Lilypond as a server
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lys - Run lilypond as a server

This package provides a way to keep Lilypond running in the background as a server. It then extends the lyp compile command to compile user files by sending requests to the running Lilypond instance. The server can also be connected to using telnet or from any programming language by opening a TCP port.


Because Lilypond is just too damn slow...


Install using lyp:

$ lyp install lys

Compiling using the server

To compile files using the server command, use the lyp compile command and add the -s or --server option:

$ lyp compile -s

You can of course add any other Lilypond option you wish for, e.g.:

$ lyp compile -s --png

The server is started automatically. You can kill it at any time by the usual means.

Mode of operation

The server listens on port 1225 (by default). Clients can connect and pass arbitrary scheme expressions. For example, to typeset a lilypond file, a client can send (lys:compile dir opts...) where pwd is the current working directory and opts is a list of command line options:

(lys:compile "/home/sharon" "--png" "myfile")

How fast is it?

Small files compile in 0.3-0.4s (on a modern laptop). Generally one can expect to shave 0.5-0.6s off compilation time.

Manually starting a Server

To start a server, run the following lilypond script:

\require "lys"

% listen on port 1225 ("ly" in numbers)

% to specifiy the listening port:
#(lys:start-server 12321)

Or alternatively, run from the shell:

$ lilypond -r lys -e "#(lys:start-server)"

Connecting from the shell

Commands can be sent to the server by piping to nc:

$ echo "(lys:compile-file \"~\" \"\")" | nc localhost 1225


See also the included example client.


Usage: lyp:close

Normally, a connection to the server stays open until the client disconnects. A client connecting through nc can ask the server to shutdown the connection by sending (lyp:close).


Usage: lys:compile-file pwd opt ...

Compile a lilypond file, where pwd is the client's working directory, and opt is one or more lilypond command line options. lys:compile-file currently handles all of lilypond's command line options except --loglevel and --include.

Example: (lys:compile-file "/Users/dudu" "--png" "")


Usage: lys:stdin-eval-loop

Start an evaluate loop on stdin. This can be used to start a long-running slave lilypond process that evaluates arbitrary scheme expressions received on stdin.


Usage: lys:spawn expr ...

Fork and evaluate a sequence of expressions in the child process. Returns the child pid.

Example: (lys:spawn (lys:compile-file "/Users/dudu" "--png" ""))


Usage: lys:typeset-slice music filename

Compile the given music variable into to the given output filename.

Example: (lys:typeset myMusic "my-music")


Usage: lys:typeset-slice music start-moment end-moment filename

Compile a range of the given music variable between two moments and output to the given filename. The moments are specified as lists that are converted into ly:moment.

Example: (lys:typeset-slice myMusic '(3 1) '(6 1) "music3-6")