toc: add toc partial [newer impl]

* gets toc fixed

Signed-off-by: Aditya Telange <21258296+adityatelange@users.noreply.github.com>

layouts/partials/toc.html

@@ -0,0 +1,84 @@
+{{- $headers := findRE "<h[1-4].*?>(.|\n])+?</h[1-4]>" .Content -}}
+{{- $has_headers := ge (len $headers) 1 -}}
+{{- if $has_headers -}}
+
+{{- $largest := 6 -}}
+{{- range $headers -}}
+{{- $headerLevel := index (findRE "[1-4]" . 1) 0 -}}
+{{- $headerLevel := len (seq $headerLevel) -}}
+{{- if lt $headerLevel $largest -}}
+{{- $largest = $headerLevel -}}
+{{- end -}}
+{{- end -}}
+
+{{- $firstHeaderLevel := len (seq (index (findRE "[1-4]" (index $headers 0) 1) 0)) -}}
+
+{{- $.Scratch.Set "bareul" slice -}}
+<ul>
+    {{- range seq (sub $firstHeaderLevel $largest) -}}
+    <ul>
+        {{- $.Scratch.Add "bareul" (sub (add $largest .) 1) -}}
+        {{- end -}}
+        {{- range $i, $header := $headers -}}
+        {{- $headerLevel := index (findRE "[1-4]" . 1) 0 -}}
+        {{- $headerLevel := len (seq $headerLevel) -}}
+
+        {{/* get id="xyz" */}}
+        {{ $id := index (findRE "(id=\"(.*?)\")" $header 9) 0 }}
+
+        {{/* strip id="" to leave xyz (no way to get regex capturing groups in hugo :( */}}
+        {{ $cleanedID := replace (replace $id "id=\"" "") "\"" "" }}
+        {{- $header := replaceRE "<h[1-4].*?>((.|\n])+?)</h[1-4]>" "$1" $header -}}
+
+        {{- if ne $i 0 -}}
+        {{- $prevHeaderLevel := index (findRE "[1-4]" (index $headers (sub $i 1)) 1) 0 -}}
+        {{- $prevHeaderLevel := len (seq $prevHeaderLevel) -}}
+        {{- if gt $headerLevel $prevHeaderLevel -}}
+        {{- range seq $prevHeaderLevel (sub $headerLevel 1) -}}
+        <ul>
+            {{/* the first should not be recorded */}}
+            {{- if ne $prevHeaderLevel . -}}
+            {{- $.Scratch.Add "bareul" . -}}
+            {{- end -}}
+            {{- end -}}
+            {{- else -}}
+            </li>
+            {{- if lt $headerLevel $prevHeaderLevel -}}
+            {{- range seq (sub $prevHeaderLevel 1) -1 $headerLevel -}}
+            {{- if in ($.Scratch.Get "bareul") . -}}
+        </ul>
+        {{/* manually do pop item */}}
+        {{- $tmp := $.Scratch.Get "bareul" -}}
+        {{- $.Scratch.Delete "bareul" -}}
+        {{- $.Scratch.Set "bareul" slice}}
+        {{- range seq (sub (len $tmp) 1) -}}
+        {{- $.Scratch.Add "bareul" (index $tmp (sub . 1)) -}}
+        {{- end -}}
+        {{- else -}}
+    </ul>
+    </li>
+    {{- end -}}
+    {{- end -}}
+    {{- end -}}
+    {{- end -}}
+    <li>
+        <a href="#{{- $cleanedID  -}}">{{- $header | safeHTML -}}</a>
+        {{- else -}}
+    <li>
+        <a href="#{{- $cleanedID -}}">{{- $header | safeHTML -}}</a>
+        {{- end -}}
+        {{- end -}}
+        <!-- {{- $firstHeaderLevel := len (seq (index (findRE "[1-4]" (index $headers 0) 1) 0)) -}} -->
+        {{ $firstHeaderLevel := $largest }}
+        {{- $lastHeaderLevel := len (seq (index (findRE "[1-4]" (index $headers (sub (len $headers) 1)) 1) 0)) -}}
+    </li>
+    {{- range seq (sub $lastHeaderLevel $firstHeaderLevel) -}}
+    {{- if in ($.Scratch.Get "bareul") (add . $firstHeaderLevel) -}}
+</ul>
+{{- else -}}
+</ul>
+</li>
+{{- end -}}
+{{- end -}}
+</ul>
+{{- end -}}