X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fpaper-column.cc;h=bcb480451507ccbbde9553d113e90bd1bb772df2;hb=97a0169312a260933246ab224e4f8b0969871dd5;hp=d907acdf24f914e9b435aca0c92b44a46c149d96;hpb=fe4893be240c78a35deff5e86af3d7d1200a478b;p=lilypond.git

diff --git a/lily/paper-column.cc b/lily/paper-column.cc
index d907acdf24..bcb4804515 100644
--- a/lily/paper-column.cc
+++ b/lily/paper-column.cc
@@ -203,13 +203,14 @@ Paper_column::break_align_width (Grob *me, SCM align_syms)
           (me, ly_symbol2scm ("elements"),
            (scm_is_eq (align_sym, ly_symbol2scm ("staff-bar"))
             ? Bar_line::non_empty_barline
-            : Break_alignment_interface::has_interface));
+            : has_interface<Break_alignment_interface>));
       else
         {
           extract_grob_set (me, "elements", elts);
           for (vsize i = 0; i < elts.size (); i++)
             {
-              if (elts[i]->get_property ("break-align-symbol") == align_sym
+              if (scm_is_eq (align_sym, elts[i]->get_property ("break-align-symbol"))
+                  // TODO SCM: there must be a simpler way to put this.
                   && !elts[i]->extent (elts[i], X_AXIS).is_empty ())
                 {
                   align = elts[i];
@@ -225,6 +226,22 @@ Paper_column::break_align_width (Grob *me, SCM align_syms)
   return align->extent (p, X_AXIS);
 }
 
+LY_DEFINE (ly_paper_column__break_align_width, "ly:paper-column::break-align-width",
+           2, 0, 0, (SCM col, SCM align_syms),
+           "Determine the extent along the X-axis of a grob used for"
+           " break-alignment organized by column @var{col}. The grob is"
+           " specified by @var{align-syms}, which contains either a"
+           " single @code{break-align-symbol} or a list of such"
+           " symbols.")
+{
+  LY_ASSERT_SMOB (Grob, col, 1);
+  SCM_ASSERT_TYPE (scm_is_symbol (align_syms) || ly_is_list (align_syms),
+                   align_syms, SCM_ARG2, __FUNCTION__, "symbol or list");
+
+  Interval ext = Paper_column::break_align_width (unsmob<Grob> (col), align_syms);
+  return ly_interval2scm (ext);
+}
+
 /*
   Loop through elements of a PaperColumn, find all grobs implementing specified
   interface and return their combined extent.
@@ -390,6 +407,11 @@ Paper_column::print (SCM p)
   return t.smobbed_copy ();
 }
 
+static bool grob_is_live (const Grob *g)
+{
+  return g && g->is_live ();
+}
+
 /*
   This is all too hairy. We use bounded-by-me to make sure that some
   columns are kept "alive". Unfortunately, when spanners are suicided,
@@ -404,21 +426,8 @@ Paper_column::before_line_breaking (SCM grob)
 {
   Grob *me = unsmob<Grob> (grob);
 
-  SCM bbm = me->get_object ("bounded-by-me");
-  Grob_array *ga = unsmob<Grob_array> (bbm);
-  if (!ga)
-    return SCM_UNSPECIFIED;
-
-  vector<Grob *> &array (ga->array_reference ());
-
-  for (vsize i = array.size (); i--;)
-    {
-      Grob *g = array[i];
-
-      if (!g || !g->is_live ())
-        /* UGH . potentially quadratic. */
-        array.erase (array.begin () + i);
-    }
+  if (Grob_array *ga = unsmob<Grob_array> (me->get_object ("bounded-by-me")))
+    ga->filter (grob_is_live);
 
   return SCM_UNSPECIFIED;
 }
@@ -440,7 +449,7 @@ Paper_column::is_extraneous_column_from_ligature (Grob *me)
   bool has_notehead = false;
   for (vsize i = 0; i < elts.size (); i++)
     {
-      if (Rhythmic_head::has_interface (elts[i]))
+      if (has_interface<Rhythmic_head> (elts[i]))
         {
           has_notehead = true;
           if (dynamic_cast<Item *> (elts[i])->get_column () == me)