>> (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 _______________________________________________ lilypond-devel mailing list lilypond-devel@gnu.org https://lists.gnu.org/mailman/listinfo/lilypond-devel