Re: How to add to header-includes?

[Albert Krewinkel <albert+pandoc-9EawChwDxG8hFhg+JK9F0w@public.gmane.org>]

oliver <news-WPTjrydoUPgeaOpM6FAJmQkbCANdLtlA@public.gmane.org> writes:

> When I use header-includes: in a metadata-file I can not add more
> header lines to it, neither via document YAML nor via -H <file> on
> the command line. The previous includes are always forgotten.
>
> How can I add header stuff from a file and in the documents YAML?

Bit crude, but here's a Lua filter that can help with this. The
`--include-in-header`/`-H` option must be replaced with `-M
include-in-header=...`, and the default includes must be specified in
the `default-includes` field.


``` lua
-- file: includes.lua
local function ensure_list (x)
  return pandoc.utils.type(x) == 'List' and x or pandoc.List{x}
end

local function read_file (filename)
  return pandoc.RawBlock(FORMAT, io.open(filename, 'rb'):read('a'))
end

function Meta (meta)
  -- Add to header-includes
  meta['header-includes'] = ensure_list(meta['header-includes'])
  meta['header-includes']:extend(ensure_list(meta['default-includes']))
  meta['header-includes']:insert(read_file(meta['include-in-header']))

  -- unset custom include fields
  meta['extra-includes'] = nil
  meta['default-in-header'] = nil

  return meta
end
```

-- 
Albert Krewinkel
GPG: 8eed e3e2 e8c5 6f18 81fe  e836 388d c0b2 1f63 1124