The online game Mabinogi has a music composition feature available to characters that play as bards. Players can compose simple songs using the Music Macro Language code.
Players need the Composition skill to write music, which is obtained by reading the book "Introduction to Music Composition." Players also need to have a blank Score Scroll to use the skill. Four instrument lines can be programmed using a variation of musical notation. With a high enough rank in Musical Knowledge and Composition, magical effects can occur when a song is played. There are a number of other books that raise a player's Composition skill once it has been learned.