MuseScore lets you notate and compose music easily with your keyboard, your mouse, or a MIDI keyboard. You can print beautifully engraved sheet music or export it as PDF or PNG. You can play your score, transpose it, and save it as audio or MIDI file. MuseScore also supports MusicXML to let you share your composition with other scorewriters. MuseScore is often advertised as a cost effective alternative for Sibelius and Finale.
MMLi is a simple Music Macro Language interpreter written in ISO C99. The Music Macro Language originated in 8-bit BASIC implementations (as part of the “PLAY” command), and can still be found in modern BASICs (like QB64) and in system software (like FreeBSD's spkr.c driver.) This interpreter features an example "mmlitest" program which can be used to translate MML sequences into beep(1) commandline arguments.