#124 XML: Handling \bar

With this commit \bar is inserted properly.
Previously any mid-measure bar would end up to the right,
any at-measure bar would create a new measure.

Now mid-measure bars are inserted in place (with location="middle")
while at-measure barlines will be moved to the end of the *previous*
measure.

ly/musicxml/create_musicxml.py

@@ -121,6 +121,25 @@ def create_measure(self, pickup = False, **bar_attrs):
         if bar_attrs:
             self.new_bar_attr(**bar_attrs)
 
+    def get_previous_bar(self):
+        """ Return the previous bar or False if we're in the first. """
+        siblings = self.current_part.getchildren()
+        curr_index = siblings.index(self.current_bar)
+        if curr_index == 0:
+            return False
+        else:
+            return siblings[curr_index - 1]
+
+    def get_next_bar(self):
+        """ Return the next bar or False if we're in the last. """
+        siblings = self.current_part.getchildren()
+        curr_index = siblings.index(self.current_bar)
+        if curr_index == len(siblings) - 1:
+            return False
+        else:
+            return siblings[curr_index + 1]
+
+
     ##
     # High-level node creation
     ##
@@ -504,6 +523,21 @@ def create_bar_attr(self):
         """Create node attributes """
         self.bar_attr = etree.SubElement(self.current_bar, "attributes")
 
+    def create_barline(self, bar_style, ends_bar):
+        """Create a barline, either at the current position
+        or at the end of the previous bar. """
+        if ends_bar:
+            # This is necessary because when the user writes \bar as a bar end
+            # we are already in the next measure.
+            bar = self.get_previous_bar()
+            location = 'right'
+        else:
+            bar = self.current_bar
+            location = 'middle'
+        bl = etree.SubElement(bar, "barline", {'location': location})
+        bs = etree.SubElement(bl, 'bar-style')
+        bs.text = bar_style
+
     def add_divisions(self, div):
         division = etree.SubElement(self.bar_attr, "divisions")
         division.text = str(div)

ly/musicxml/ly2xml_mediator.py

@@ -335,11 +335,12 @@ def add_to_bar(self, obj):
             self.new_bar()
         self.bar.add(obj)
 
-    def create_barline(self, bl):
-        barline = xml_objs.BarAttr()
-        barline.set_barline(bl)
-        self.bar.add(barline)
-        self.new_bar()
+    def new_barline(self, bl):
+        if not self.bar:
+            # \bar at the very beginning is ignored
+            return
+        ends_bar = not self.bar.has_music()
+        self.bar.add(xml_objs.BarLine(bl, ends_bar))
 
     def new_repeat(self, rep):
         barline = xml_objs.BarAttr()

ly/musicxml/lymus2musxml.py

@@ -94,22 +94,22 @@ def __init__(self):
 
     def parse_text(self, ly_text, filename=None):
         """Parse the LilyPond source specified as text.
-        
+
         If you specify a filename, it can be used to resolve \\include commands
         correctly.
-        
+
         """
         doc = ly.document.Document(ly_text)
         doc.filename = filename
         self.parse_document(doc)
 
     def parse_document(self, ly_doc, relative_first_pitch_absolute=False):
         """Parse the LilyPond source specified as a ly.document document.
-        
+
         If relative_first_pitch_absolute is set to True, the first pitch in a
         \relative expression without startpitch is considered to be absolute
         (LilyPond 2.18+ behaviour).
-        
+
         """
         # The document is copied and the copy is converted to absolute mode to
         # facilitate the export. The original document is unchanged.
@@ -540,7 +540,7 @@ def MarkupList(self, markuplist):
     def String(self, string):
         prev = self.get_previous_node(string)
         if prev and prev.token == '\\bar':
-            self.mediator.create_barline(string.value())
+            self.mediator.new_barline(string.value())
 
     def LyricsTo(self, lyrics_to):
         r"""A \lyricsto expression. """
@@ -682,7 +682,7 @@ def End(self, end):
 
     def get_previous_node(self, node):
         """ Returns the nodes previous node
-        or false if the node is first in its branch. """
+        or False if the node is first in its branch. """
         parent = node.parent()
         i = parent.index(node)
         if i > 0:

ly/musicxml/xml_objs.py

@@ -125,11 +125,13 @@ def iterate_bar(self, bar):
             elif isinstance(obj, BarBackup):
                 divdur = self.count_duration(obj.duration, self.divisions)
                 self.musxml.add_backup(divdur)
+            elif isinstance(obj, BarLine):
+                self.musxml.create_barline(obj.bar_style, obj.ends_bar)
 
     def new_xml_bar_attr(self, obj):
         """Create bar attribute xml-nodes."""
         if obj.has_attr():
-            self.musxml.new_bar_attr(obj.clef, obj.time, obj.key, obj.mode, 
+            self.musxml.new_bar_attr(obj.clef, obj.time, obj.key, obj.mode,
                 obj.divs, obj.multirest)
         if obj.new_system:
             self.musxml.new_system(obj.new_system)
@@ -523,6 +525,17 @@ def inject_voice(self, new_voice, override=False):
                 self.add(bl)
 
 
+class BarLine():
+    """ Represents a manual bar line, needed for in-measure barlines
+    or for special-style barlines."""
+    def __init__(self, bar_style, ends_bar):
+        self.bar_style = convert_barl(bar_style)
+        self.ends_bar = ends_bar
+
+    def __repr__(self):
+        return '<{0} {1}>'.format(self.__class__.__name__, self.bar_style)
+
+
 class BarMus():
     """ Common class for notes and rests. """
     def __init__(self, duration, voice=1):