added mistune as a possible markdown renderer (it's python only)

about.py

-""" This file contains the routines used to compile the 'about' page's text.
-    This text comes to us in three parts, which are stored in three markdown
-    files in the data directory, along with an about_meta.yaml file describing
-    how they are to be described at the top of the page.
+"""
+This file contains the routines used to compile the 'about' page's text.
+This text comes to us in three parts, which are stored in three markdown
+files in the data directory, along with an about_meta.yaml file describing
+how they are to be described at the top of the page.
 
-    The markdown files are then compiled to two pieces of HTML, one for the
-    sidebar and one for the main part of the text, as well as a small
-    dictionary that describes the content of the cards at the top of the page.
+The markdown files are then compiled to two pieces of HTML, one for the
+sidebar and one for the main part of the text, as well as a small
+dictionary that describes the content of the cards at the top of the page.
 
-    Created 16-08-2017 by Josh Borrow (joshua.borrow@durham.ac.uk)
+Created 16-08-2017 by Josh Borrow (joshua.borrow@durham.ac.uk)
 """
 
 #Disable errors associated with un-overwritten methods in HTMLParser.
@@ -15,7 +16,7 @@
 
 from html.parser import HTMLParser
 
-import pypandoc
+from mdcomp import convert_text
 import yaml
 
 
@@ -33,8 +34,8 @@ def compile_markdown(data, data_dir="../data"):
     for item in data["files"]:
         with open(f"{data_dir}/{item['name']}", "r") as handle:
             input_text = handle.read()
-
-        compiled_text = pypandoc.convert_text(input_text, 'html', format='md')
+        
+        compiled_text = convert_text(input_text)
 
         output_text += f"<div id=\"{item['slug']}\">{compiled_text}</div>"
     return output_text

mdcomp.py

+"""
+Allows for us to switch between pandoc and mistune nicely.
+
+If the user does not have pandoc installed, we want to use mistune. The
+problem there is that mistune does not have the automatic id plugin
+for headings that we use to generate sidebars, i.e.
+
+## HEAD
+
+gets converted to
+
+<h2>HEAD</h2>
+
+not
+
+<h2 id="head">HEAD</h2>
+
+like it does within pandoc.
+
+Created 22-09-2017 by Josh Borrow (joshua.borrow@durham.ac.uk)
+"""
+
+try:
+    import pypandoc
+    
+    test = pypandoc.convert_text("hello", "html", format="md")
+
+    def convert_text(input_text):
+        return pypandoc.convert_text(input_text, "html", format="md")
+
+except OSError:
+    print("Pandoc not found on your system. Using mistune (python-only)")
+    import mistune
+
+    class IDRenderer(mistune.Renderer):
+        def header(self, text, level, raw=None):
+            text = "<h{} id={}>{}</h{}>".format(
+                level,
+                (text.replace(" ", "-")).lower(),
+                text,
+                level
+            )
+
+            return text
+
+    renderer = IDRenderer()
+    markdown = mistune.Markdown(renderer=renderer)
+
+    def convert_text(input_text):
+        return markdown(input_text)
+

requirements.txt

 pyyaml
 jinja2
 pypandoc
+mistune