Redmine

#                                vim:ts=4:sw=4:

# = RedCloth - Textile and Markdown Hybrid for Ruby

#

# Homepage::  http://whytheluckystiff.net/ruby/redcloth/

# Author::    why the lucky stiff (http://whytheluckystiff.net/)

# Copyright:: (cc) 2004 why the lucky stiff (and his puppet organizations.)

# License::   BSD

#

# (see http://hobix.com/textile/ for a Textile Reference.)

#

# Based on (and also inspired by) both:

#

# PyTextile: http://diveintomark.org/projects/textile/textile.py.txt

# Textism for PHP: http://www.textism.com/tools/textile/

#

#

# = RedCloth

#

# RedCloth is a Ruby library for converting Textile and/or Markdown

# into HTML.  You can use either format, intermingled or separately.

# You can also extend RedCloth to honor your own custom text stylings.

#

# RedCloth users are encouraged to use Textile if they are generating

# HTML and to use Markdown if others will be viewing the plain text.

#

# == What is Textile?

#

# Textile is a simple formatting style for text

# documents, loosely based on some HTML conventions.

#

# == Sample Textile Text

#

#  h2. This is a title

#

#  h3. This is a subhead

#

#  This is a bit of paragraph.

#

#  bq. This is a blockquote.

#

# = Writing Textile

#

# A Textile document consists of paragraphs.  Paragraphs

# can be specially formatted by adding a small instruction

# to the beginning of the paragraph.

#

#  h[n].   Header of size [n].

#  bq.     Blockquote.

#  #       Numeric list.

#  *       Bulleted list.

#

# == Quick Phrase Modifiers

#

# Quick phrase modifiers are also included, to allow formatting

# of small portions of text within a paragraph.

#

#  \_emphasis\_

#  \_\_italicized\_\_

#  \*strong\*

#  \*\*bold\*\*

#  ??citation??

#  -deleted text-

#  +inserted text+

#  ^superscript^

#  ~subscript~

#  @code@

#  %(classname)span%

#

#  ==notextile== (leave text alone)

#

# == Links

#

# To make a hypertext link, put the link text in "quotation 

# marks" followed immediately by a colon and the URL of the link.

# 

# Optional: text in (parentheses) following the link text, 

# but before the closing quotation mark, will become a Title 

# attribute for the link, visible as a tool tip when a cursor is above it.

# 

# Example:

#

#  "This is a link (This is a title) ":http://www.textism.com

# 

# Will become:

# 

#  <a href="http://www.textism.com" title="This is a title">This is a link</a>

#

# == Images

#

# To insert an image, put the URL for the image inside exclamation marks.

#

# Optional: text that immediately follows the URL in (parentheses) will 

# be used as the Alt text for the image. Images on the web should always 

# have descriptive Alt text for the benefit of readers using non-graphical 

# browsers.

#

# Optional: place a colon followed by a URL immediately after the 

# closing ! to make the image into a link.

# 

# Example:

#

#  !http://www.textism.com/common/textist.gif(Textist)!

#

# Will become:

#

#  <img src="http://www.textism.com/common/textist.gif" alt="Textist" />

#

# With a link:

#

#  !/common/textist.gif(Textist)!:http://textism.com

#

# Will become:

#

#  <a href="http://textism.com"><img src="/https/www.redmine.org/common/textist.gif" alt="Textist" /></a>

#

# == Defining Acronyms

#

# HTML allows authors to define acronyms via the tag. The definition appears as a 

# tool tip when a cursor hovers over the acronym. A crucial aid to clear writing, 

# this should be used at least once for each acronym in documents where they appear.

#

# To quickly define an acronym in Textile, place the full text in (parentheses) 

# immediately following the acronym.

# 

# Example:

#

#  ACLU(American Civil Liberties Union)

#

# Will become:

#

#  <acronym title="American Civil Liberties Union">ACLU</acronym>

#

# == Adding Tables

#

# In Textile, simple tables can be added by seperating each column by

# a pipe.

#

#     |a|simple|table|row|

#     |And|Another|table|row|

#

# Attributes are defined by style definitions in parentheses.

#

#     table(border:1px solid black).

#     (background:#ddd;color:red). |{}| | | |

#

# == Using RedCloth

# 

# RedCloth is simply an extension of the String class, which can handle

# Textile formatting.  Use it like a String and output HTML with its

# RedCloth#to_html method.

#

#  doc = RedCloth.new "

#

#  h2. Test document

#

#  Just a simple test."

#

#  puts doc.to_html

#

# By default, RedCloth uses both Textile and Markdown formatting, with

# Textile formatting taking precedence.  If you want to turn off Markdown

# formatting, to boost speed and limit the processor:

#

#  class RedCloth::Textile.new( str )

class RedCloth < String

