Any number of spaces and tabs can be put in almost anywhere except in the middle of a word. Each statement goes on a separate line. Blank lines can be put between statements to make things easier to read.
Comments begin with two slashes and continue to end of line.
All comments will be totally ignored by Mup, and are for your own use to remind yourself of something. Several different units are used for distances. One stepsize is half the distance between two staff lines. The actual distance on the page will vary depending on how Mup determines notes should be placed. Upper and lower case letters are not interchangeable.