class BlockParser

  preclow
    nonassoc DUMMY
    left     ITEMLISTLINE
             ENUMLISTLINE
             DESCLISTLINE
             METHODLISTLINE
             STRINGLINE
  prechigh

  token STRINGLINE
        ITEMLISTLINE
        ENUMLISTLINE
        DESCLISTLINE
        METHODLISTLINE
        WHITELINE
        SUBTREE
        HEADLINE
        INCLUDE
        INDENT
        DEDENT
        DUMMY

  rule
    document : blocks { result = RDoc::Markup::Document.new(*val[0]) }
             |        { raise ParseError, "file empty" }
             ;

    blocks : blocks block { result = val[0].concat val[1] }
           | block        { result = val[0] }
           ;

    block : textblock { result = val }
          | verbatim  { result = val }
          | lists
          | headline  { result = val }
          | include   { result = val }
          | WHITELINE { result = [RDoc::Markup::BlankLine.new] }
          | SUBTREE   { result = val[0].parts }
          ;

    headline : HEADLINE {
      # val[0] is like [level, title]
      title = @inline_parser.parse(val[0][1])
      result = RDoc::Markup::Heading.new(val[0][0], title)
    }
    ;

    include : INCLUDE {
      result = RDoc::Markup::Include.new val[0], @include_path
    }
    ;

    textblock : textblockcontent = DUMMY {
      # val[0] is Array of String
      result = paragraph val[0]
    }
    ;

    textblockcontent : textblockcontent STRINGLINE { result << val[1].rstrip }
                     | STRINGLINE { result = [val[0].rstrip] }
                     ;

    verbatim : INDENT verbatimcontent DEDENT {
      # val[1] is Array of String
      content = cut_off val[1]
      result = RDoc::Markup::Verbatim.new(*content)

      # imform to lexer.
      @in_verbatim = false
    }
    ;

    verbatim_after_lists : verbatimcontent {
      # val[0] is Array of String
      content = cut_off val[0]
      result = RDoc::Markup::Verbatim.new(*content)

      # imform to lexer.
      @in_verbatim = false
    }
    ;

    verbatimcontent : verbatimcontent STRINGLINE {
      result << val[1]
    } | verbatimcontent INDENT verbatimcontent DEDENT {
      result.concat val[2]
    } | verbatimcontent WHITELINE {
      result << "\n"
    } | STRINGLINE {
      result = val
      # inform to lexer.
      @in_verbatim = true
    }
    ;

    list : itemlist
         | enumlist
         | desclist
         | methodlist
         ;

    lists : lists2 = DUMMY {
      result = val[0]
    } | INDENT lists2 DEDENT {
      result = val[1]
    } | INDENT lists2 verbatim_after_lists DEDENT {
      result = val[1].push(val[2])
    }
    ;

    lists2 : lists2 list { result = val[0] << val[1] }
           | list { result = [val[0]] }
           ;

    itemlist : itemlistitems  = DUMMY {
      result = RDoc::Markup::List.new :BULLET, *val[0]
    }
    ;

    itemlistitems : itemlistitems itemlistitem { result.push(val[1]) }
                  | itemlistitem { result = val }
                  ;

    itemlistitem : first_textblock_in_itemlist other_blocks_in_list DEDENT {
      result = RDoc::Markup::ListItem.new nil, val[0], *val[1]
    }
    ;

    enumlist :  enumlistitems  = DUMMY {
      result = RDoc::Markup::List.new :NUMBER, *val[0]
    }
    ;

    enumlistitems : enumlistitems enumlistitem { result.push(val[1]) }
                  | enumlistitem { result = val }
                  ;

    enumlistitem : first_textblock_in_enumlist other_blocks_in_list DEDENT {
      result = RDoc::Markup::ListItem.new nil, val[0], *val[1]
    }
    ;

    desclist : desclistitems  = DUMMY {
      result = RDoc::Markup::List.new :NOTE, *val[0]
    }
    ;

