Issue 5167/6: Changes: show \markup xxx = ... \etc assignments

[lilypond.git] / lily / change-iterator.cc

diff --git a/lily/change-iterator.cc b/lily/change-iterator.cc
index 8b8f191006f90e4470d3c84831632fa7965b39d8..f70c2da47fcdd94410c1b1da34640cb403d9fc54 100644 (file)
--- a/lily/change-iterator.cc
+++ b/lily/change-iterator.cc
@@ -1,9 +1,20 @@
 /*
-  change-iterator.cc -- implement Change_iterator
+  This file is part of LilyPond, the GNU music typesetter.
 
-  source file of the GNU LilyPond music typesetter
+  Copyright (C) 1997--2015 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
-  (c) 1997--2005 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  LilyPond is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  LilyPond is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "change-iterator.hh"
@@ -15,84 +26,72 @@
 #include "warn.hh"
 
 void
-Change_iterator::error (string reason)
+Change_iterator::error (const string &reason)
 {
   string to_type = ly_symbol2string (get_music ()->get_property ("change-to-type"));
   string to_id = ly_scm2string (get_music ()->get_property ("change-to-id"));
 
   string warn1 = _f ("cannot change `%s' to `%s'", to_type, to_id)
-    + ": " + reason;
+                 + ": " + reason;
 
   /*
     GUHG!
   */
-  string warn2= "Change_iterator::process (): "
-    + get_outlet ()->context_name () + " = `"
-    + get_outlet ()->id_string () + "': ";
+  string warn2 = "Change_iterator::process (): "
+                 + get_outlet ()->context_name () + " = `"
+                 + get_outlet ()->id_string () + "': ";
   warning (warn2);
   get_music ()->origin ()->warning (warn1);
 }
 
+string
+Change_iterator::change_to (Music_iterator &it,
+                            SCM to_type,
+                            const string &to_id)
+{
+  string result; // error message
+
+  // Find the context that should have its parent changed.
+  Context *last = find_context_above_by_parent_type (it.get_outlet (), to_type);
+  if (last)
+    {
+      // Find the new parent.
+      Context *dest = find_context_near (it.get_outlet (), to_type, to_id);
+      if (dest)
+        {
+          send_stream_event (last, "ChangeParent", it.get_music ()->origin (),
+                             ly_symbol2scm ("context"), dest->self_scm ());
+        }
+      else
+        /* FIXME: constant error message.  */
+        it.get_music ()->origin ()->warning (_ ("cannot find context to switch to"));
+    }
+  else if (it.get_outlet ()->is_alias (to_type))
+    {
+      // No enclosing context of the right kind was found
+      // and the iterator's immediate context is the kind that was sought.
+
+      result = _f ("not changing to same context type: %s", ly_symbol2string (to_type).c_str ());
+    }
+  else
+    /* FIXME: incomprehensible message */
+    result = _ ("none of these in my family");
+
+  return result;
+}
+
 /*
   move to construct_children ?
 */
 void
 Change_iterator::process (Moment m)
 {
-  Context *current = get_outlet ();
-  Context *last = 0;
-
   SCM to_type = get_music ()->get_property ("change-to-type");
   string to_id = ly_scm2string (get_music ()->get_property ("change-to-id"));
 
-  /* find the type  of translator that we're changing.
-
-  If \translator Staff = bass, then look for Staff = *
-  */
-  while (current && !current->is_alias (to_type))
-    {
-      last = current;
-      current = current->get_parent_context ();
-    }
-
-  if (current && current->id_string () == to_id)
-    {
-      string msg;
-      msg += _f ("cannot change, already in translator: %s", to_id);
-    }
-
-  if (current)
-    if (last)
-      {
-       Context *dest = 0;
-       Context *where = get_outlet ();
-       while (!dest && where)
-         {
-           dest = find_context_below (where, to_type, to_id);
-           where = where->get_parent_context ();
-         }
-
-       if (dest)
-         {
-           send_stream_event (last, "ChangeParent", get_music ()->origin (),
-                              ly_symbol2scm ("context"), dest->self_scm ());
-         }
-       else
-         /* FIXME: constant error message.  */
-         get_music ()->origin ()->warning (_ ("cannot find context to switch to"));
-      }
-    else
-      {
-       /* We could change the current translator's id, but that would make
-          errors hard to catch.
-
-          last->translator_id_string () = get_change
-          ()->change_to_id_string (); */
-       error (_f ("not changing to same context type: %s", ly_symbol2string (to_type).c_str ()));
-      }
-  else
-    /* FIXME: uncomprehensable message */
-    error (_ ("none of these in my family"));
+  string msg = change_to (*this, to_type, to_id);
+  if (!msg.empty ())
+    error (msg);
 
   Simple_music_iterator::process (m);
 }