Import RDoc 2.5

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27147 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 528 insertions, 0 deletions

diff --git a/lib/rdoc/markup/parser.rb b/lib/rdoc/markup/parser.rb
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+require 'strscan'
+require 'rdoc/text'
+
+##
+# A recursive-descent parser for RDoc markup.
+#
+# The parser tokenizes an input string then parses the tokens into a Document.
+# Documents can be converted into output formats by writing a visitor like
+# RDoc::Markup::ToHTML.
+#
+# The parser only handles the block-level constructs Paragraph, List,
+# ListItem, Heading, Verbatim, BlankLine and Rule.  Inline markup such as
+# <tt>\+blah\+</tt> is handled separately by RDoc::Markup::AttributeManager.
+#
+# To see what markup the Parser implements read RDoc.  To see how to use
+# RDoc markup to format text in your program read RDoc::Markup.
+
+class RDoc::Markup::Parser
+
+  include RDoc::Text
+
+  ##
+  # List token types
+
+  LIST_TOKENS = [
+    :BULLET,
+    :LABEL,
+    :LALPHA,
+    :NOTE,
+    :NUMBER,
+    :UALPHA,
+  ]
+
+  ##
+  # Parser error subclass
+
+  class Error < RuntimeError; end
+
+  ##
+  # Raised when the parser is unable to handle the given markup
+
+  class ParseError < Error; end
+
+  ##
+  # Enables display of debugging information
+
+  attr_accessor :debug
+
+  ##
+  # Token accessor
+
+  attr_reader :tokens
+
+  ##
+  # Parsers +str+ into a Document
+
+  def self.parse str
+    parser = new
+    #parser.debug = true
+    parser.tokenize str
+    RDoc::Markup::Document.new(*parser.parse)
+  end
+
+  ##
+  # Returns a token stream for +str+, for testing
+
+  def self.tokenize str
+    parser = new
+    parser.tokenize str
+    parser.tokens
+  end
+
+  ##
+  # Creates a new Parser.  See also ::parse
+
+  def initialize
+    @tokens = []
+    @current_token = nil
+    @debug = false
+
+    @line = 0
+    @line_pos = 0
+  end
+
+  ##
+  # Builds a Heading of +level+
+
+  def build_heading level
+    heading = RDoc::Markup::Heading.new level, text
+    skip :NEWLINE
+
+    heading
+  end
+
+  ##
+  # Builds a List flush to +margin+
+
+  def build_list margin
+    p :list_start => margin if @debug
+
+    list = RDoc::Markup::List.new
+
+    until @tokens.empty? do
+      type, data, column, = get
+
+      case type
+      when :BULLET, :LABEL, :LALPHA, :NOTE, :NUMBER, :UALPHA then
+        list_type = type
+
+        if column < margin then
+          unget
+          break
+        end
+
+        if list.type and list.type != list_type then
+          unget
+          break
+        end
+
+        list.type = list_type
+
+        case type
+        when :NOTE, :LABEL then
+          _, indent, = get # SPACE
+          if :NEWLINE == peek_token.first then
+            get
+            peek_type, new_indent, peek_column, = peek_token
+            indent = new_indent if
+              peek_type == :INDENT and peek_column >= column
+            unget
+          end
+        else
+          data = nil
+          _, indent, = get
+        end
+
+        list_item = build_list_item(margin + indent, data)
+
+        list << list_item if list_item
+      else
+        unget
+        break
+      end
+    end
+
+    p :list_end => margin if @debug
+
+    return nil if list.empty?
+
+    list
+  end
+
+  ##
+  # Builds a ListItem that is flush to +indent+ with type +item_type+
+
+  def build_list_item indent, item_type = nil
+    p :list_item_start => [indent, item_type] if @debug
+
+    list_item = RDoc::Markup::ListItem.new item_type
+
+    until @tokens.empty? do
+      type, data, column = get
+
+      if column < indent and
+         not type == :NEWLINE and
+         (type != :INDENT or data < indent) then
+        unget
+        break
+      end
+
+      case type
+      when :INDENT then
+        unget
+        list_item.push(*parse(indent))
+      when :TEXT then
+        unget
+        list_item << build_paragraph(indent)
+      when :HEADER then
+        list_item << build_heading(data)
+      when :NEWLINE then
+        list_item << RDoc::Markup::BlankLine.new
+      when *LIST_TOKENS then
+        unget
+        list_item << build_list(column)
+      else
+        raise ParseError, "Unhandled token #{@current_token.inspect}"
+      end
+    end
+
+    p :list_item_end => [indent, item_type] if @debug
+
+    return nil if list_item.empty?
