Utility to output valid internal anchors

bin/anchors.awk

@@ -0,0 +1,35 @@
+#!/usr/bin/gawk -f
+
+# Output all eligible anchors in the document
+
+BEGIN {
+    # /contents is OK as a page, but will not be picked up automatically
+    print "/contents"
+    name = ""
+}
+
+/(^# |^## |^### ).* <!-- .* -->$/ {
+    path = gensub(/^#+ .* <!-- ([^*]+).? -->$/, "\\1", "1")
+    print path
+}
+
+# Headings
+/^#/ {
+    if ($0 ~ / <!-- .* -->$/) {
+        name = gensub(/^#+ (.*) <!-- .* -->$/, "\\1", "1")
+    } else {
+        name = gensub(/^#+ (.*)$/, "\\1", "1")
+    }
+    name = tolower(name)
+    gsub(/ /, "-", name)
+    gsub(/[^a-z0-9_-]/, "", name)
+
+    print path "#" name
+}
+
+# Explicit anchors - only one per line allowed, at the start of the line
+/^<a id=".*"><\/a>$/ {
+    name = gensub(/^<a id="(.*)"><\/a>$/, "\\1", "1")
+    print path "#" name
+}
+