[patch] abc2ly and alternatives 2/3 and 3/3

[glambrouin]

This one fixes the problems 2 and 3 that I reported to the bug-lilypond
list.

Problem 2: Invalid conversion of repeat/alternative/repeat sequence.
This one is solved by closing the alternative block if we are in an
alternative when we encounter a new repeat opener.

Problem 3: Second alternative not closed before the end of the tune.
With the ABC format, it is not possible to mark the end of the second
alternative. So the problem is solved by counting the number of bars in
the first alternative, and by closing the second alternative when that
same number of bars has been reached.

I tested this patch against a set of ABC files that I wrote. This does
not prove that I did not introduce any regression...

Gwenael

diff --git a/scripts/abc2ly.py b/scripts/abc2ly.py
index 605d82d..252f125 100644
--- a/scripts/abc2ly.py
+++ b/scripts/abc2ly.py
@@ -1111,10 +1111,11 @@ repeat_ender = ['::', ':|']
 repeat_opener = ['::', '|:']
 in_repeat = [''] * 8
 doing_alternative = [''] * 8
+alternative_bar_count = [0] * 8
 using_old = ''
 
 def try_parse_bar (str,state):
-    global in_repeat, doing_alternative, using_old
+    global in_repeat, doing_alternative, alternative_bar_count, using_old
     do_curly = ''
     bs = None
     if current_voice_idx < 0:
@@ -1128,12 +1129,27 @@ def try_parse_bar (str,state):
             else:
                 bs = "%s" % bar_dict[s]
             str = str[trylen:]
+
             if s in alternative_opener:
                 if not in_repeat[current_voice_idx]:
                     using_old = 't'
                     bs = "\\bar \"%s\"" % old_bar_dict[s]
                 else:
-                    doing_alternative[current_voice_idx] = 't'
+                    if s == '|1':
+                        doing_alternative[current_voice_idx] = '1'
+                        alternative_bar_count[current_voice_idx] = 0
+                    else: # '|2' or ':|2'
+                        doing_alternative[current_voice_idx] = '2'
+                        alternative_bar_count[current_voice_idx] += 1
+            else:
+                if doing_alternative[current_voice_idx] == '1':
+                    alternative_bar_count[current_voice_idx] += 1
+                elif doing_alternative[current_voice_idx] == '2':
+                    alternative_bar_count[current_voice_idx] -= 1
+                    if alternative_bar_count[current_voice_idx] == 0:
+                        do_curly = '2'
+                        doing_alternative[current_voice_idx] = ''
+                        in_repeat[current_voice_idx] = ''
 
             if s in repeat_ender:
                 if not in_repeat[current_voice_idx]:
@@ -1142,20 +1158,28 @@ def try_parse_bar (str,state):
                     in_repeat[current_voice_idx] = ''
                 else:
                     if doing_alternative[current_voice_idx]:
-                        do_curly = 't'
+                        do_curly = '1'
                 if using_old:
                     bs = "\\bar \"%s\"" % old_bar_dict[s]
                 else:
                     bs =  bar_dict[s]
                 doing_alternative[current_voice_idx] = ''
                 in_repeat[current_voice_idx] = ''
+                
             if s in repeat_opener:
+                if doing_alternative[current_voice_idx]:
+                    doing_alternative[current_voice_idx] = ''
+                    if s == '::':
+                        do_curly = '1'
+                    else: # '|:'
+                        do_curly = '2'
                 in_repeat[current_voice_idx] = 't'
                 if using_old:
                     bs = "\\bar \"%s\"" % old_bar_dict[s]
                 else:
                     bs =  bar_dict[s]
             break
+
     if str[:1] == '|':
         state.next_bar = '|\n'
         str = str[1:]
@@ -1170,10 +1194,13 @@ def try_parse_bar (str,state):
     if bs <> None:
         clear_bar_acc(state)
         close_beam_state(state)
-        voices_append (bs)
         if do_curly != '':
-            voices_append("} ")
+            if do_curly == '2':
+                voices_append("} } ")
+            else:
+                voices_append("} ")
             do_curly = ''
+        voices_append (bs)
     return str
 
 def try_parse_tie (str):