+
+    list_item.parts.shift if
+      RDoc::Markup::BlankLine === list_item.parts.first and
+      list_item.length > 1
+
+    list_item
+  end
+
+  ##
+  # Builds a Paragraph that is flush to +margin+
+
+  def build_paragraph margin
+    p :paragraph_start => margin if @debug
+
+    paragraph = RDoc::Markup::Paragraph.new
+
+    until @tokens.empty? do
+      type, data, column, = get
+
+      case type
+      when :INDENT then
+        next if data == margin and peek_token[0] == :TEXT
+
+        unget
+        break
+      when :TEXT then
+        if column != margin then
+          unget
+          break
+        end
+
+        paragraph << data
+        skip :NEWLINE
+      else
+        unget
+        break
+      end
+    end
+
+    p :paragraph_end => margin if @debug
+
+    paragraph
+  end
+
+  ##
+  # Builds a Verbatim that is flush to +margin+
+
+  def build_verbatim margin
+    p :verbatim_begin => margin if @debug
+    verbatim = RDoc::Markup::Verbatim.new
+
+    until @tokens.empty? do
+      type, data, column, = get
+
+      case type
+      when :INDENT then
+        if margin >= data then
+          unget
+          break
+        end
+
+        indent = data - margin
+
+        verbatim << ' ' * indent
+      when :HEADER then
+        verbatim << '=' * data
+
+        _, _, peek_column, = peek_token
+        peek_column ||= column + data
+        verbatim << ' ' * (peek_column - column - data)
+      when :RULE then
+        width = 2 + data
+        verbatim << '-' * width
+
+        _, _, peek_column, = peek_token
+        peek_column ||= column + data + 2
+        verbatim << ' ' * (peek_column - column - width)
+      when :TEXT then
+        verbatim << data
+      when *LIST_TOKENS then
+        if column <= margin then
+          unget
+          break
+        end
+
+        list_marker = case type
+                      when :BULLET                   then '*'
+                      when :LABEL                    then "[#{data}]"
+                      when :LALPHA, :NUMBER, :UALPHA then "#{data}."
+                      when :NOTE                     then "#{data}::"
+                      end
+
+        verbatim << list_marker
+
+        _, data, = get
+
+        verbatim << ' ' * (data - list_marker.length)
+      when :NEWLINE then
+        verbatim << data
+        break unless [:INDENT, :NEWLINE].include? peek_token[0]
+      else
+        unget
+        break
+      end
+    end
+
+    verbatim.normalize
+
+    p :verbatim_end => margin if @debug
+
+    verbatim
+  end
+
+  ##
+  # Pulls the next token from the stream.
+
+  def get
+    @current_token = @tokens.shift
+    p :get => @current_token if @debug
+    @current_token
+  end
+
+  ##
+  # Parses the tokens into a Document
+
+  def parse indent = 0
+    p :parse_start => indent if @debug
+
+    document = []
+
+    until @tokens.empty? do
+      type, data, column, = get
+
+      if type != :INDENT and column < indent then
+        unget
+        break
+      end
+
+      case type
+      when :HEADER then
+        document << build_heading(data)
+      when :INDENT then
+        if indent > data then
+          unget
+          break
+        elsif indent == data then
+          next
+        end
+
+        unget
+        document << build_verbatim(indent)
+      when :NEWLINE then
+        document << RDoc::Markup::BlankLine.new
+        skip :NEWLINE, false
+      when :RULE then
+        document << RDoc::Markup::Rule.new(data)
+        skip :NEWLINE
+      when :TEXT then
+        unget
+        document << build_paragraph(indent)
+
+        # we're done with this paragraph (indent mismatch)
+        break if peek_token[0] == :TEXT
+      when *LIST_TOKENS then
+        unget
+
+        list = build_list(indent)
+
+        document << list if list
+
+        # we're done with this list (indent mismatch)
+        break if LIST_TOKENS.include? peek_token.first and indent > 0
+      else
+        type, data, column, line = @current_token
+        raise ParseError,
+              "Unhandled token #{type} (#{data.inspect}) at #{line}:#{column}"
+      end
+    end
+
+    p :parse_end => indent if @debug
+
+    document
+  end
+
+  ##
+  # Returns the next token on the stream without modifying the stream
+
+  def peek_token
+    token = @tokens.first || []
+    p :peek => token if @debug
+    token
+  end
+
+  ##
+  # Skips a token of +token_type+, optionally raising an error.
