Add the lexer for `wdiff <https://www.gnu.org/software/wdiff/>`_ output.

(issue `#960 <https://bitbucket.org/birkenfeld/pygments-main/issues/960/syntax-highlighting-for-wdiff>`_)

1 files changed, 56 insertions, 1 deletions

diff --git a/pygments/lexers/diff.py b/pygments/lexers/diff.py
index d3b1589d..9efb100b 100644
--- a/pygments/lexers/diff.py
+++ b/pygments/lexers/diff.py
@@ -9,11 +9,13 @@
     :license: BSD, see LICENSE for details.
 """
 
+import re
+
 from pygments.lexer import RegexLexer, include, bygroups
 from pygments.token import Text, Comment, Operator, Keyword, Name, Generic, \
     Literal
 
-__all__ = ['DiffLexer', 'DarcsPatchLexer']
+__all__ = ['DiffLexer', 'DarcsPatchLexer', 'WDiffLexer']
 
 
 class DiffLexer(RegexLexer):
@@ -104,3 +106,56 @@ class DarcsPatchLexer(RegexLexer):
             (r'[^\n\[]+', Generic.Deleted),
         ],
     }
+
+
+class WDiffLexer(RegexLexer):
+    """
+    A `wdiff <https://www.gnu.org/software/wdiff/>`_ lexer.
+
+    Note that:
+
+    * only to normal output (without option like -l).
+    * if target files of wdiff contain "[-", "-]", "{+", "+}",
+      especially they are unbalanced, this lexer will get confusing.
+
+    .. versionadded:: 2.1
+    """
+
+    name = 'WDiff'
+    aliases = ['wdiff',]
+    filenames = ['*.wdiff',]
+    mimetypes = []
+
+    flags = re.MULTILINE | re.DOTALL
+
+    # We can only assume "[-" after "[-" before "-]" is `nested`,
+    # for instance wdiff to wdiff outputs. We have no way to
+    # distinct these marker is of wdiff output from original text.
+
+    ins_op = r"\{\+"
+    ins_cl = r"\+\}"
+    del_op = r"\[\-"
+    del_cl = r"\-\]"
+    tokens = {
+        'root': [
+            (ins_op, Generic.Inserted, 'inserted'),
+            (del_op, Generic.Deleted, 'deleted'),
+            (r'.', Text),
+        ],
+        'inserted': [
+            (ins_op, Generic.Inserted, '#push'),
+            (del_op, Generic.Inserted, '#push'),
+            (del_cl, Generic.Inserted, '#pop'),
+
+            (ins_cl, Generic.Inserted, '#pop'),
+            (r'.', Generic.Inserted),
+        ],
+        'deleted': [
+            (del_op, Generic.Deleted, '#push'),
+            (ins_op, Generic.Deleted, '#push'),
+            (ins_cl, Generic.Deleted, '#pop'),
+
+            (del_cl, Generic.Deleted, '#pop'),
+            (r'.', Generic.Deleted),
+        ],
+    }