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https://github.com/cookiengineer/audacity
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299 lines
13 KiB
Common Lisp
299 lines
13 KiB
Common Lisp
;; seq.lsp -- sequence control constructs for Nyquist
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;; get-srates -- this either returns the sample rate of a sound or a
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;; vector of sample rates of a vector of sounds
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;;
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(defun get-srates (sounds)
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(cond ((arrayp sounds)
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(let ((result (make-array (length sounds))))
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(dotimes (i (length sounds))
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(setf (aref result i) (snd-srate (aref sounds i))))
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result))
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(t
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(snd-srate sounds))))
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; These are complex macros that implement sequences of various types.
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; The complexity is due to the fact that a behavior within a sequence
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; can reference the environment, e.g. (let ((p 60)) (seq (osc p) (osc p)))
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; is an example where p must be in the environment of each member of
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; the sequence. Since the execution of the sequence elements are delayed,
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; the environment must be captured and then used later. In XLISP, the
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; EVAL function does not execute in the current environment, so a special
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; EVAL, EVALHOOK must be used to evaluate with an environment. Another
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; feature of XLISP (see evalenv.lsp) is used to capture the environment
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; when the seq is first evaluated, so that the environment can be used
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; later. Finally, it is also necessary to save the current transformation
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; environment until later.
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;; SEQ-EXPR-EXPAND - helper function, expands expression to push/pop entry
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;; on *sal-call-stack* to help debug calls into SAL from lazy evaluation
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;; of SAL code by SEQ
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(defun seq-expr-expand (expr)
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(if *sal-call-stack*
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(list 'prog2 (list 'sal-trace-enter (list 'quote (list "Expression in SEQ:" expr)))
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expr
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'(sal-trace-exit))
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expr))
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(defmacro seq (&rest list)
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(cond ((null list)
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(snd-zero (warp-time *WARP*) *sound-srate*))
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((null (cdr list))
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(car list))
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((null (cddr list))
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;; SEQ with 2 behaviors
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`(let* ((first%sound ,(seq-expr-expand (car list)))
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(s%rate (get-srates first%sound)))
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(cond ((arrayp first%sound)
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(snd-multiseq (prog1 first%sound (setf first%sound nil))
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#'(lambda (t0)
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(with%environment ',(nyq:the-environment)
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(at-abs t0
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(force-srates s%rate ,(seq-expr-expand (cadr list))))))))
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(t
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; allow gc of first%sound:
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(snd-seq (prog1 first%sound (setf first%sound nil))
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#'(lambda (t0)
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(with%environment ',(nyq:the-environment)
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(at-abs t0
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(force-srate s%rate ,(seq-expr-expand (cadr list)))))))))))
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(t ;; SEQ with more than 2 behaviors
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`(let* ((nyq%environment (nyq:the-environment))
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(first%sound ,(car list))
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(s%rate (get-srates first%sound))
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(seq%environment (getenv)))
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(cond ((arrayp first%sound)
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(snd-multiseq (prog1 first%sound (setf first%sound nil))
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#'(lambda (t0)
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(multiseq-iterate ,(cdr list)))))
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(t
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; allow gc of first%sound:
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(snd-seq (prog1 first%sound (setf first%sound nil))
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#'(lambda (t0)
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(seq-iterate ,(cdr list))))))))))
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(defun envdepth (e) (length (car e)))
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(defmacro myosd (pitch)
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`(let () (format t "myosc env depth is ~A~%"
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(envdepth (getenv))) (osc ,pitch)))
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(defmacro seq-iterate (behavior-list)
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(cond ((null (cdr behavior-list))
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;; last expression in list
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`(eval-seq-behavior ,(seq-expr-expand (car behavior-list))))
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(t ;; more expressions after this one
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`(snd-seq (eval-seq-behavior ,(seq-expr-expand (car behavior-list)))
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(evalhook '#'(lambda (t0)
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; (format t "lambda depth ~A~%" (envdepth (getenv)))
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(seq-iterate ,(cdr behavior-list)))
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nil nil seq%environment)))))
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(defmacro multiseq-iterate (behavior-list)
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(cond ((null (cdr behavior-list))
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`(eval-multiseq-behavior ,(seq-expr-expand (car behavior-list))))
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(t
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`(snd-multiseq (eval-multiseq-behavior ,(seq-expr-expand (car behavior-list)))
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(evalhook '#'(lambda (t0)
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(multiseq-iterate ,(cdr behavior-list)))
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nil nil seq%environment)))))
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(defmacro eval-seq-behavior (beh)
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`(with%environment nyq%environment
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(at-abs t0
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(force-srate s%rate ,beh))))
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(defmacro eval-multiseq-behavior (beh)
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`(with%environment nyq%environment
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(at-abs t0
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(force-srates s%rate ,beh))))
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(defmacro with%environment (env &rest expr)
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`(progv ',*environment-variables* ,env ,@expr))
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(defmacro seqrep (pair sound)
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`(let ((,(car pair) 0)
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(loop%count ,(cadr pair))
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(nyq%environment (nyq:the-environment))
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seqrep%closure first%sound s%rate)
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; note: s%rate will tell whether we want a single or multichannel
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; sound, and what the sample rates should be.
