Add breadcrumbs

Likewise, use relative links so that things work when just browsing
files locally without a server.

Next: tweak or remove redundant titles.

6 files changed, 77 insertions, 7 deletions

diff --git a/repo/www/Makefile b/repo/www/Makefile
index 86d1d98..1f32115 100644
--- a/repo/www/Makefile
+++ b/repo/www/Makefile
@@ -14,7 +14,7 @@ page_patterns = $(foreach ext,$(EXTENSIONS),'$(TOP_DIR)/**.$(ext)')
 page_folders = $(call dirnames,$(shell git ls-files $(page_patterns)))
 top_readme = $(shell git ls-files $(addprefix $(TOP_DIR)/README.,$(EXTENSIONS)))
 html_template = template.html
-stylesheets_src =
+stylesheets_src = crumbs.css
 lua_filters = convert-internal-links.lua
 
 all: site
diff --git a/repo/www/crumbs.css b/repo/www/crumbs.css
new file mode 100644
index 0000000..ef42620
--- /dev/null
+++ b/repo/www/crumbs.css
@@ -0,0 +1,31 @@
+nav.breadcrumb ol {
+    padding-left: 0;
+}
+
+nav.breadcrumb li {
+    /* Prefer inline-block to inline, to prevent wrapping inside
+     * individual crumbs. */
+    display: inline-block;
+}
+
+/* Prefer
+ *     li:not(:last-child)::after
+ * to
+ *     li + li::before
+ * as I want crumbs and slashes to wrap like this:
+ *     foo / bar /
+ *     baz
+ * rather than like that:
+ *     foo / bar
+ *     / baz
+ */
+nav.breadcrumb li:not(:last-child)::after {
+    margin-left: 0.25em;
+    height: 0.8em;
+    font-weight: bold;
+    content: '/';
+}
+
+nav.breadcrumb li[aria-current="page"] {
+    font-weight: bold;
+}
diff --git a/repo/www/generate-index.py b/repo/www/generate-index.py
index d615756..a993c41 100755
--- a/repo/www/generate-index.py
+++ b/repo/www/generate-index.py
@@ -10,7 +10,7 @@ from tempfile import NamedTemporaryFile
 
 from git import Repo
 
-from helpers import deserialize_directories, pandoc
+from helpers import deserialize_directories, generate_crumbs, pandoc
 
 
 def parse_arguments():
@@ -102,6 +102,7 @@ def main(arguments):
         path_to_top = '.'
 
     stylesheets = (path.join(path_to_top, s) for s in arguments.css)
+    variables = {'crumbs': generate_crumbs(Path(target)/'index')}
 
     if readme is not None:
         repo_top = Repo(search_parent_directories=True).working_dir
@@ -118,7 +119,8 @@ def main(arguments):
 
             pandoc(readme_path, arguments.output, arguments.template,
                    arguments.filters, stylesheets, title=page_title,
-                   site_title=arguments.site_title, include_after=(toc.name,))
+                   site_title=arguments.site_title, include_after=(toc.name,),
+                   variables=variables)
         return
 
     with NamedTemporaryFile(suffix='.md') as dummy_readme, \
@@ -128,7 +130,8 @@ def main(arguments):
 
         pandoc(dummy_readme.name, arguments.output, arguments.template,
                arguments.filters, stylesheets, title=index_title,
-               site_title=arguments.site_title, include_after=(toc.name,))
+               site_title=arguments.site_title, include_after=(toc.name,),
+               variables=variables)
 
 
 if __name__ == '__main__':
diff --git a/repo/www/generate-page.py b/repo/www/generate-page.py
index e200a9e..8036cc5 100755
--- a/repo/www/generate-page.py
+++ b/repo/www/generate-page.py
@@ -2,10 +2,11 @@
 
 from argparse import ArgumentParser
 from os import path
+from pathlib import Path
 
 from git import Repo
 
-from helpers import pandoc
+from helpers import generate_crumbs, pandoc
 
 
 def parse_arguments():
@@ -41,6 +42,8 @@ def main(arguments):
     path_to_top = path.relpath(repo_top, path.dirname(arguments.page))
     stylesheets = (path.join(path_to_top, s) for s in arguments.css)
 
+    page_path = Path(arguments.page).resolve().relative_to(repo_top)
+
     pandoc(
         arguments.page,
         arguments.output,
@@ -48,7 +51,8 @@ def main(arguments):
         arguments.filters,
         stylesheets,
         title=arguments.title,
-        site_title=arguments.site_title
+        site_title=arguments.site_title,
+        variables={'crumbs': generate_crumbs(page_path)}
     )
 
 
diff --git a/repo/www/helpers.py b/repo/www/helpers.py
index 9b97902..80b8857 100644
--- a/repo/www/helpers.py
+++ b/repo/www/helpers.py
@@ -57,7 +57,7 @@ def deserialize_directories(directories):
 
 
 def pandoc(page, output, template, filters, stylesheets, title=None,
-           site_title=None, include_after=()):
+           site_title=None, include_after=(), variables=None):
     cmd = (
         'pandoc', '-s', page, '-o', output, '--template', template,
         *chain(*(('--lua-filter', f) for f in filters)),
@@ -69,6 +69,33 @@ def pandoc(page, output, template, filters, stylesheets, title=None,
         cmd += ('-M', f'title={title}')
     if site_title is not None:
         cmd += ('-T', site_title)
+    if variables is not None:
+        cmd += tuple(chain(
+            *(('-V', f'{k}={v}') for k, v in variables.items())
+        ))
 
     environ['LUA_PATH'] = '.cache/?.lua;;'
     run(cmd, check=True)
+
+
+def generate_crumbs(target):
+    parts = ('(top)', *target.parts)
+
+    if parts[-1] == 'index':
+        *crumbs, current = parts[:-1]
+    else:
+        crumbs = parts[:-1]
+        current, _ = path.splitext(parts[-1])
+
+    crumbs_li = (
+        '<li><a href="{link}">{crumb}</a></li>'.format(
+            link=(path.relpath(path.join(*crumbs[1:i], 'index.html'),
+                               start=target.parent)),
+            crumb=crumb
+        )
+        for i, crumb in enumerate(crumbs, start=1)
+    )
+
+    current_li = f'<li aria-current="page">{current}</li>'
+
+    return '\n'.join((*crumbs_li, current_li))
diff --git a/repo/www/template.html b/repo/www/template.html
index 724cde4..f2b308d 100644
--- a/repo/www/template.html
+++ b/repo/www/template.html
@@ -33,6 +33,11 @@ $include-before$
 $endfor$
 $if(title)$
 <header id="title-block-header">
+<nav class="breadcrumb" aria-label="Breadcrumb">
+<ol>
+$crumbs$
+</ol>
+</nav>
 <h1 class="title">$title$</h1>
 $if(subtitle)$
 <p class="subtitle">$subtitle$</p>