frontmatter fix about 'created' field

_src/build.py

@@ -9,6 +9,7 @@ import sys
 import configparser
 from fnmatch import fnmatch
 import frontmatter # from package python-frontmatter
+import datetime
 
 def link_this(src: str, dest: str):
     """Creates symlink to source at destination
@@ -109,7 +110,14 @@ if __name__ == '__main__':
         
         # load content file
         with open('content/'+path) as fp:
-            content_data = fp.read()
+            frontmatter_data, content = frontmatter.parse(fp.read())
+        
+        if 'created' in frontmatter_data:
+            # frontmatter produces date objects if created field is in format yyyy-mm-dd
+            # if it contains time as in ISO 8601, we want to convert it to datetime
+            # https://en.wikipedia.org/wiki/ISO_8601
+            if type(frontmatter_data['created']) == str:
+                frontmatter_data['created'] = datetime.datetime.fromisoformat(frontmatter_data['created'])
         
         # load template
         if template := template_for(path):