more robustness for {break,turn,page}-permission

diff --git a/lily/constrained-breaking.cc b/lily/constrained-breaking.cc
index 714f8ce6eed9dc5332489d3513918fe03f591121..c688be6a1b54237b859f52375f086e9e9275da07 100644 (file)
--- a/lily/constrained-breaking.cc
+++ b/lily/constrained-breaking.cc
@@ -301,6 +301,17 @@ Constrained_breaking::Constrained_breaking (Paper_score *ps, vector<vsize> const
   initialize ();
 }
 
+static SCM
+min_permission (SCM perm1, SCM perm2)
+{
+  if (perm1 == ly_symbol2scm ("force"))
+    return perm2;
+  if (perm1 == ly_symbol2scm ("allow")
+     && perm2 != ly_symbol2scm ("force"))
+    return perm2;
+  return SCM_EOL;
+}
+
 /* find the forces for all possible lines and cache ragged_ and ragged_right_ */
 void
 Constrained_breaking::initialize ()
@@ -354,6 +365,13 @@ Constrained_breaking::initialize ()
          line.break_permission_ = c->get_property ("line-break-permission");
          line.page_permission_ = c->get_property ("page-break-permission");
          line.turn_permission_ = c->get_property ("page-turn-permission");
+         
+         /* turn permission should always be stricter than page permission
+            and page permission should always be stricter than line permission */
+         line.page_permission_ = min_permission (line.break_permission_,
+                                                 line.page_permission_);
+         line.turn_permission_ = min_permission (line.page_permission_,
+                                                 line.turn_permission_);
 
          max_ext = max (max_ext, extent.length ());
          line.extent_ = extent;