    VERSION = '3.0.4'

    DEFAULT_RULES = [:textile, :markdown]

    #

    # Two accessor for setting security restrictions.

    #

    # This is a nice thing if you're using RedCloth for

    # formatting in public places (e.g. Wikis) where you

    # don't want users to abuse HTML for bad things.

    #

    # If +:filter_html+ is set, HTML which wasn't

    # created by the Textile processor will be escaped.

    #

    # If +:filter_styles+ is set, it will also disable

    # the style markup specifier. ('{color: red}')

    #

    attr_accessor :filter_html, :filter_styles

    #

    # Accessor for toggling hard breaks.

    #

    # If +:hard_breaks+ is set, single newlines will

    # be converted to HTML break tags.  This is the

    # default behavior for traditional RedCloth.

    #

    attr_accessor :hard_breaks

    # Accessor for toggling lite mode.

    #

    # In lite mode, block-level rules are ignored.  This means

    # that tables, paragraphs, lists, and such aren't available.

    # Only the inline markup for bold, italics, entities and so on.

    #

    #   r = RedCloth.new( "And then? She *fell*!", [:lite_mode] )

    #   r.to_html

    #   #=> "And then? She <strong>fell</strong>!"

    #

    attr_accessor :lite_mode

    #

    # Accessor for toggling span caps.

    #

    # Textile places `span' tags around capitalized

    # words by default, but this wreaks havoc on Wikis.

    # If +:no_span_caps+ is set, this will be

    # suppressed.

    #

    attr_accessor :no_span_caps

    #

    # Establishes the markup predence.  Available rules include:

    #

    # == Textile Rules

    #

    # The following textile rules can be set individually.  Or add the complete

    # set of rules with the single :textile rule, which supplies the rule set in

    # the following precedence:

    #

    # refs_textile::          Textile references (i.e. [hobix]http://hobix.com/)

    # block_textile_table::   Textile table block structures

    # block_textile_lists::   Textile list structures

    # block_textile_prefix::  Textile blocks with prefixes (i.e. bq., h2., etc.)

    # inline_textile_image::  Textile inline images

    # inline_textile_link::   Textile inline links

    # inline_textile_span::   Textile inline spans

    # glyphs_textile:: Textile entities (such as em-dashes and smart quotes)

    #

    # == Markdown

    #

    # refs_markdown::         Markdown references (for example: [hobix]: http://hobix.com/)

    # block_markdown_setext:: Markdown setext headers

    # block_markdown_atx::    Markdown atx headers

    # block_markdown_rule::   Markdown horizontal rules

    # block_markdown_bq::     Markdown blockquotes

    # block_markdown_lists::  Markdown lists

    # inline_markdown_link::  Markdown links

    attr_accessor :rules

    # Returns a new RedCloth object, based on _string_ and

    # enforcing all the included _restrictions_.

    #

    #   r = RedCloth.new( "h1. A <b>bold</b> man", [:filter_html] )

    #   r.to_html

    #     #=>"<h1>A &lt;b&gt;bold&lt;/b&gt; man</h1>"

    #

    def initialize( string, restrictions = [] )

        restrictions.each { |r| method( "#{ r }=" ).call( true ) }

        super( string )

    end

    #

    # Generates HTML from the Textile contents.

    #

    #   r = RedCloth.new( "And then? She *fell*!" )

    #   r.to_html( true )

    #     #=>"And then? She <strong>fell</strong>!"

    #

    def to_html( *rules )

        rules = DEFAULT_RULES if rules.empty?

