[incudine-devel] New DOVOICES macro to iterate over the allocated voices

[Tito L. <tit...@gm...>]

The syntax is

    voicer:dovoices (tag-var voicer &optional result) &body body

>From the documentation:

Iterate over the allocated voices of the given VOICER, in allocation order,
with TAG-VAR bound to each identifier tag, then RESULT form is evaluated.

Note: the iteration occurs in rt-thread before or after trigger/release,
therefore the audio cycle is possibly blocked during BODY.
See INCUDINE:NRT-FUNCALL to call a function from audio-nrt-thread.

Example:

;; The voices are allocated with a numerical tag where the LSB
;; is the keynum and the MSB is an exclusive group number.
;; A voice is released if the exclusive group number is 3.

(voicer:dovoices (tag v)
  (if (= 3 (ash tag -8)) (voicer:release v tag)))