+
+  def skip token_type, error = true
+    type, data, = get
+
+    return unless type # end of stream
+
+    return @current_token if token_type == type
+
+    unget
+
+    raise ParseError, "expected #{token_type} got #{@current_token.inspect}" if
+      error
+  end
+
+  ##
+  # Consumes tokens until NEWLINE and turns them back into text
+
+  def text
+    text = ''
+
+    loop do
+      type, data, = get
+
+      text << case type
+              when :BULLET then
+                _, space, = get # SPACE
+                "*#{' ' * (space - 1)}"
+              when :LABEL then
+                _, space, = get # SPACE
+                "[#{data}]#{' ' * (space - data.length - 2)}"
+              when :LALPHA, :NUMBER, :UALPHA then
+                _, space, = get # SPACE
+                "#{data}.#{' ' * (space - 2)}"
+              when :NOTE then
+                _, space = get # SPACE
+                "#{data}::#{' ' * (space - data.length - 2)}"
+              when :TEXT then
+                data
+              when :NEWLINE then
+                unget
+                break
+              when nil then
+                break
+              else
+                raise ParseError, "unhandled token #{@current_token.inspect}"
+              end
+    end
+
+    text
+  end
+
+  ##
+  # Calculates the column and line of the current token based on +offset+.
+
+  def token_pos offset
+    [offset - @line_pos, @line]
+  end
+
+  ##
+  # Turns text +input+ into a stream of tokens
+
+  def tokenize input
+    s = StringScanner.new input
+
+    @line = 0
+    @line_pos = 0
+
+    until s.eos? do
+      pos = s.pos
+
+      @tokens << case
+                 when s.scan(/\r?\n/) then
+                   token = [:NEWLINE, s.matched, *token_pos(pos)]
+                   @line_pos = s.pos
+                   @line += 1
+                   token
+                 when s.scan(/ +/) then
+                   [:INDENT, s.matched_size, *token_pos(pos)]
+                 when s.scan(/(=+)\s+/) then
+                   level = s[1].length
+                   level = 6 if level > 6
+                   @tokens << [:HEADER, level, *token_pos(pos)]
+
+                   pos = s.pos
+                   s.scan(/.*/)
+                   [:TEXT, s.matched, *token_pos(pos)]
+                 when s.scan(/^(-{3,}) *$/) then
+                   [:RULE, s[1].length - 2, *token_pos(pos)]
+                 when s.scan(/([*-])\s+/) then
+                   @tokens << [:BULLET, :BULLET, *token_pos(pos)]
+                   [:SPACE, s.matched_size, *token_pos(pos)]
+                 when s.scan(/([a-z]|\d+)\.[ \t]+\S/i) then
+                   list_label = s[1]
+                   width      = s.matched_size - 1
+
+                   s.pos -= 1 # unget \S
+
+                   list_type = case list_label
+                               when /[a-z]/ then :LALPHA
+                               when /[A-Z]/ then :UALPHA
+                               when /\d/    then :NUMBER
+                               else
+                                 raise ParseError, "BUG token #{list_label}"
+                               end
+
+                   @tokens << [list_type, list_label, *token_pos(pos)]
+                   [:SPACE, width, *token_pos(pos)]
+                 when s.scan(/\[(.*?)\]( +|$)/) then
+                   @tokens << [:LABEL, s[1], *token_pos(pos)]
+                   [:SPACE, s.matched_size, *token_pos(pos)]
+                 when s.scan(/(.*?)::( +|$)/) then
+                   @tokens << [:NOTE, s[1], *token_pos(pos)]
+                   [:SPACE, s.matched_size, *token_pos(pos)]
+                 else s.scan(/.*/)
+                   [:TEXT, s.matched, *token_pos(pos)]
+                 end
+    end
+
+    self
+  end
+
+  ##
+  # Returns the current token or +token+ to the token stream
+
+  def unget token = @current_token
+    p :unget => token if @debug
+    raise Error, 'too many #ungets' if token == @tokens.first
+    @tokens.unshift token if token
+  end
+
+end
+
+require 'rdoc/markup/blank_line'
+require 'rdoc/markup/document'
+require 'rdoc/markup/heading'
+require 'rdoc/markup/list'
+require 'rdoc/markup/list_item'
+require 'rdoc/markup/paragraph'
+require 'rdoc/markup/rule'
+require 'rdoc/markup/verbatim'
+