mapping a markup-command across strings in lyricmode

[Mark Polesky]

I wrote a markup command which takes a string and parses
it to make a special markup.  I'm leaving out the details,
but the input might look something like:

\markup \foo #"abc123"

I want to use this in a Lyrics context, but constantly
retyping "\markup \foo #" is annoying and takes up a lot
of space in my file:

\lyricmode {
  \markup \foo #"abc123" __ _
  \markup \foo #"def456"
  \markup \foo #"ghi789" __ _ _
}

Is there a way to simplify the user interface?  This would
be ideal, but I'm open to other suggestions:

\lyricmode \mapFoo {
  "abc123" __ _ "def456" "ghi789" __ _ _
}

Thanks.
- Mark