regionInclude.html

{{/*
  snippet.html
  Usage:
    {{< regionInclude "filename.md" "region_name" >}}
    {{< regionInclude "filename.python" "region_name" "python" >}}
*/}}

{{ $file := .Get 0 }}
{{ $region := .Get 1 }}
{{ $lang := .Get 2 | default "text" }}
{{ $path := printf "%s%s" .Page.File.Dir $file }}

{{ if or (not $file) (eq $file "") }}
  {{ errorf "The file parameter (first argument) is required and must be non-empty in %s" .Page.File.Path }}
{{ end }}
{{ if or (not $region) (eq $region "") }}
  {{ errorf "The region parameter (second argument) is required and must be non-empty in %s" .Page.File.Path }}
{{ end }}
{{ if not (fileExists $path) }}
  {{ errorf "File %q not found (referenced in %s)" $path .Page.File.Path }}
{{ end }}

{{ $content := readFile $path | replaceRE "\r\n" "\n" }}
{{ $start_tag := printf "[START %s]" $region }}
{{ $end_tag := printf "[END %s]" $region }}

{{ $lines := slice }}
{{ $in_snippet := false }}
{{ range split $content "\n" }}
  {{ if $in_snippet }}
    {{ if in . $end_tag }}
      {{ $in_snippet = false }}
    {{ else }}
      {{ $lines = $lines | append . }}
    {{ end }}
  {{ else if in . $start_tag }}
    {{ $in_snippet = true }}
  {{ end }}
{{ end }}

{{ $snippet := delimit $lines "\n" }}

{{ if eq (trim $snippet "") "" }}
  {{ errorf "Region %q not found or empty in file %s (referenced in %s)" $region $file .Page.File.Path }}
{{ end }}

{{ if eq $lang "text" }}
  {{ $snippet | markdownify }}
{{ else }}
```{{ $lang }}
{{ $snippet | safeHTML }}
```
{{ end }}