Karl,
Since LilyPond uses Guile, you should look up Scheme details in the Guile documentation. https://www.gnu.org/software/guile/manual/html_node/index.html The LilyPond manual just mentions the bare minimum so that you can manipulate Scheme to a certain extent. I'll massage the documentation in the LM a bit to make it more clear that people should use the Guile manual as a reference for Scheme details. > > > > In Lisp (of which Scheme is a dialect) a "symbol" is an > > > > identifier, [...] It's the same in Scheme. The Guile manual says (in section '6.6.6 Symbols): Symbols in Scheme are widely used in three ways: as items of discrete data, as lookup keys for alists and hash tables, and to denote variable references. It then goes on to give all the gory details, for example, explaining the difference between a string and a symbol. Werner
