pre- or post-commands

[Heikki Johannes Junes]

I tried to make some notes invisible. However, I found a strange thing
that it is not evident that which properties have to written before the
note (pre-command) and which have to written after the note
(post-command). By just probing one can find out which are pre- and
post-commands, but is there a clear conceptual distinction?

Here is the example what made me wonder:

invisiblenotes = {
  \property Voice.NoteHead \override
    #'transparent = ##t
  \property Voice.Stem \override
    #'transparent = ##t
  \property Voice.Beam \override
    #'transparent = ##t
 }

visiblenotes = {
  \property Voice.NoteHead \revert #'transparent
  \property Voice.Stem \revert #'transparent
  \property Voice.Beam \revert #'transparent
 }

\score { 
    \notes \transpose c'''
    \context Staff {
        e8 e e e e e e e
        \invisiblenotes
        e  e e e e e e e
        \visiblenotes
        e e e e e e e e
    }
}

I tested that at least there is the same behavior with 1.4.10 and 1.5.30.

--
      Heikki Junes