kramdown を使って Markdown を AST に変換する

kramdown を使用することで Markdown を AST に変換することが出来ます。

require "pp"
require "kramdown"

code =<<-MKD
# title

hello world

- list1
- list2
MKD

doc = Kramdown::Document.new(code, input: "GFM")
result = doc.to_hash_ast

pp result

出力結果

{:type=>:root,
 :options=>
  {:encoding=>#<Encoding:UTF-8>,
   :location=>1,
   :options=>{},
   :abbrev_defs=>{},
   :abbrev_attr=>{}},
 :children=>
  [{:type=>:header,
    :attr=>{"id"=>"title"},
    :options=>{:level=>1, :raw_text=>"title", :location=>1},
    :children=>[{:type=>:text, :value=>"title", :options=>{:location=>1}}]},
   {:type=>:blank, :value=>"\n"},
   {:type=>:p,
    :options=>{:location=>3},
    :children=>
     [{:type=>:text, :value=>"hello world", :options=>{:location=>3}}]},
   {:type=>:blank, :value=>"\n"},
   {:type=>:ul,
    :options=>{:location=>5},
    :children=>
     [{:type=>:li,
       :options=>{:location=>5},
       :children=>
        [{:type=>:p,
          :options=>{:location=>5, :transparent=>true},
          :children=>
           [{:type=>:text, :value=>"list1", :options=>{:location=>5}}]}]},
      {:type=>:li,
       :options=>{:location=>6},
       :children=>
        [{:type=>:p,
          :options=>{:location=>6, :transparent=>true},
          :children=>
           [{:type=>:text, :value=>"list2", :options=>{:location=>6}}]}]}]}]}

kramdown のバージョンが 1.14.0 未満の場合は #to_hash_ast が使用できないので下記のコードを使用します。(kramdown issue#435)

- result = doc.to_hash_ast
+ result, warnings = Kramdown::Converter::HashAST.convert(doc.root, doc.options)