Add ABC for writers

3 files changed, 37 insertions, 2 deletions

diff --git a/mammoth/writers/abc.py b/mammoth/writers/abc.py
new file mode 100644
index 0000000..a4a648b
--- /dev/null
+++ b/mammoth/writers/abc.py
@@ -0,0 +1,31 @@
+from __future__ import absolute_import
+
+import abc
+
+
+class Writer(object):
+    __metaclass__ = abc.ABCMeta
+    
+    @abc.abstractmethod
+    def text(self, text):
+        pass
+    
+    @abc.abstractmethod
+    def start(self, name, attributes=None):
+        pass
+
+    @abc.abstractmethod
+    def end(self, name):
+        pass
+    
+    @abc.abstractmethod
+    def self_closing(self, name, attributes=None):
+        pass
+    
+    @abc.abstractmethod
+    def append(self, html):
+        pass
+    
+    @abc.abstractmethod
+    def as_string(self):
+        pass
diff --git a/mammoth/writers/html.py b/mammoth/writers/html.py
index cf936cd..7e6ca95 100644
--- a/mammoth/writers/html.py
+++ b/mammoth/writers/html.py
@@ -1,9 +1,11 @@
 from __future__ import unicode_literals
 
+from .abc import Writer
+
 import cgi
 
 
-class HtmlWriter(object):
+class HtmlWriter(Writer):
     def __init__(self):
         self._fragments = []
     
diff --git a/mammoth/writers/markdown.py b/mammoth/writers/markdown.py
index c291479..6cd9cd0 100644
--- a/mammoth/writers/markdown.py
+++ b/mammoth/writers/markdown.py
@@ -1,5 +1,7 @@
 from __future__ import unicode_literals
 
+from .abc import Writer
+
 import re
 
 
@@ -149,7 +151,7 @@ def _default_writer(attributes, markdown_state):
     return _default_output
 
 
-class MarkdownWriter(object):
+class MarkdownWriter(Writer):
     def __init__(self):
         self._fragments = []
         self._element_stack = []