Ctrl+Alt+Space plays the cursor's bar and stops at the next bar line, so the
same bar can be fired repeatedly while nudging a note without reaching for
stop. Alt+Space keeps its play-onwards behaviour.
The stop is performed by the preview daemon rather than the action script: a
script that stayed alive waiting for the bar to end would bring back REAPER's
"already running" prompt on the next press, which is the problem the daemon
exists to avoid. Stopping transport can move the edit cursor depending on
preferences, and the edit cursor is the grid cursor, so the daemon restores it.
A short arming window covers the gap between requesting playback and the
transport reporting as playing, so the pending stop is not cancelled instantly.
Alt+Space plays from the downbeat of the bar the cursor is in. Auditioning a
cell says what a note is; playing from the bar line says whether it is in the
right place, which is the question that matters at 16ths and 32nds and cannot
be answered from a note in isolation.
REAPER can almost do this by chaining a go-to-measure action with play, but
that leaves the edit cursor at the bar line -- and the edit cursor is the grid
cursor, so you would lose your editing position every time you listened. Here
the cursor is moved just long enough to start playback and then restored with
seekplay=false so the restore cannot drag playback with it.
Works regardless of grid mode, being a listening aid rather than an edit.
Talon