markdown用peg

README.md

ここにアクセスして 左の入力欄にpegの内容をコピペすれば動きます。

スライド：何となく勉強した気分になれるパーサ入門
上記スライドに感謝。

markdonw.peg

start = doc
doc = block:block+ { 
  return block;
}
block = list / line / code / heading / blankline / sentence

list = l:(whitespace "* " chars blankline?)+ {
  return {
    type:"list",
    list: l.map(function(list){return list[2];})
  };
}
line = "---" "-"* blankline? {return {type:"line"}}
//link = ! {false}
//image = ! {false}
//quotation = ! {false}

heading = prefix:"#"+ " " text:text { 
  return {
  	type:"heading",
    text:text
  }
}

sentence = text:text {
  return {type:"sentence",text:text}
}


code = "```" lang:chars? text:code_content "```" blankline? {
  return {
    type:"code",
    lang:lang||"",
  	text:text.trim()
  };
}

text = t:chars blankline?  {
  return t;
}
code_content=
  $(nobackchars "`" code_content)
  / $(nobackchars "``" code_content)
  / $nobackchars
  
blankline = [\n] { return {type:"blank"}; }

chars = $[^\n]+
nobackchars = $[^`]+
whitespace=[ \t\n\r]*