Add navigation consistency checking script

tools/navigation.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+import os
+import glob
+import yaml
+
+
+def get_all_pages():
+  return [file for file in glob.glob("gdb/*.md")
+          if not file.endswith("/index.md")]
+
+
+def fix_web_path(page):
+  return '/' + page[:-3]
+
+
+def parse_page_data(page):
+  with open(page) as fd:
+    return next(yaml.safe_load_all(fd))
+
+
+def most_appropriate_title(data):
+  return data.get("linkTitle") or data['title']
+
+
+def traverse_siblings(pages, start, sibling='next'):
+  page = start
+  while page in pages:
+    yield page
+    page = pages[page]['siblings'].get(sibling)
+
+
+def create_intro_toc(pages, start, offset=2):
+  for num, page in enumerate(traverse_siblings(pages, start)):
+    data = pages[page]
+    title = most_appropriate_title(data)
+    print(f"{num + offset}. [{title}]({page})\n")
+
+
+def create_navbar(pages, start):
+  longest_link = max(map(len, traverse_siblings(pages, start))) + 2
+
+  for page in traverse_siblings(pages, start):
+    data = pages[page]
+    title = most_appropriate_title(data)
+    linksq = f"'{page}'"
+    linkdq = f'"{page}"'
+    print(f'    <a href={linkdq:{longest_link}s} class="{{{{#is meta.url {linksq:{longest_link}s}}}}}active {{{{/is}}}}dropdown-item">{title}</a>')
+
+
+def check_nav_consistency(pages, first):
+  for page in traverse_siblings(pages, first):
+    siblings = pages[page]['siblings']
+    for sibling in 'prev', 'next':
+      sibling_data = pages.get(siblings.get(sibling))
+      if sibling_data:
+        sibling_title = most_appropriate_title(sibling_data)
+        link_title = siblings[sibling + 'Caption']
+        if sibling_title != link_title:
+          print(f"{page}: caption mismatch for {sibling}: expected {sibling_title!r}, got {link_title!r}")
+
+
+def main():
+  os.chdir("../public")
+  pages = {fix_web_path(file): parse_page_data(file) for file in get_all_pages()}
+  *_, first = traverse_siblings(pages, next(iter(pages)), sibling="prev")
+  create_intro_toc(pages, first)
+  create_navbar(pages, first)
+  check_nav_consistency(pages, first)
+  return 0
+
+
+if __name__ == '__main__':
+  main()