        # make our working copy

        text = self.dup

        @urlrefs = {}

        @shelf = []

        textile_rules = [:refs_textile, :block_textile_table, :block_textile_lists,

                         :block_textile_prefix, :inline_textile_image, :inline_textile_link,

                         :inline_textile_code, :inline_textile_span]

        markdown_rules = [:refs_markdown, :block_markdown_setext, :block_markdown_atx, :block_markdown_rule,

                          :block_markdown_bq, :block_markdown_lists, 

                          :inline_markdown_reflink, :inline_markdown_link]

        @rules = rules.collect do |rule|

            case rule

            when :markdown

                markdown_rules

            when :textile

                textile_rules

            else

                rule

            end

        end.flatten

        # standard clean up

        incoming_entities text 

        clean_white_space text 

        # start processor

        @pre_list = []

        rip_offtags text

        no_textile text

        escape_html_tags text

        hard_break text 

        unless @lite_mode

            refs text

            blocks text

        end

        inline text

        smooth_offtags text

        retrieve text

        text.gsub!( /<\/?notextile>/, '' )

        text.gsub!( /x%x%/, '&' )

        clean_html text if filter_html

        text.strip!

        text

    end

    #######

    private

    #######

    #

    # Mapping of 8-bit ASCII codes to HTML numerical entity equivalents.

    # (from PyTextile)

    #

    TEXTILE_TAGS =

        [[128, 8364], [129, 0], [130, 8218], [131, 402], [132, 8222], [133, 8230], 

         [134, 8224], [135, 8225], [136, 710], [137, 8240], [138, 352], [139, 8249], 

         [140, 338], [141, 0], [142, 0], [143, 0], [144, 0], [145, 8216], [146, 8217], 

         [147, 8220], [148, 8221], [149, 8226], [150, 8211], [151, 8212], [152, 732], 

         [153, 8482], [154, 353], [155, 8250], [156, 339], [157, 0], [158, 0], [159, 376]].

        collect! do |a, b|

            [a.chr, ( b.zero? and "" or "&#{ b };" )]

        end

    #

    # Regular expressions to convert to HTML.

    #

    A_HLGN = /(?:(?:<>|<|>|\=|[()]+)+)/

    A_VLGN = /[\-^~]/

    C_CLAS = '(?:\([^)]+\))'

    C_LNGE = '(?:\[[^\]]+\])'

    C_STYL = '(?:\{[^}]+\})'

    S_CSPN = '(?:\\\\\d+)'

    S_RSPN = '(?:/\d+)'

    A = "(?:#{A_HLGN}?#{A_VLGN}?|#{A_VLGN}?#{A_HLGN}?)"

    S = "(?:#{S_CSPN}?#{S_RSPN}|#{S_RSPN}?#{S_CSPN}?)"

    C = "(?:#{C_CLAS}?#{C_STYL}?#{C_LNGE}?|#{C_STYL}?#{C_LNGE}?#{C_CLAS}?|#{C_LNGE}?#{C_STYL}?#{C_CLAS}?)"

