Automatic table of contents:

Automatic table of contents:

 - markups used for building the table of contents (its title, the
 text/page-number lines) are defined as \paper variables, like the
 titling markups;

 - A music function is defined to place a label and push a (label
 paper-markup-variable text-markup) element to a list of toc items;

 - a \table-of-contents markup list command reads this toc items list to
 generate the table of contents.