Place to write piano dynamics

[Michael Pozhidaev]

Hello, everybody!

It is my first posting to this list. I am blind programmer from Russia
and music takes a very important part in my life. Lilypond is just brilliant 
software 
for me. Now I can make my own music publications by myself. Great thanks 
to everybody, who made it possible!

There is one thing I cannot understand . In many examples 
notes are not written in "\new Staff" block directly,
but placed in something like 
         upper = \relative c'' {
           \clef treble
           \key c \major
           \time 4/4
           a4 b c d  
         }

What is the advantage of such approach? I am asking,
because in "Piano centered dynamics" example melody and dynamics are written 
separately.
In long composition it can be difficult to
think about a correct place for dynamics.

Are there problems to write melody and dynamics together? And why using special 
blocks 
for melody in most cases is more convenient?

Thanks!
-- 
With best wishes, Michael Pozhidaev.
Tomsk state university, computer science department.
ALTLinux Team.