[LyX/master] Fix reversion of beamer documents.

[Enrico Forestieri]

commit cda00d8329a98f912036436b3e0dcfef7cdb24e3
Author: Enrico Forestieri <for...@lyx.org>
Date:   Mon May 19 19:39:51 2014 +0200

    Fix reversion of beamer documents.
    
    Beamer documents do not have a "--Separator--" layout but a
    "Separator" one. Also fix a thinko causing the deletion of
    "\end_layout" tags in some cases.

diff --git a/lib/lyx2lyx/lyx_2_2.py b/lib/lyx2lyx/lyx_2_2.py
index 99236ff..64ff108 100644
--- a/lib/lyx2lyx/lyx_2_2.py
+++ b/lib/lyx2lyx/lyx_2_2.py
@@ -144,7 +144,13 @@ def convert_separator(document):
 def revert_separator(document):
     " Revert separator insets to layout separators "
 
-    parsep = ["\\begin_layout --Separator--", "", "\\end_layout", ""]
+    beamer_classes = ["beamer", "article-beamer", "scrarticle-beamer"]
+    if document.textclass in beamer_classes:
+        beglaysep = "\\begin_layout Separator"
+    else:
+        beglaysep = "\\begin_layout --Separator--"
+
+    parsep = [beglaysep, "", "\\end_layout", ""]
     comert = ["\\begin_inset ERT", "status collapsed", "",
               "\\begin_layout Plain Layout", "%", "\\end_layout",
               "", "\\end_inset", ""]
@@ -222,15 +228,18 @@ def revert_separator(document):
                         and not check_token(document.body[k], "\\end_deeper") \
                         and not check_token(document.body[k], 
"\\begin_deeper"):
                     if layoutname == "Standard":
-                        document.body[beg:j+1] = ["\\begin_layout 
--Separator--"]
+                        document.body[beg:j+1] = [beglaysep]
                         i = i + 1
                     else:
-                        document.body[beg:j+1] = ["\\begin_deeper", 
"\\begin_layout --Separator--"]
+                        document.body[beg:j+1] = ["\\begin_deeper", beglaysep]
                         end = end + 2 - (j + 1 - beg)
                         document.body[end+1:end+1] = ["", "\\end_deeper", ""]
                         i = i + 3
                 else:
-                    del document.body[i:end+1]
+                    if something_before:
+                        del document.body[i:end+1]
+                    else:
+                        del document.body[i:end-1]
 
         i = i + 1