Editing WoW:Object-oriented programming (section)

=== Namespace Use ===
Many Lua programmers consider the use of Lua namespaces as an indicator of a good understanding of the language. This is because it is very organized and requires a good understanding of several language features. Encapsulating your addon within one or a few namespaces can result in allowing your addon to use a minimal number of global variables, thus minimizing its global namespace pollution.

Many addons authors create a single namespace which encapsulates all its code. This limits the addon's exposure without limiting functionality. Instead of creating 10 global functions, for example, the addon instead has a single namespace and 10 functions which are accessible within that namespace. The following code segment provides a bad example which unnecessarily pollutes the global namespace, and then provides a functionally equivalent example, which is far more organized. It creates two functions and two variables in the namespace:

   -- Pollutes the global namespace, making 2
   -- global variables and 2 global functions
   MyAddon_A = 1;
   MyAddon_B = 2;
   function MyAddon_PrintA()
      DEFAULT_CHAT_FRAME:AddMessage(MyAddon_A);
   end
   function MyAddon_PrintB()
      DEFAULT_CHAT_FRAME:AddMessage(MyAddon_B);
   end

   -- Creates a "MyAddon" namespace and then creates
   -- 2 variables, 2 functions inside it
   MyAddon = {};
   MyAddon.a = 1;
   MyAddon.b = 2;
   function MyAddon.Printa()
      DEFAULT_CHAT_FRAME:AddMessage(MyAddon.a);
   end
   function MyAddon.Printb()
      DEFAULT_CHAT_FRAME:AddMessage(MyAddon.b);
   end

As is directly evident, the appropriate use of namespaces can cause code to be far more organized and limit conflicts. This is necessary in an environment such as WoW, where several authors will write several addons, each of whom has no idea what the other is writing, and conflicts must be avoided as much as possible.