{%- comment -%}
  Resolves a per-surface toggle into `surface_enabled` (true / false).

  Usage:
    include surface-enabled.html config=site.right_sidebar.pins.enable
    ... then test `surface_enabled`

  The config value may be either form:

    enable: true              -> shown everywhere; any per-surface values are
                                 irrelevant because there are none to read
    enable: false             -> hidden everywhere
    enable:                   -> resolved per surface, via page-kind.html
      homepage: true
      posts: false
      tabs: true
      other_pages: false

  The boolean shorthand is checked first, so `enable: true` short-circuits and
  never looks at the surfaces. When the value is a boolean, indexing it yields
  nothing, which is why `enable: false` also lands on hidden.

  NB: no literal Liquid tags in this comment -- a comment block still tokenises
  the tags inside it, so an argument-less tag here is a parse error.
{%- endcomment -%}
{%- include page-kind.html -%}
{%- if include.config == true -%}
  {%- assign surface_enabled = true -%}
{%- else -%}
  {%- assign surface_enabled = include.config[page_kind] -%}
{%- endif -%}