The most consolidated macro you can come across is if you install the addon  
  
https://github.com/DennisWG/CastModifier 
  
and your macro becomes... 
/cast !Attack
Although i kinda feel that the above addon is exclusive to supermacro. 
  
Edit: There is also a new addon from Aviana called classic macros that actually has a /startattack  
  
https://github.com/Aviana/ClassicMacros