    desclistitems : desclistitems desclistitem { result.push(val[1]) }
                  | desclistitem { result = val }
                  ;

    desclistitem : DESCLISTLINE description_part DEDENT {
      term = @inline_parser.parse val[0].strip

      result = RDoc::Markup::ListItem.new term, *val[1]
    }
    ;

    methodlist : methodlistitems  = DUMMY {
      result = RDoc::Markup::List.new :LABEL, *val[0]
    }
    ;

    methodlistitems : methodlistitems methodlistitem { result.push(val[1]) }
                    | methodlistitem { result = val }
                    ;

    methodlistitem : METHODLISTLINE description_part DEDENT {
      result = RDoc::Markup::ListItem.new "<tt>#{val[0].strip}</tt>", *val[1]
    }
    ;

    description_part : whitelines textblock blocks_in_list {
      result = [val[1]].concat(val[2])
    } | whitelines textblock {
      result = [val[1]]
    } | whitelines INDENT blocks_in_list DEDENT {
      result = val[2]
    } | whitelines {
      result = []
    }
    ;

    blocks_in_list : blocks_in_list block_in_list { result.concat val[1] }
                   | block_in_list
                   ;

    block_in_list : textblock { result = val }
                  | verbatim  { result = val }
                  | lists
                  | WHITELINE { result = [] }
                  ;

    whitelines  : whitelines2
                |
                ;

    whitelines2 : WHITELINE whitelines2
                | WHITELINE
                ;

    first_textblock_in_itemlist : ITEMLISTLINE textblockcontent {
      result = paragraph [val[0]].concat(val[1])
    } | ITEMLISTLINE {
      result = paragraph [val[0]]
    }
    ;

    first_textblock_in_enumlist : ENUMLISTLINE textblockcontent {
      result = paragraph [val[0]].concat(val[1])
    } | ENUMLISTLINE {
      result = paragraph [val[0]]
    }
    ;

    other_blocks_in_list : verbatim blocks_in_list {
      result = [val[0]].concat(val[1])
    } | lists blocks_in_list     { result.concat val[1] }
      | WHITELINE blocks_in_list { result = val[1] }
      | verbatim                 { result = val }
      | lists
      | WHITELINE                { result = [] }
      |                          { result = [] }
      ;
end

---- inner

# :stopdoc:

TMPFILE = ["rdtmp", $$, 0]

MARK_TO_LEVEL = {
  '='    => 1,
  '=='   => 2,
  '==='  => 3,
  '====' => 4,
  '+'    => 5,
  '++'   => 6,
}

# :startdoc:

##
# Footnotes for this document

attr_reader :footnotes

##
# Labels for items in this document

attr_reader :labels

##
# Path to find included files in

attr_accessor :include_path

##
# Creates a new RDoc::RD::BlockParser.  Use #parse to parse an rd-format
# document.

def initialize
  @inline_parser = RDoc::RD::InlineParser.new self
  @include_path = []

  # for testing
  @footnotes = []
  @labels    = {}
end

##
# Parses +src+ and returns an RDoc::Markup::Document.

def parse src
  @src = src
  @src.push false

  @footnotes = []
  @labels    = {}

  # @i: index(line no.) of src
  @i = 0

  # stack for current indentation
  @indent_stack = []

  # how indented.
  @current_indent = @indent_stack.join("")

  # RDoc::RD::BlockParser for tmp src
  @subparser = nil

  # which part is in now
  @in_part = nil
  @part_content = []

  @in_verbatim = false

  @yydebug = true

  document = do_parse

  unless @footnotes.empty? then
    blankline = document.parts.pop

    document.parts << RDoc::Markup::Rule.new(1)
    document.parts.concat @footnotes

    document.parts.push blankline
  end

  document
end

##
# Returns the next token from the document

def next_token # :nodoc:
  # preprocessing
  # if it is not in RD part
  # => method
  while @in_part != "rd"
    line = @src[@i]
    @i += 1 # next line