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(cond ((not (integerp loop%count))
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(error "bad argument type" loop%count))
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(t
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(setf seqrep%closure #'(lambda (t0)
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; (display "SEQREP" loop%count ,(car pair))
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(cond ((< ,(car pair) loop%count)
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(setf first%sound
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(with%environment nyq%environment
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(at-abs t0 ,sound)))
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; (display "seqrep" s%rate nyq%environment ,(car pair)
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; loop%count)
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(if s%rate
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(setf first%sound (force-srates s%rate first%sound))
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(setf s%rate (get-srates first%sound)))
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(setf ,(car pair) (1+ ,(car pair)))
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; note the following test is AFTER the counter increment
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(cond ((= ,(car pair) loop%count)
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; (display "seqrep: computed the last sound at"
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; ,(car pair) loop%count
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; (local-to-global 0))
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first%sound) ;last sound
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((arrayp s%rate)
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; (display "seqrep: calling snd-multiseq at"
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; ,(car pair) loop%count (local-to-global 0)
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; (snd-t0 (aref first%sound 0)))
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(snd-multiseq (prog1 first%sound
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(setf first%sound nil))
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seqrep%closure))
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(t
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; (display "seqrep: calling snd-seq at"
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; ,(car pair) loop%count (local-to-global 0)
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; (snd-t0 first%sound))
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(snd-seq (prog1 first%sound
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(setf first%sound nil))
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seqrep%closure))))
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(t (snd-zero (warp-time *WARP*) *sound-srate*)))))
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(funcall seqrep%closure (local-to-global 0))))))
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(defmacro trigger (input beh)
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`(let ((nyq%environment (nyq:the-environment)))
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(snd-trigger ,input #'(lambda (t0) (with%environment nyq%environment
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(at-abs t0 ,beh))))))
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;; EVENT-EXPRESSION -- the sound of the event
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;;
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(setfn event-expression caddr)
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;; EVENT-HAS-ATTR -- test if event has attribute
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;;
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(defun event-has-attr (note attr)
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(expr-has-attr (event-expression note)))
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;; EXPR-SET-ATTR -- new expression with attribute = value
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;;
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(defun expr-set-attr (expr attr value)
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(cons (car expr) (list-set-attr-value (cdr expr) attr value)))
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(defun list-set-attr-value (lis attr value)
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(cond ((null lis) (list attr value))
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((eq (car lis) attr)
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(cons attr (cons value (cddr lis))))
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(t
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(cons (car lis)
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(cons (cadr lis)
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(list-set-attr-value (cddr lis) attr value))))))
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;; EXPAND-AND-EVAL-EXPR -- evaluate a note, chord, or rest for timed-seq
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;;
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(defun expand-and-eval-expr (expr)
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(let ((pitch (member :pitch expr)))
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(cond ((and pitch (cdr pitch) (listp (cadr pitch)))
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(setf pitch (cadr pitch))
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(simrep (i (length pitch))
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(eval (expr-set-attr expr :pitch (nth i pitch)))))
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(t
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(eval expr)))))
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;; (timed-seq '((time1 stretch1 expr1) (time2 stretch2 expr2) ...))
