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#!/usr/bin/env ruby
require 'ffi'
require 'stringio'
require 'cgi'
require 'set'
require 'uri'
module CMark
extend FFI::Library
ffi_lib ['libcmark', 'cmark']
typedef :pointer, :node
enum :node_type, [:document, :blockquote, :list, :list_item,
:code_block, :html, :paragraph,
:header, :hrule, :reference_def,
:str, :softbreak, :linebreak, :code, :inline_html,
:emph, :strong, :link, :image]
enum :list_type, [:no_list, :bullet_list, :ordered_list]
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_url, [:node], :string
attach_function :cmark_node_get_title, [:node], :string
attach_function :cmark_node_get_header_level, [:node], :int
attach_function :cmark_node_get_list_type, [:node], :list_type
attach_function :cmark_node_get_list_start, [:node], :int
attach_function :cmark_node_get_list_tight, [:node], :bool
end
class Node
attr_accessor :type, :children, :parent, :string_content, :header_level,
:list_type, :list_start, :list_tight, :url, :title
def initialize(pointer)
if pointer.null?
return nil
end
@pointer = pointer
@type = CMark::cmark_node_get_type(pointer)
@children = []
@parent = nil
first_child = CMark::cmark_node_first_child(pointer)
b = first_child
while !b.null?
child = Node.new(b)
child.parent = self
@children << child
b = CMark::cmark_node_next(b)
end
@string_content = CMark::cmark_node_get_string_content(pointer)
if @type == :header
@header_level = CMark::cmark_node_get_header_level(pointer)
end
if @type == :list
@list_type = CMark::cmark_node_get_list_type(pointer)
@list_start = CMark::cmark_node_get_list_start(pointer)
@list_tight = CMark::cmark_node_get_list_tight(pointer)
end
if @type == :link || @type == :image
@url = CMark::cmark_node_get_url(pointer)
if !@url then @url = "" end
@title = CMark::cmark_node_get_title(pointer)
if !@title then @title = "" end
end
if @type == :document
self.free
end
end
# An iterator that "walks the tree," returning each node
def walk(&blk)
yield self
self.children.each do |child|
child.walk(&blk)
end
end
# Walk the tree and transform it. blk should take one argument,
# a node. If its value is a node, that node replaces the node being
# visited. If its value is an array of nodes, those nodes are spliced
# in place of the node being visited (so, to delete a node, use an
# empty array). Otherwise the node is left as it is.
def transform(&blk)
self.walk do |node|
skip = false
res = blk.call(node)
if res.kind_of?(Array)
splice = res
elsif res.kind_of?(Node)
splice = [res]
else
skip = true
end
unless skip
parent = node.parent
if parent
siblings = node.parent.children
index = siblings.index(node)
siblings.replace(siblings.slice(0,index) + splice +
siblings.slice(index + 1, siblings.length))
else # at the document root, just skip
end
end
end
end
def self.parse_string(s)
Node.new(CMark::cmark_parse_document(s, s.bytesize))
end
def self.parse_file(f)
s = f.read()
self.parse_string(s)
end
protected
def free
CMark::cmark_free_nodes(@pointer)
end
end
class Renderer
attr_accessor :in_tight, :warnings, :in_plain
def initialize(stream = nil)
if stream
@stream = stream
@stringwriter = false
else
@stringwriter = true
@stream = StringIO.new
end
@need_blocksep = false
@warnings = Set.new []
@in_tight = false
@in_plain = false
end
def outf(format, *args)
@stream.printf(format, *args)
end
def out(*args)
args.each do |arg|
if arg.kind_of?(String)
@stream.write(arg)
elsif arg.kind_of?(Node)
self.render(arg)
elsif arg.kind_of?(Array)
arg.each { |x| self.out(x) }
else
@stream.write(arg)
end
end
end
def render(node)
@node = node
if node.type == :document
self.document(node)
self.out("\n")
if @stringwriter
return @stream.string
end
elsif self.in_plain && node.type != :str && node.type != :softbreak
# pass through looking for str, softbreak
node.children.each do |child|
render(child)
end
else
begin
self.send(node.type, node)
rescue NoMethodError => e
@warnings.add("WARNING: " + node.type.to_s + " not implemented.")
raise e
end
end
end
def document(node)
self.out(node.children)
end
def code_block(node)
self.code_block(node)
end
def reference_def(node)
end
def blocksep
self.out("\n")
end
def containersep
if !self.in_tight
self.out("\n")
end
end
def block(&blk)
if @need_blocksep
self.blocksep
end
blk.call
@need_blocksep = true
end
def container(starter, ender, &blk)
self.out(starter)
self.containersep
@need_blocksep = false
blk.call
self.containersep
self.out(ender)
end
def plain(&blk)
old_in_plain = @in_plain
@in_plain = true
blk.call
@in_plain = old_in_plain
end
end
class HtmlRenderer < Renderer
def header(node)
block do
self.out("<h", node.header_level, ">", node.children,
"</h", node.header_level, ">")
end
end
def paragraph(node)
block do
if self.in_tight
self.out(node.children)
else
self.out("<p>", node.children, "</p>")
end
end
end
def list(node)
old_in_tight = self.in_tight
self.in_tight = node.list_tight
block do
if node.list_type == :bullet_list
container("<ul>", "</ul>") do
self.out(node.children)
end
else
start = node.list_start == 1 ? '' :
(' start="' + node.list_start.to_s + '"')
container(start, "</ol>") do
self.out(node.children)
end
end
end
self.in_tight = old_in_tight
end
def list_item(node)
block do
container("<li>", "</li>") do
self.out(node.children)
end
end
end
def blockquote(node)
block do
container("<blockquote>", "</blockquote>") do
self.out(node.children)
end
end
end
def hrule(node)
block do
self.out("<hr />")
end
end
def code_block(node)
block do
self.out("<pre><code>")
self.out(CGI.escapeHTML(node.string_content))
self.out("</code></pre>")
end
end
def html(node)
block do
self.out(node.string_content)
end
end
def inline_html(node)
self.out(node.string_content)
end
def emph(node)
self.out("<em>", node.children, "</em>")
end
def strong(node)
self.out("<strong>", node.children, "</strong>")
end
def link(node)
self.out('<a href="', URI.escape(node.url), '"')
if node.title && node.title.length > 0
self.out(' title="', CGI.escapeHTML(node.title), '"')
end
self.out('>', node.children, '</a>')
end
def image(node)
self.out('<img src="', URI.escape(node.url), '"')
if node.title && node.title.length > 0
self.out(' title="', CGI.escapeHTML(node.title), '"')
end
plain do
self.out(' alt="', node.children, '" />')
end
end
def str(node)
self.out(CGI.escapeHTML(node.string_content))
end
def code(node)
self.out("<code>")
self.out(CGI.escapeHTML(node.string_content))
self.out("</code>")
end
def linebreak(node)
self.out("<br/>")
self.softbreak(node)
end
def softbreak(node)
self.out("\n")
end
end
doc = Node.parse_file(ARGF)
# Walk tree and print URLs for links
doc.walk do |node|
if node.type == :link
printf("URL = %s\n", node.url)
end
end
# Capitalize strings in headers
doc.walk do |node|
if node.type == :header
node.walk do |subnode|
if subnode.type == :str
subnode.string_content = subnode.string_content.upcase
end
end
end
end
# Walk tree and transform links to regular text
doc.transform do |node|
if node.type == :link
node.children
end
end
renderer = HtmlRenderer.new(STDOUT)
renderer.render(doc)
renderer.warnings.each do |w|
STDERR.write(w)
STDERR.write("\n")
end
# 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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