From c991eb5d49a1b36c81a890c4574f75d8834bb9a0 Mon Sep 17 00:00:00 2001
From: Trevor Daniels <t.daniels@treda.co.uk>
Date: Thu, 19 Jan 2017 20:47:36 +0000
Subject: [PATCH] Issue 185 Squishing chords

  Add a user-level interface to the event-chord-reduce function.

  Document its use for squishing chords in music being used to
  provide the rhythms to RhythmicStaff and the Pitch_squash_engraver.
---
 Documentation/notation/rhythms.itely | 16 ++++++++++++++++
 ly/music-functions-init.ly           |  6 ++++++
 2 files changed, 22 insertions(+)

diff --git a/Documentation/notation/rhythms.itely b/Documentation/notation/rhythms.itely
index 9d4a756346..8dc6252eca 100644
--- a/Documentation/notation/rhythms.itely
+++ b/Documentation/notation/rhythms.itely
@@ -1929,6 +1929,22 @@ be done with the @code{Pitch_squash_engraver} and
 >>
 @end lilypond
 
+Music containing chords can also be used as input to @code{RhythmicStaff}
+and for use with the @code{Pitch_squash_engraver} if the chords are first
+reduced to single notes with the @code{\reduceChords} music function:
+
+@lilypond[quote,verbatim]
+\new RhythmicStaff {
+  \time 4/4
+  \reduceChords {
+    <c>2
+    <e>2
+    <c e g>2
+    <c e g>4
+    <c e g>4
+  }
+}
+@end lilypond
 
 @predefined
 @code{\improvisationOn},
diff --git a/ly/music-functions-init.ly b/ly/music-functions-init.ly
index 1f94319bce..d7eba42a4b 100644
--- a/ly/music-functions-init.ly
+++ b/ly/music-functions-init.ly
@@ -1506,6 +1506,12 @@ usually contains spacers or multi-measure rests.")
                'element main-music
                'quoted-music-name what))
 
+reduceChords =
+#(define-music-function (music) (ly:music?)
+   (_i "Reduce chords contained in @var{music} to single notes,
+intended mainly for reusing music in RhythmicStaff.  Does not
+reduce parallel music.")
+   (event-chord-reduce music))
 
 relative =
 #(define-music-function (pitch music)
-- 
2.39.2