From 887000f61099efaf85d6d5b580f20fcf84c0fc6f Mon Sep 17 00:00:00 2001
From: David Kastrup <dak@gnu.org>
Date: Wed, 27 Feb 2013 16:06:29 +0100
Subject: [PATCH] Issue 3211: Let ly_deep_copy and ly_music_deep_copy iterate
 rather than recurse for lists

Also improves DOC string of ly:music-deep-copy.
---
 lily/lily-guile.cc   | 19 +++++++++++++++++--
 lily/music-scheme.cc | 28 ++++++++++++++++++++--------
 2 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/lily/lily-guile.cc b/lily/lily-guile.cc
index eb78d8bbfd..27909a6bc2 100644
--- a/lily/lily-guile.cc
+++ b/lily/lily-guile.cc
@@ -355,8 +355,23 @@ SCM
 ly_deep_copy (SCM src)
 {
   if (scm_is_pair (src))
-    return scm_cons (ly_deep_copy (scm_car (src)), ly_deep_copy (scm_cdr (src)));
-  else if (scm_is_vector (src))
+    {
+      SCM res = SCM_EOL;
+      do
+        {
+          res = scm_cons (ly_deep_copy (scm_car (src)), res);
+          src = scm_cdr (src);
+        }
+      while (scm_is_pair (src));
+      // Oh, come on, GUILE.  Why do you require the second argument
+      // of scm_reverse_x to be a proper list?  That makes no sense.
+      // return scm_reverse_x (res, ly_deep_copy (src));
+      SCM last_cons = res;
+      res = scm_reverse_x (res, SCM_EOL);
+      scm_set_cdr_x (last_cons, ly_deep_copy (src));
+      return res;
+    }
+  if (scm_is_vector (src))
     {
       int len = scm_c_vector_length (src);
       SCM nv = scm_c_make_vector (len, SCM_UNDEFINED);
diff --git a/lily/music-scheme.cc b/lily/music-scheme.cc
index ffa903b4eb..3412e73b56 100644
--- a/lily/music-scheme.cc
+++ b/lily/music-scheme.cc
@@ -114,18 +114,30 @@ LY_DEFINE (ly_music_list_p, "ly:music-list?",
 
 LY_DEFINE (ly_music_deep_copy, "ly:music-deep-copy",
            1, 0, 0, (SCM m),
-           "Copy @var{m} and all sub expressions of@tie{}@var{m}.")
+           "Copy @var{m} and all sub expressions of@tie{}@var{m}."
+           " @var{m} may be an arbitrary type; cons cells and music"
+           " are copied recursively.")
 {
-  SCM copy = m;
   if (unsmob_music (m))
+      return unsmob_music (m)->clone ()->unprotect ();
+  if (scm_is_pair (m))
     {
-      Music *mcopy = unsmob_music (m)->clone ();
-      copy = mcopy->unprotect ();
+      SCM copy = SCM_EOL;
+      do
+        {
+          copy = scm_cons (ly_music_deep_copy (scm_car (m)), copy);
+          m = scm_cdr (m);
+        }
+      while (scm_is_pair (m));
+      // Oh, come on, GUILE.  Why do you require the second argument
+      // of scm_reverse_x to be a proper list?  That makes no sense.
+      // return scm_reverse_x (copy, ly_music_deep_copy (m));
+      SCM last_cons = copy;
+      copy = scm_reverse_x (copy, SCM_EOL);
+      scm_set_cdr_x (last_cons, ly_music_deep_copy (m));
+      return copy;
     }
-  else if (scm_is_pair (m))
-    copy = scm_cons (ly_music_deep_copy (scm_car (m)),
-                     ly_music_deep_copy (scm_cdr (m)));
-  return copy;
+  return m;
 }
 
 LY_DEFINE (ly_music_transpose, "ly:music-transpose",
-- 
2.39.2