Part_combine_iterator: simplify context substitution (issue 238070043 by address@hidden)

[nine . fierce . ballads]

Reviewers: ,

Description:
Part_combine_iterator: simplify context substitution.  There are no
regression test differences, but I'm concerned that there might be a
reason for the way this was written that the tests do not exercise.

Music_iterator::substitute_outlet: do nothing if the new outlet is
identical to the old (a sanity test)

Please review this at https://codereview.appspot.com/238070043/

Affected files (+10, -13 lines):
  M lily/music-iterator.cc
  M lily/part-combine-iterator.cc


Index: lily/music-iterator.cc
diff --git a/lily/music-iterator.cc b/lily/music-iterator.cc
index  
8eb238c295bc6d95e47187e6995358e9ac4ab01d..dabcccfb25aaeb4b56160e550155df72ab18338c  
100644
--- a/lily/music-iterator.cc
+++ b/lily/music-iterator.cc
@@ -132,9 +132,12 @@ Music_iterator::init_context (Music *m, Context  
*report)
 void
 Music_iterator::substitute_outlet (Context *f, Context *t)
 {
-  if (get_outlet () == f)
-    set_context (t);
-  derived_substitute (f, t);
+  if (f != t)
+    {
+      if (get_outlet () == f)
+        set_context (t);
+      derived_substitute (f, t);
+    }
 }

 void
Index: lily/part-combine-iterator.cc
diff --git a/lily/part-combine-iterator.cc b/lily/part-combine-iterator.cc
index  
4d1baec7568b3d24939dac9c7bdac59b5467ad00..880129d8e1d78d42b8d317619bf8ddb385530384  
100644
--- a/lily/part-combine-iterator.cc
+++ b/lily/part-combine-iterator.cc
@@ -198,16 +198,10 @@ void
 Part_combine_iterator::substitute_both (Outlet_type to1,
                                         Outlet_type to2)
 {
-  Outlet_type tos[] = {to1, to2};
-
-  Music_iterator *mis[] = {first_iter_, second_iter_};
-
-  for (int i = 0; i < 2; i++)
-    {
-      for (int j = 0; j < NUM_OUTLETS; j++)
-        if (j != tos[i])
-          mis[i]->substitute_outlet (handles_[j].get_context (),  
handles_[tos[i]].get_context ());
-    }
+  first_iter_->substitute_outlet (first_iter_->get_outlet (),
+                                  handles_[to1].get_context ());
+  second_iter_->substitute_outlet (second_iter_->get_outlet (),
+                                   handles_[to2].get_context ());

   for (int j = 0; j < NUM_OUTLETS; j++)
     {