15. Playing live

▶ Open in Aratu to hear and change the examples

While a piece plays, you change it; you do not rewrite it.

• Everything loops. Each line plays over and over, each over its own length.
• A change is one line. hh = cc cc oc cc replaces the hi-hat and nothing else; the other parts keep playing.
• Changes land on the beat. An edit takes effect at the next bar line; now: makes it take effect at the next beat instead: now: play fill once brings a fill in on the next beat, and the groove comes back at the bar line where it would have been.
• Prepare ahead. at bar 17: play fill schedules a change; at bar 17 beat 3: brings it in on the third beat (beat 2.5 falls between 2 and 3), and from bar 17 to 24: makes it hold for those bars only: at bar 25 what held before comes back. A line can change at a bar too: at bar 9: melody = | … | plays the new melody from bar 9, from its start. play groove 3x is the same as x3.
• Lengths. over takes bars, beats, eighths and sixteenths in cresc, fade, rit, accel, tempo ramps and parameters: piano: cresc to ff over 6 beats.
• Out and in. guitar: out silences a part from the next bar line and guitar: in brings it back; all: out stops everything. They work with at bar and every too.
• Nothing restarts. Parts keep their place in the bar when another part changes, and while the text has an error the last good version keeps playing.

The stage. To play in front of an audience, the Stage button in Play (or Ctrl+Shift+F) leaves only the code on the screen, full screen and in large type for a projector. The frame flashes on the first beat of each bar, the symbols light up as they sound and the first message shows in the corner. The buttons in the corner play and stop, change the type size (A− and A+), show the rhythm map below and leave the stage; they fade when the mouse rests. Esc leaves too. The 2 columns button splits the code in two columns, like a newspaper: the second goes on where the first ends, the two scroll together, and editing in either changes the same text.