diff base/generics.lisp @ 175:7e8d95d00267

Bars independant of time sigs

darcs-hash:20080313112352-40ec0-0805528027499f30d3812fa6c4e65596d1ff40fe.gz

--- a/base/generics.lisp	Thu Mar 13 11:22:29 2008 +0000
+++ b/base/generics.lisp	Thu Mar 13 11:23:52 2008 +0000
@@ -409,3 +409,49 @@
 ;;; Dynamics 
 ;;; Voice 
 ;;; Boundary Strength (phrasing) 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;
+;; Experimental:
+;;
+
+;;; Proposed new metre functions
+;; These should provide sufficient functionality that the users need
+;; not refer to get-applicable-time-signatures unless they really mean
+;; it. In turn, this means that barline based representations have a
+;; better chance at guessing.
+
+;; Notes:
+;; * iteration is possible with
+;;     (do ((beat (current-beat (make-moment 0) composition))
+;;                (current-beat (cut-off beat) composition))) ...
+;;   [That's probably not very efficient. there must be better ways]
+;; * gsharp and tabcode can answer bar questions, but not beat
+;; questions. Appropriate conditions and restarts will be needed.
+;; * a good test of this functionality will prob be amuse-harmony.
+
+(defgeneric bar-period (time-signature implementation-object)
+  (:documentation "Returns a <period> with a duration equal to the
+  duration of a bar in the given time signature for the given
+  implementation. FIXME: this isn't guaranteed to be
+  meaningful (double time signatures break this"))
+(defgeneric current-bar (moment composition)
+  (:documentation "Returns an <anchored-period> representing the
+  bar which contains moment"))
+
+(defgeneric beat-period (moment time-signature implementation-object)
+  (:documentation "Takes a moment, time signature object and crotchet and returns
+  an <anchored-period> for the containing beat containing moment. This
+  is more useful when there's a complex time signature (not currently
+  possible) in which tactus is different in different parts of the
+  bar (e.g. 3+3+2/8)"))
+(defgeneric current-beat (moment composition)
+  (:documentation "Returns an <anchored-period> representing the
+  tactus unit which contains moment"))
+
+
+;;;;;;;;;;;;;;
+;;
+;;
+
+(defgeneric get-applicable-clefs (anchored-period constituent))