+>>     "#{color} Box from #{source}"
+>>     end
+>>   end
+=> nil
+>> puts boxes
+blue Box from MN
+blue Box from MN
+blue Box from AZ
+blue Box from MN
+>> "I got a #{boxes.join ', '}"
+=> "I got a blue Box from MN, blue Box from MN, blue Box from AZ, blue Box from MN"
+
+
+
+# Call map to transform each element of boxes
+# map! does the same and modifies the elements
+
+>> boxes.map {|b| b.source }
+=> ["MN", "MN", "AZ", "MN"]
+>> boxes
+=> [<Box MN blue>, <Box MN red>, <Box AZ blue>, <Box MN blue>]
+>> boxes.map! {|b| b.source }
+=> ["MN", "MN", "AZ", "MN"]
+>> boxes
+=> ["MN", "MN", "AZ", "MN"]