    # PUNCT = Regexp::quote( '!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~' )

    PUNCT = Regexp::quote( '!"#$%&\'*+,-./:;=?@\\^_`|~' )

    PUNCT_NOQ = Regexp::quote( '!"#$&\',./:;=?@\\`|' )

    PUNCT_Q = Regexp::quote( '*-_+^~%' )

    HYPERLINK = '(\S+?)([^\w\s/;=\?]*?)(?=\s|<|$)'

    # Text markup tags, don't conflict with block tags

    SIMPLE_HTML_TAGS = [

        'tt', 'b', 'i', 'big', 'small', 'em', 'strong', 'dfn', 'code', 

        'samp', 'kbd', 'var', 'cite', 'abbr', 'acronym', 'a', 'img', 'br',

        'br', 'map', 'q', 'sub', 'sup', 'span', 'bdo'

    ]

    QTAGS = [

        ['**', 'b', :limit],

        ['*', 'strong', :limit],

        ['??', 'cite', :limit],

        ['-', 'del', :limit],

        ['__', 'i', :limit],

        ['_', 'em', :limit],

        ['%', 'span', :limit],

        ['+', 'ins', :limit],

        ['^', 'sup', :limit],

        ['~', 'sub', :limit]

    ] 

    QTAGS.collect! do |rc, ht, rtype|

        rcq = Regexp::quote rc

        re =

            case rtype

            when :limit

                /(^|[>\s])

                (#{rcq})

                (#{C})

                (?::(\S+?))?

                ([^\s\-].*?[^\s\-]|\w)

                #{rcq}

                (?=[[:punct:]]|\s|$)/x

            else

                /(#{rcq})

                (#{C})

                (?::(\S+))?

                ([^\s\-].*?[^\s\-]|\w)

                #{rcq}/xm 

            end

        [rc, ht, re, rtype]

    end

    # Elements to handle

    GLYPHS = [

    #   [ /([^\s\[{(>])?\'([dmst]\b|ll\b|ve\b|\s|:|$)/, '\1’\2' ], # single closing

    #   [ /([^\s\[{(>#{PUNCT_Q}][#{PUNCT_Q}]*)\'/, '\1’' ], # single closing

    #   [ /\'(?=[#{PUNCT_Q}]*(s\b|[\s#{PUNCT_NOQ}]))/, '’' ], # single closing

    #   [ /\'/, '‘' ], # single opening

        [ /</, '&lt;' ], # less-than

        [ />/, '>' ], # greater-than

    #   [ /([^\s\[{(])?"(\s|:|$)/, '\1”\2' ], # double closing

    #   [ /([^\s\[{(>#{PUNCT_Q}][#{PUNCT_Q}]*)"/, '\1”' ], # double closing

    #   [ /"(?=[#{PUNCT_Q}]*[\s#{PUNCT_NOQ}])/, '”' ], # double closing

    #   [ /"/, '“' ], # double opening

        [ /\b( )?\.{3}/, '\1…' ], # ellipsis

        [ /\b([A-Z][A-Z0-9]{2,})\b(?:[(]([^)]*)[)])/, '<acronym title="\2">\1</acronym>' ], # 3+ uppercase acronym

        [ /(^|[^"][>\s])([A-Z][A-Z0-9 ]+[A-Z0-9])([^<A-Za-z0-9]|$)/, '\1<span class="caps">\2</span>\3', :no_span_caps ], # 3+ uppercase caps

        [ /(\.\s)?\s?--\s?/, '\1—' ], # em dash

        [ /\s->\s/, ' → ' ], # right arrow

        [ /\s-\s/, ' – ' ], # en dash

        [ /(\d+) ?x ?(\d+)/, '\1×\2' ], # dimension sign

        [ /\b ?[(\[]TM[\])]/i, '™' ], # trademark

        [ /\b ?[(\[]R[\])]/i, '®' ], # registered

        [ /\b ?[(\[]C[\])]/i, '©' ] # copyright

    ]

    H_ALGN_VALS = {

        '<' => 'left',

        '=' => 'center',

        '>' => 'right',

        '<>' => 'justify'

    }

    V_ALGN_VALS = {

        '^' => 'top',

        '-' => 'middle',

        '~' => 'bottom'

