Type numbers, get a chart. Each line is a row of bars; numbers separated by spaces are separate bars. A line of plain text (VERSE, CHORUS x2) starts a section. The sheet on the right redraws as you type.
Qualities
Stick letters right onto the number: 1m or 1- minor, 1M major 7, 1d dominant 7 (1d9 for a 9), 1o diminished, 1oo half-diminished, 1sus. Add extensions with $: 4$6$9. Bass notes with a slash: 1/3. Flats and sharps go in front: b7.
Splitting a bar
Run numbers together to share a bar: 45 is two beats of 4, two of 5. Dots set beats when it's uneven: 4..1.5.. Brackets make a half bar [4], and % repeats the last bar.
Accents
>1 push (>>1 for a quarter push), 1& pull, ^1 marcato, <1> diamond.
Form
Repeat signs with braces: {1 4 5}x2. First and second endings start a line with 1) / 2). Repeat a whole row with x3 on its own line. --- forces a new column on the sheet.
Notes — three kinds
1 4(let ring) 5small note above that bar — let ring
1 4(_tacet) 5start with _ to put the note under the bar
1 (hold)4 5glue a note to the front of a bar to attach it to that bar
"swing feelitalic note on its own line — swing feel
!WAIT FOR CUEbig boxed instruction — WAIT FOR CUE
The full symbol key lives under the editor, bottom left.