With obj:Obj Do command

 With obj:Obj [Do]
   commands
 EndWith

Evaluate command in object context. The expression obj specifies an object, such as a planet (Planet(14)). That object's context is activated, and all commands are executed within it. For example, within a planet context, SetFCode would change the planet's friendly code, and the FCode property would return it.

See also: Elementary Commands