Editing WoW:Creating a slash command (section)

== Parsing Arguments ==
If the user types '/yourcmd someargs' into chat, the function handling '/yourcmd' is passed 'someargs' as the first argument we have been naming 'msg', with the second argument as the chat edit box widget. Your handler function can then choose to act on that argument string. For simple slash commands, comparisons to pre-determined strings may be sufficient. Suppose we wanted to modify the "Hello, World!" example above to display a different string if the command was passed an argument, say "/hiw bye".

 local function MyAddonCommands(msg, editbox)
   if msg == 'bye' then
     print('Goodbye, World!')
   else
     print("Hello, World!")
   end
 end
 
 SLASH_HELLOWORLD1, SLASH_HELLOWORLD2 = '/hiw', '/hellow'
 
 SlashCmdList["HELLOWORLD"] = MyAddonCommands   -- add /hiw and /hellow to command list

Here is a more complex slash command example that is able to process arguments for commands that uses Lua [[Pattern matching]] to parse the arguments string:

 local function MyAddonCommands(msg, editbox)
   -- pattern matching that skips leading whitespace and whitespace between cmd and args
   -- any whitespace at end of args is retained
   local _, _, cmd, args = string.find(msg, "%s?(%w+)%s?(.*)")
    
   if cmd == "add" and args ~= "" then
     print("adding " .. args)
     -- Handle adding of the contents of rest... to something.
   elseif cmd == "remove" and args ~= "" then
     print("removing " .. args)
     -- Handle removing of the contents of rest... to something.   
   else
     -- If not handled above, display some sort of help message
     print("Syntax: /hellow (add|remove) someIdentifier");
   end
 end
 
 SLASH_HELLOWORLD1, SLASH_HELLOWORLD2 = '/hiw', '/hellow'
 
 SlashCmdList["HELLOWORLD"] = MyAddonCommands   -- add /hiw and /hellow to command list