    case line
    # src end
    when false
      return [false, false]
    # RD part begin
    when /^=begin\s*(?:\bRD\b.*)?\s*$/
      if @in_part # if in non-RD part
        @part_content.push(line)
      else
        @in_part = "rd"
        return [:WHITELINE, "=begin\n"] # <= for textblockand
      end
    # non-RD part begin
    when /^=begin\s+(\w+)/
      part = $1
      if @in_part # if in non-RD part
        @part_content.push(line)
      else
        @in_part = part if @tree.filter[part] # if filter exists
#  p "BEGIN_PART: #{@in_part}" # DEBUG
      end
    # non-RD part end
    when /^=end/
      if @in_part # if in non-RD part
#  p "END_PART: #{@in_part}" # DEBUG
        # make Part-in object
        part = RDoc::RD::Part.new(@part_content.join(""), @tree, "r")
        @part_content.clear
        # call filter, part_out is output(Part object)
        part_out = @tree.filter[@in_part].call(part)

        if @tree.filter[@in_part].mode == :rd # if output is RD formatted
          subtree = parse_subtree(part_out.to_a)
        else # if output is target formatted
          basename = TMPFILE.join('.')
          TMPFILE[-1] += 1
          tmpfile = open(@tree.tmp_dir + "/" + basename + ".#{@in_part}", "w")
          tmpfile.print(part_out)
          tmpfile.close
          subtree = parse_subtree(["=begin\n", "<<< #{basename}\n", "=end\n"])
        end
        @in_part = nil
        return [:SUBTREE, subtree]
      end
    else
      if @in_part # if in non-RD part
        @part_content.push(line)
      end
    end
  end

  @current_indent = @indent_stack.join("")
  line = @src[@i]
  case line
  when false
    if_current_indent_equal("") do
      [false, false]
    end
  when /^=end/
    if_current_indent_equal("") do
      @in_part = nil
      [:WHITELINE, "=end"] # MUST CHANGE??
    end
  when /^\s*$/
    @i += 1 # next line
    return [:WHITELINE, ':WHITELINE']
  when /^\#/  # comment line
    @i += 1 # next line
    self.next_token()
  when /^(={1,4})(?!=)\s*(?=\S)/, /^(\+{1,2})(?!\+)\s*(?=\S)/
    rest = $'                    # '
    rest.strip!
    mark = $1
    if_current_indent_equal("") do
      return [:HEADLINE, [MARK_TO_LEVEL[mark], rest]]
    end
  when /^<<<\s*(\S+)/
    file = $1
    if_current_indent_equal("") do
      suffix = file[-3 .. -1]
      if suffix == ".rd" or suffix == ".rb"
        subtree = parse_subtree(get_included(file))
        [:SUBTREE, subtree]
      else
        [:INCLUDE, file]
      end
    end
  when /^(\s*)\*(\s*)/
    rest = $'                   # '
    newIndent = $2
    if_current_indent_equal($1) do
      if @in_verbatim
        [:STRINGLINE, line]
      else
        @indent_stack.push("\s" << newIndent)
        [:ITEMLISTLINE, rest]
      end
    end
  when /^(\s*)(\(\d+\))(\s*)/
    rest = $'                     # '
    mark = $2
    newIndent = $3
    if_current_indent_equal($1) do
      if @in_verbatim
        [:STRINGLINE, line]
      else
        @indent_stack.push("\s" * mark.size << newIndent)
        [:ENUMLISTLINE, rest]
      end
    end
  when /^(\s*):(\s*)/
    rest = $'                    # '
    newIndent = $2
    if_current_indent_equal($1) do
      if @in_verbatim
        [:STRINGLINE, line]
      else
        @indent_stack.push("\s#{$2}")
        [:DESCLISTLINE, rest]
      end
    end
  when /^(\s*)---(?!-|\s*$)/
    indent = $1
    rest = $'
    /\s*/ === rest
    term = $'
    new_indent = $&
    if_current_indent_equal(indent) do
      if @in_verbatim
        [:STRINGLINE, line]
      else
        @indent_stack.push("\s\s\s" + new_indent)
        [:METHODLISTLINE, term]
      end
    end
  when /^(\s*)/
    if_current_indent_equal($1) do
      [:STRINGLINE, line]
    end
  else
    raise "[BUG] parsing error may occured."
  end
end