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;; a timed-seq takes a list of events as shown above
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;; it sums the behaviors, similar to
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;; (sim (at time1 (stretch stretch1 expr1)) ...)
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;; but the implementation avoids starting all expressions at once
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;;
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;; Notes: (1) the times must be in increasing order
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;; (2) EVAL is used on each event, so events cannot refer to parameters
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;; or local variables
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;;
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;; If score events are very closely spaced (< 1020 samples), the block
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;; overlap can cause a ripple effect where to complete one block of the
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;; output, you have to compute part of the next score event, but then
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;; it in turn computes part of the next score event, and so on, until
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;; the stack overflows (if you have 1000's of events).
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;;
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;; This is really a fundamental problem in Nyquist because blocks are
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;; not aligned. To work around the problem (but not totally solve it)
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;; scores are evaluated up to a length of 100. If there are more than
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;; 100 score events, we form a balanced tree of adders so that maybe
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;; we will end up with a lot of sound in memory, but at least the
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;; stack will not overflow. Generally, we should not end up with more
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;; than 100 times as many blocks as we would like, but since the
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;; normal space required is O(1), we're still using constant space +
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;; a small constant * log(score-length).
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;;
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(setf MAX-LINEAR-SCORE-LEN 100)
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(defun timed-seq (score)
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(must-be-valid-score "TIMED-SEQ" score)
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(let ((len (length score))
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pair)
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(cond ((< len MAX-LINEAR-SCORE-LEN)
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(timed-seq-linear score))
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(t ;; split the score -- divide and conquer
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(setf pair (score-split score (/ len 2)))
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(sum (timed-seq (car pair)) (timed-seq (cdr pair)))))))
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;; score-split -- helper function: split score into two, with n elements
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;; in the first part; returns a dotted pair
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(defun score-split (score n)
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;; do the split without recursion to avoid stack overflow
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;; algorithm: modify the list destructively to get the first
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;; half. Copy it. Reassemble the list.
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(let (pair last front back)
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(setf last (nthcdr (1- n) score))
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(setf back (cdr last))
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(rplacd last nil)
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(setf front (append score nil)) ; shallow copy
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(rplacd last back)
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(cons front back)))
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;; TIMED-SEQ-LINEAR - check to insure that times are strictly increasing
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;; and >= 0 and stretches are >= 0
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(defun timed-seq-linear (score)
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(let ((start-time 0) error-msg rslt)
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(dolist (event score)
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(cond ((< (car event) start-time)
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(error (format nil
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"Out-of-order time in TIMED-SEQ: ~A, consider using SCORE-SORT"
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event)))
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((< (cadr event) 0)
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(error (format nil "Negative stretch factor in TIMED-SEQ: ~A" event)))
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(t
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(setf start-time (car event)))))
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;; remove rests (a rest has a :pitch attribute of nil)
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(setf score (score-select score #'(lambda (tim dur evt)
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(expr-get-attr evt :pitch t))))
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(cond ((and score (car score)
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(eq (car (event-expression (car score))) 'score-begin-end))
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(setf score (cdr score)))) ; skip score-begin-end data
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(cond ((null score) (s-rest 0))
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(t
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(at (caar score)
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(seqrep (i (length score))
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(progn
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(cond (*sal-call-stack*
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(sal-trace-enter (list "Score event:" (car score)) nil nil)
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(setf *sal-line* 0)))
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(setf rslt
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(cond ((cdr score)
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(prog1
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(set-logical-stop
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(stretch (cadar score)
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(expand-and-eval-expr (caddar score)))
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(- (caadr score) (caar score)))
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(setf score (cdr score))))
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(t
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(stretch (cadar score) (expand-and-eval-expr
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(caddar score))))))
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(if *sal-call-stack* (sal-trace-exit))
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rslt)))))))
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