From 8ab4967c376fc54b96601b7533d1e3e9af92bbfa Mon Sep 17 00:00:00 2001
From: David Kastrup <dak@gnu.org>
Date: Sat, 15 Oct 2011 10:50:18 +0200
Subject: [PATCH] Issue 1976: Handle full rational pitch differences in
 fingering calculations.

Defines and uses ly:pitch-tones for rational pitch extraction.
---
 lily/pitch-scheme.cc          | 12 +++++++++++-
 scm/tablature.scm             |  2 +-
 scm/translation-functions.scm | 10 +++++++---
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/lily/pitch-scheme.cc b/lily/pitch-scheme.cc
index ad1753251f..a188469fbd 100644
--- a/lily/pitch-scheme.cc
+++ b/lily/pitch-scheme.cc
@@ -92,7 +92,7 @@ LY_DEFINE (ly_pitch_alteration, "ly:pitch-alteration",
   return ly_rational2scm (q);
 }
 
-LY_DEFINE (pitch_notename, "ly:pitch-notename",
+LY_DEFINE (ly_pitch_notename, "ly:pitch-notename",
            1, 0, 0, (SCM pp),
            "Extract the note name from pitch @var{pp}.")
 {
@@ -102,6 +102,16 @@ LY_DEFINE (pitch_notename, "ly:pitch-notename",
   return scm_from_int (q);
 }
 
+LY_DEFINE (ly_pitch_tones, "ly:pitch-tones",
+	   1, 0, 0, (SCM pp),
+           "Calculate the number of tones of@tie{}@var{pp} from"
+           " middle@tie{}C as a rational number.")
+{
+  LY_ASSERT_SMOB (Pitch, pp, 1);
+  return ly_rational2scm (unsmob_pitch (pp)->tone_pitch ());
+}
+
+
 LY_DEFINE (ly_pitch_quartertones, "ly:pitch-quartertones",
            1, 0, 0, (SCM pp),
            "Calculate the number of quarter tones of@tie{}@var{pp} from"
diff --git a/scm/tablature.scm b/scm/tablature.scm
index 2adaaa6ed6..3304e24af7 100644
--- a/scm/tablature.scm
+++ b/scm/tablature.scm
@@ -107,7 +107,7 @@
          (left-pitch (ly:event-property (event-cause left-bound) 'pitch))
          (right-pitch (ly:event-property (event-cause right-bound) 'pitch)))
 
-    (if (< (ly:pitch-semitones right-pitch) (ly:pitch-semitones left-pitch))
+    (if (< (ly:pitch-tones right-pitch) (ly:pitch-tones left-pitch))
         -0.75
         0.75)))
 
diff --git a/scm/translation-functions.scm b/scm/translation-functions.scm
index 2dd8d2d92c..33acfbc7b4 100644
--- a/scm/translation-functions.scm
+++ b/scm/translation-functions.scm
@@ -286,7 +286,7 @@ along with @var{minimum-fret}, @var{maximum-stretch}, and
     (define (calc-fret pitch string tuning)
       "Calculate the fret to play @var{pitch} on @var{string} with
 @var{tuning}."
-      (- (ly:pitch-semitones pitch) (ly:pitch-semitones (list-ref tuning (1- string)))))
+      (* 2  (- (ly:pitch-tones pitch) (ly:pitch-tones (list-ref tuning (1- string))))))
 
     (define (note-pitch note)
       "Get the pitch (in semitones) from @var{note}."
@@ -342,6 +342,7 @@ notes?"
 	(and (or (and (not restrain-open-strings)
 		      (eq? fret 0))
 		 (>= fret minimum-fret))
+	     (integer? fret)
 	     (close-enough fret))))
 
     (define (open-string string pitch)
@@ -356,7 +357,10 @@ the current tuning?"
 				  tuning)))
 	(if (< this-fret 0)
 	  (ly:warning (_ "Negative fret for pitch ~a on string ~a")
-		      (car pitch-entry) string))
+		      (car pitch-entry) string)
+	  (if (not (integer? this-fret))
+	      (ly:warning (_ "Missing fret for pitch ~a on string ~a")
+			  (car pitch-entry) string)))
 	(delete-free-string string)
         (set! specified-frets (cons this-fret specified-frets))
         (list-set! string-fret-fingers
@@ -415,7 +419,7 @@ the current tuning?"
 		            (ly:context-property context
 					         'handleNegativeFrets
 					         'recalculate)))
-		      (cond ((or (>= this-fret 0)
+		      (cond ((or (and (>= this-fret 0) (integer? this-fret))
 			         (eq? handle-negative 'include))
                              (set-fret! pitch-entry string finger))
 		            ((eq? handle-negative 'recalculate)
-- 
2.39.5