{{ $.Scratch.Set "bl_author" false }}

{{ if .IsNamedParams }}
  {{ $.Scratch.Set "bl_author" (.Get "author") }}
{{ end }}

<blockquote>
  {{ .Inner | markdownify }}
  <span>̶ &nbsp;{{ with $.Scratch.Get "bl_author" }}{{ . }}{{ end }}.</span>
</blockquote>