1.1.1 Scheme sandbox

The LilyPond installation includes the Guile implementation of Scheme. A hands-on Scheme sandbox with all of LilyPond loaded is available with this call on the command line:

lilypond scheme-sandbox

Once the sandbox is running, you will receive a guile prompt

guile>

which you can use to enter Scheme expressions.

The file containing the sandbox code (ly/scheme-sandbox.ly) tries to activate the GNU readline library for nicer editing on the Guile prompt (for example, using the up and down arrow keys to access previously typed commands). Currently, this only works with a LilyPond binary dynamically linked with Guile, which is not the case for the ‘officially’ distributed binaries. Two possible workarounds are as follows.

• Use rlwrap, a thin wrapper around the readline library. This program is available for Unix-like operating systems; call it with

  rlwrap lilypond scheme-sandbox
  

• Use the Emacs editor in combination with the LilyPond Tree-sitter Mode. This works under Windows, too.