Re: Markdown -> CommonMark extensions tracker

[John MacFarlane <jgm-TVLZxgkOlNX2fBVCVOL8/A@public.gmane.org>]

Note: at this point, we're talking about commonmark extensions
provided by pandoc. None of this is going into the commonmark
spec, which currently just focuses on the core. (Maybe at
some point.)

abbreviations - maybe?

all_symbols_escapable - this is already in core commonmark, so not an extension

angle_brackets_escapable - already in core commonmark

auto_identifiers - we have gfm_auto_identifiers, no plans to
support the old auto_identifiers, since I think it's best to
standardize on one system

backtick_code_blocks - part of core commonmark

blank_before_blockquote - incompatible with core commonmark,
won't be implemented as an extension

blank_before_header -  incompatible with core commonmark,
won't be implemented as an extension

citations - I plan to support this but it's not an easy one to implement

compact_definition_lists - I'd prefer not to support this, for
sake of standardization - it's here for legacy reasons

escaped_line_breaks - part of core commonmark

example_lists - plan to support

fenced_code_attributes - this is provided as part of the
attributes extension, don't plan to implement separately

fenced_code_blocks - part of core commonmark

four_space_rule - don't plan to implement, incompatible with core
commonmark

grid_tables - plan to implement, probably

gutenberg - this only really affects plain output

header_attributes - provided by attributes extension, don't plan
to implement separately

ignore_line_breaks - might make sense to implement, but this
would be a bit tricky to do as a commonmark-hs extension; we
might need a few changes to the core commonmark processor to
enable this.  I'd be curious how many people use it.

inline_code_attributes - provided by attributes, don't plan to
implement separately

inline_notes - will probably implement as an extension

intraword_underscores - part of core commonmark, won't be an extension

latex_macros - not sure, maybe

line_blocks - plan to implement as extensions

link_attributes - provided by attributes extension

lists_without_preceding_blankline - part of core commonmark,
don't plan to implement

literate_haskell - maybe

markdown_attribute - probably not, because commonmark has a
different way of doing this and I'd like to keep it simple

markdown_in_html_blocks - no, because commonmark has a different
way of doing this

mmd_header_identifiers - maybe

mmd_link_attributes - maybe

mmd_title_block - maybe

multiline_tables - plan to implement

native_divs - probably not; I'd prefer to just support the fenced divs

native_spans - ditto, bracketed_spans

old_dashes - probably not, a legacy feature

pandoc_title_block - probably?

shortcut_reference_links - part of core commonmark

simple_tables - plan to support

space_in_atx_header - part of core commonmark, won't be an extension

spaced_reference_links - incompatible with core spec, don't plan
to support

startnum - part of core commonmark

table_captions - plan to support but maybe as part of table extensions

tex_math_double_backslash - not sure; might support

tex_math_single_backslash - incompat with core commonmark
escaping, probably not