##
# Yields to the given block if +indent+ matches the current indent, otherwise
# an indentation token is processed.

def if_current_indent_equal(indent)
  indent = indent.sub(/\t/, "\s" * 8)
  if @current_indent == indent
    @i += 1 # next line
    yield
  elsif indent.index(@current_indent) == 0
    @indent_stack.push(indent[@current_indent.size .. -1])
    [:INDENT, ":INDENT"]
  else
    @indent_stack.pop
    [:DEDENT, ":DEDENT"]
  end
end
private :if_current_indent_equal

##
# Cuts off excess whitespace in +src+

def cut_off(src)
  ret = []
  whiteline_buf = []

  line = src.shift
  /^\s*/ =~ line

  indent = Regexp.quote($&)
  ret.push($')

  while line = src.shift
    if /^(\s*)$/ =~ line
      whiteline_buf.push(line)
    elsif /^#{indent}/ =~ line
      unless whiteline_buf.empty?
        ret.concat(whiteline_buf)
        whiteline_buf.clear
      end
      ret.push($')
    else
      raise "[BUG]: probably Parser Error while cutting off.\n"
    end
  end
  ret
end
private :cut_off

def set_term_to_element(parent, term)
#  parent.set_term_under_document_struct(term, @tree.document_struct)
  parent.set_term_without_document_struct(term)
end
private :set_term_to_element

##
# Raises a ParseError when invalid formatting is found

def on_error(et, ev, _values)
  prv, cur, nxt = format_line_num(@i, @i+1, @i+2)

  raise ParseError, <<Msg

RD syntax error: line #{@i+1}:
  #{prv}  |#{@src[@i-1].chomp}
  #{cur}=>|#{@src[@i].chomp}
  #{nxt}  |#{@src[@i+1].chomp}

Msg
end

##
# Current line number

def line_index
  @i
end

##
# Parses subtree +src+

def parse_subtree src
  @subparser ||= RDoc::RD::BlockParser.new

  @subparser.parse src
end
private :parse_subtree

##
# Retrieves the content for +file+ from the include_path

def get_included(file)
  included = []

  @include_path.each do |dir|
    file_name = File.join dir, file

    if File.exist? file_name then
      included = IO.readlines file_name
      break
    end
  end

  included
end
private :get_included

##
# Formats line numbers +line_numbers+ prettily

def format_line_num(*line_numbers)
  width = line_numbers.collect{|i| i.to_s.length }.max
  line_numbers.collect{|i| sprintf("%#{width}d", i) }
end
private :format_line_num

##
# Retrieves the content of +values+ as a single String

def content values
 values.map { |value| value.content }.join
end

##
# Creates a paragraph for +value+

def paragraph value
  content = cut_off(value).join(' ').rstrip
  contents = @inline_parser.parse content

  RDoc::Markup::Paragraph.new(*contents)
end

##
# Adds footnote +content+ to the document

def add_footnote content
  index = @footnotes.length / 2 + 1

  footmark_link = "{^#{index}}[rdoc-label:footmark-#{index}:foottext-#{index}]"

  @footnotes << RDoc::Markup::Paragraph.new(footmark_link, ' ', *content)
  @footnotes << RDoc::Markup::BlankLine.new

  index
end

##
# Adds label +label+ to the document

def add_label label
  @labels[label] = true

  label
end

# :stopdoc:

---- header
class RDoc::RD

##
# RD format parser for headings, paragraphs, lists, verbatim sections that
# exist as blocks.

---- footer
end