Re: Interplay between keepWithTag and relative music

[David Kastrup]

Patrick or Cynthia Karl <address@hidden> writes:

> So I guess I don't understand the subject interplay.  Consider the
> following minimal example:
>
> \version "2.18.0"
>
> A = \relative g' {
>   c c c c
>   \tag #'up   { c' c c c }
>   \tag #'down { c, c c c }
>   c c c c
> }
>
> \score {
>   \keepWithTag #'up \A
> }

> I expect that all I need is a pointer to the appropriate documentation
> that explains this.

<URL:http://lilypond.org/doc/v2.18/Documentation/notation/different-editions-from-one-source#using-tags>

Scroll down to:

Known issues and warnings

Calling \relative on a music expression obtained by filtering music
through \keepWithTag or \removeWithTag might cause the octave relations
to change, as only the pitches actually remaining in the filtered
expression will be considered. Applying \relative first, before
\keepWithTag or \removeWithTag, avoids this danger as \relative then
acts on all the pitches as-input.

-- 
David Kastrup