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require 'ffi'
require 'stringio'
require 'cgi'
module CMark
extend FFI::Library
ffi_lib ['libcmark', 'cmark']
typedef :pointer, :node
enum :node_type, [:document, :blockquote, :list, :list_item,
:fenced_code, :indented_code, :html, :paragraph,
:atx_header, :setext_header, :hrule, :reference_def,
:str, :softbreak, :linebreak, :code, :inline_html,
:emph, :strong, :link, :image]
attach_function :cmark_free_nodes, [:node], :void
attach_function :cmark_node_unlink, [:node], :void
attach_function :cmark_markdown_to_html, [:string, :int], :string
attach_function :cmark_parse_document, [:string, :int], :node
attach_function :cmark_node_first_child, [:node], :node
attach_function :cmark_node_parent, [:node], :node
attach_function :cmark_node_next, [:node], :node
attach_function :cmark_node_previous, [:node], :node
attach_function :cmark_node_get_type, [:node], :node_type
attach_function :cmark_node_get_string_content, [:node], :string
attach_function :cmark_node_get_header_level, [:node], :int
end
class Node
attr_accessor :type, :children, :string_content, :header_level
def initialize(pointer)
if pointer.null?
return nil
end
@pointer = pointer
@type = CMark::cmark_node_get_type(pointer)
@children = []
first_child = CMark::cmark_node_first_child(pointer)
b = first_child
while !b.null?
@children << Node.new(b)
b = CMark::cmark_node_next(b)
end
@string_content = CMark::cmark_node_get_string_content(pointer)
@header_level = CMark::cmark_node_get_header_level(pointer)
if @type == :document
self.free
end
end
def self.from_markdown(s)
len = s.bytes.length
Node.new(CMark::cmark_parse_document(s, len))
end
def free
CMark::cmark_free_nodes(@pointer)
end
end
class Renderer
def initialize(stream = nil)
if stream
@stream = stream
@stringwriter = false
else
@stringwriter = true
@stream = StringIO.new
end
@need_blocksep = false
end
def outf(format, *args)
@stream.printf(format, *args)
end
def out(arg)
@stream.write(arg)
end
def render(node)
if node.kind_of?(Array)
node.each { |x| self.render(x) }
else
case node.type
when :document
self.document(node.children)
if @stringwriter
return @stream.string
end
when :paragraph
self.blocksep
self.paragraph(node.children)
@need_blocksep = true
when :setext_header, :atx_header
self.blocksep
self.header(node.header_level, node.children)
@need_blocksep = true
when :str
self.str(node.string_content)
else
# raise "unimplemented " + node.type.to_s
end
@last_node = node.type
end
end
def blocksep
if @need_blocksep
self.out("\n\n")
end
end
def document(children)
self.render(children)
end
def header(level, children)
self.render(children)
end
def paragraph(children)
self.render(children)
end
def str(content)
self.out(content)
end
end
class HtmlRenderer < Renderer
def header(level, children)
self.outf("<h%d>", level)
self.render(children)
self.outf("</h%d>", level)
end
def paragraph(children)
self.out("<p>")
self.render(children)
self.out("</p>")
end
def str(content)
self.out(CGI.escapeHTML(content))
end
end
doc = Node.from_markdown(STDIN.read())
renderer = HtmlRenderer.new(STDOUT)
renderer.render(doc)
# def markdown_to_html(s)
# len = s.bytes.length
# CMark::cmark_markdown_to_html(s, len)
# end
# print markdown_to_html(STDIN.read())
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