themes/docsy/layouts/shortcodes/tabpane.html

<!-- Scratchpad gets populated through call to .Inner -->  
{{- .Inner -}}

<ul class="nav nav-tabs" id="tabs-{{- $.Ordinal -}}" role="tablist">
  {{- range $index, $element := $.Scratch.Get "tabs" -}}
    <li class="nav-item">
      <!-- Generate the IDs for the <a> and the <div> elements -->
      {{- $tabid := printf "tabs-%v-%v-tab" $.Ordinal $index | anchorize -}}
      {{- $entryid := printf "tabs-%v-%v" $.Ordinal $index | anchorize -}}
      <!-- Replace space and + from tabname to set class -->
      {{- $tabname := replaceRE "(\\s)" "-" $element.header -}}
      {{- $tabname := replaceRE "(\\+)" "-" $tabname -}}
      <a class="nav-link{{ if eq $index "0" }} active{{ end }} tab-{{ $tabname }}"
        id="{{ $tabid }}" data-toggle="tab" href="#{{ $entryid }}" role="tab" onclick="handleClick({{ $tabname }});"
        aria-controls="{{ $entryid }}" aria-selected="{{- cond (eq $index "0") "true" "false" -}}">
        {{ index . "header" }}
      </a>
    </li>
  {{- end -}}
</ul>

<!-- Inner content -->
<div class="tab-content" id="tabs-{{- $.Ordinal -}}-content">
  {{- range $index, $element := $.Scratch.Get "tabs" -}}

    {{- $lang := default $.Site.Language.Lang ($.Get "lang") -}}
    {{with $.Get "langEqualsHeader"}}
        {{ if $.Get "langEqualsHeader"}}
          {{ $lang = $element.header }}
        {{end}}
    {{end}}
    {{- $hloptions := default "" ($.Get "highlight") -}}
    {{- with $element.language -}}
      {{  $lang = $element.language }}
    {{- end -}}
    {{- with $element.highlight -}}
      {{  $hloptions = $element.highlight }}
    {{- end -}}
    {{- $tabid := printf "tabs-%v-%v-tab" $.Ordinal $index | anchorize -}}
    {{- $entryid := printf "tabs-%v-%v" $.Ordinal $index | anchorize -}}
    <div class="tab-pane fade{{ if eq $index "0" }} show active{{ end }}"
        id="{{ $entryid }}" role="tabpanel" aria-labelled-by="{{ $tabid }}">
      {{- highlight (index . "content") $lang $hloptions -}}
    </div>
  {{ end }}
</div>