@top Document { heading line* }

heading { Heading? "\n" }
line    { Indent* ((AutoLink | word) space*)* "\n" }

@tokens {
  space       { $[ \t] }
  letter      { ![ \t\n] }
  word        { letter+ }
  Heading     { (letter | space)+ }
  Indent      { space }
  AutoLink    { ("http" | "https") "://" word }
  @precedence { AutoLink, word }
}