pydot: handle multiple dot images in one file

incorporealcms/mdx/pydot.py

@@ -25,9 +25,12 @@ class InlinePydotPreprocessor(markdown.preprocessors.Preprocessor):
     def run(self, lines):
         """Match and generate diagrams from dot code blocks."""
         text = '\n'.join(lines)
-        for match in self.BLOCK_RE.finditer(text):
-            filename = match.group(1)
-            dot_string = match.group(2)
+        out = text
+        for block_match in self.BLOCK_RE.finditer(text):
+            filename = block_match.group(1)
+            dot_string = block_match.group(2)
+            logger.debug("matched markdown block: %s", dot_string)
+            logger.debug("match start/end: %s/%s", block_match.start(), block_match.end())
 
             # use pydot to turn the text into pydot
             graphs = pydot.graph_from_dot_data(dot_string)
@@ -41,9 +44,9 @@ class InlinePydotPreprocessor(markdown.preprocessors.Preprocessor):
             inline_image = f'![{filename}]({data_path})'
 
             # replace the image in the output markdown
-            text = f'{text[:match.start()]}\n{inline_image}\n{text[match.end():]}'
+            out = out.replace(block_match.group(0), inline_image)
 
-        return text.split('\n')
+        return out.split('\n')
 
 
 def makeExtension(*args, **kwargs):