Include Code Samples Files

Your files:

include-code-block.lua
docs/
    my-file.md
    code-samples/
        Foo.hx

In my-file.md:

Hi.

~~~{.haxe include=code-samples/Foo.hx}
~~~

Bye.

In include-code-block.lua:

function CodeBlock (cb)
    if cb.attributes.include then
        -- read file
        local fh = io.open(cb.attributes.include)
        local content = fh:read('*a')
        fh:close()
        -- remove key-value pair for key "include"
        cb.attributes.include = nil
        -- return final code block
        return pandoc.CodeBlock(content, cb.attr)
    end
end

Then, from within the docs directory, process like so:

pandoc -s -o my-file.html --lua-filter=../include-code-block.lua my-file.md