An optional pre-processor function that receives the
metadata, input_file, runtime, knit_meta,
and files_dir and can return additional arguments to pass to pandoc.
post_processor
An optional post-processor function that receives the
metadata, input_file, output_file, clean,
and verbose parmaeters, and can return an alternative
output_file.
base_format
An optional format to extend.
Value
An R Markdown output format definition that can be passed to
render.