Encapsulated the translation of the langmap including caching of results into a own object

plugin/UltiSnips/__init__.py

@@ -368,6 +368,44 @@ class Snippet(object):
             return SnippetInstance(parent, indent, v, start,
                     end, last_re = self._last_re, globals = self._globals)
 
+class LangMapTranslator(object):
+    """
+    This object cares for the vim langmap option and basically reverses
+    the mappings. This was the only solution to get UltiSnips to work
+    nicely with langmap; other stuff I tried was using inoremap movement
+    commands and caching and restoring the langmap option.
+
+    Note that this will not work if the langmap overwrites a character
+    completely, for example if 'j' is remapped, but nothing is mapped
+    back to 'j', then moving one line down is no longer possible and
+    UltiSnips will fail.
+    """
+    _maps = {}
+
+    def _create_translation(self, langmap):
+        from_chars, to_chars = "", ""
+        for c in langmap.split(','):
+            if ";" in c:
+                a,b = c.split(';')
+                from_chars += a
+                to_chars += b
+            else:
+                from_chars += c[::2]
+                to_chars += c[1::2]
+
+        self._maps[langmap] = string.maketrans(to_chars, from_chars)
+
+    def translate(self, s):
+        langmap = vim.eval("&langmap").strip()
+        if langmap == "":
+            return s
+
+        if langmap not in self._maps:
+            self._create_translation(langmap)
+
+        return s.translate(self._maps[langmap])
+
+
 class VimState(object):
     def __init__(self):
         self._abs_pos = None
@@ -446,30 +484,11 @@ class VimState(object):
             else:
                 do_select = "%ih" % (-delta.col+1)
 
-            def unmap(s):
-                from_chars, to_chars = "", ""
-                for c in vim.eval("&langmap").split(','):
-                    if ";" in c:
-                        a,b = c.split(';')
-                        from_chars += a
-                        to_chars += b
-                    else:
-                        from_chars += c[::2]
-                        to_chars += c[1::2]
+            move_cmd = LangMapTranslator().translate(
+                r"\<Esc>%sv%s%s\<c-g>" % (move_one_right, move_lines, do_select)
+            )
 
-                rv = ""
-                for c in s:
-                    if c not in from_chars:
-                        rv += c
-                        continue
-                    if c not in to_chars:
-                        raise RuntimeError, "langmap overwrite %s" % c
-                    rv += from_chars[to_chars.index(c)]
-
-                return rv
-
-            feedkeys(unmap(r"\<Esc>%sv%s%s\<c-g>" %
-                (move_one_right, move_lines, do_select)))
+            feedkeys(move_cmd)
 
 
     def buf_changed(self):