How to view the ("full") input that lilypond is engraving?

[Jaime T]

http://lilypond.org/doc/v2.19/Documentation/notation/file-structure
(NR, section 3.1.5 "File structure") says:

...A file containing only "{ c'4 d' e'2 }" will be translated into:

\book {
  \score {
    \new Staff {
      \new Voice {
        { c'4 d' e'2 }
      }
    }
    \layout { }
  }
  \paper { }
  \header { }
}

Is there any way I can get lilypond to output and show me the final
version of my input i.e. *after* lilypond has included all these
necessary implicit additions to my source input?

I'd love to be able to see exactly what goes into the engraver's
front-end (and I'm sure that it's often *not* the same as what is in
my .ly "source"!)

Thank you.