Re: [Lilypond-auto] Issue 2607 in lilypond: Patch: Allow immediate Scheme expressions to take multiple values

[Werner LEMBERG]

>>     (map! + '(1 2 3) '(4 5 6))   =>   (5 7 9)
> 
> You must not! not! not! use map! on constant lists.

Interesting.  This is something non-obvious, at least after reading
the Guile documentation.  Now, knowing what you've just written, a
second read makes much more sense, and I can see that this is hidden
in the sentence

  `map!' is allowed, but not required, to alter the cons cells of
  `lst1' ...


    Werner