Deprecated in favor of cmark-lua

This is a lua binding to the libcmark commonmark parser (https://github.com/jgm/CommonMark). It requires that libcmark be installed, and it also requires luajit.

This is work in progress. The idea is to use libcmark to do the parsing, and provide pure lua writers and lua hooks for AST manipulation. This way authors can easily customize the way their text is rendered, and create renderers for new formats.

So far we have an xml writer (which prints an XML serialization of the AST) and an html writer (which passes the CommonMark spec tests).

Writers can easily be customized. For example, suppose you want to render all regular text content uppercase, leaving code and HTML tags alone:

#!/usr/bin/env luajit
local cmark = require("commonmark")
local W = require("commonmark.writer.html")
local inp = io.read("*all")
local doc = cmark.parse_document(inp, string.len(inp))
writer = W.new()
-- customize the writer:
writer.text = function(node)
   local s = cmark.node_get_string_content(node)
   writer.out(writer.escape(s:upper()))
end
io.write(writer.render(doc))
for warning in writer.warnings() do
   print('WARNING', warning)
end

Alternatively, you could walk the AST, changing text content to uppercase, and use the faster libcmark HTML renderer:

#!/usr/bin/env luajit
local cmark = require("commonmark")
local W = require("commonmark.writer.html")
local inp = io.read("*all")
local doc = cmark.parse_document(inp, string.len(inp))
for node in cmark.walk(doc) do
   if cmark.node_type(node) == 'text' then
      cmark.node_set_string_content(node, cmark.node_get_string_content(node):upper())
   end
end
io.write(cmark.render_html(doc))

No doubt the interface can be improved, but this is a start.