    }

    #

    # Flexible HTML escaping

    #

    def htmlesc( str, mode )

        str.gsub!( '&', '&' )

        str.gsub!( '"', '"' ) if mode != :NoQuotes

        str.gsub!( "'", ''' ) if mode == :Quotes

        str.gsub!( '<', '&lt;')

        str.gsub!( '>', '>')

    end

    # Search and replace for Textile glyphs (quotes, dashes, other symbols)

    def pgl( text )

        GLYPHS.each do |re, resub, tog|

            next if tog and method( tog ).call

            text.gsub! re, resub

        end

    end

    # Parses Textile attribute lists and builds an HTML attribute string

    def pba( text_in, element = "" )

        return '' unless text_in

        style = []

        text = text_in.dup

        if element == 'td'

            colspan = $1 if text =~ /\\(\d+)/

            rowspan = $1 if text =~ /\/(\d+)/

            style << "vertical-align:#{ v_align( $& ) };" if text =~ A_VLGN

        end

        style << "#{ $1 };" if not filter_styles and

            text.sub!( /\{([^}]*)\}/, '' )

        lang = $1 if

            text.sub!( /\[([^)]+?)\]/, '' )

        cls = $1 if

            text.sub!( /\(([^()]+?)\)/, '' )

        style << "padding-left:#{ $1.length }em;" if

            text.sub!( /([(]+)/, '' )

        style << "padding-right:#{ $1.length }em;" if text.sub!( /([)]+)/, '' )

        style << "text-align:#{ h_align( $& ) };" if text =~ A_HLGN

        cls, id = $1, $2 if cls =~ /^(.*?)#(.*)$/

        atts = ''

        atts << " style=\"#{ style.join }\"" unless style.empty?

        atts << " class=\"#{ cls }\"" unless cls.to_s.empty?

        atts << " lang=\"#{ lang }\"" if lang

        atts << " id=\"#{ id }\"" if id

        atts << " colspan=\"#{ colspan }\"" if colspan

        atts << " rowspan=\"#{ rowspan }\"" if rowspan

        atts

    end

    TABLE_RE = /^(?:table(_?#{S}#{A}#{C})\. ?\n)?^(#{A}#{C}\.? ?\|.*?\|)(\n\n|\Z)/m

    # Parses a Textile table block, building HTML from the result.

    def block_textile_table( text ) 

        text.gsub!( TABLE_RE ) do |matches|

            tatts, fullrow = $~[1..2]

            tatts = pba( tatts, 'table' )

            tatts = shelve( tatts ) if tatts

            rows = []

            fullrow.

            split( /\|$/m ).

            delete_if { |x| x.empty? }.

            each do |row|

                ratts, row = pba( $1, 'tr' ), $2 if row =~ /^(#{A}#{C}\. )(.*)/m

                cells = []

                row.split( '|' ).each do |cell|

                    ctyp = 'd'

                    ctyp = 'h' if cell =~ /^_/

                    catts = ''

                    catts, cell = pba( $1, 'td' ), $2 if cell =~ /^(_?#{S}#{A}#{C}\. ?)(.*)/

                    unless cell.strip.empty?

                        catts = shelve( catts ) if catts

                        cells << "\t\t\t<t#{ ctyp }#{ catts }>#{ cell }</t#{ ctyp }>" 

                    end

                end

                ratts = shelve( ratts ) if ratts

                rows << "\t\t<tr#{ ratts }>\n#{ cells.join( "\n" ) }\n\t\t</tr>"

            end

            "\t<table#{ tatts }>\n#{ rows.join( "\n" ) }\n\t</table>\n\n"

        end

    end

    LISTS_RE = /^([#*]+?#{C} .*?)$(?![^#*])/m

    LISTS_CONTENT_RE = /^([#*]+)(#{A}#{C}) (.*)$/m

    # Parses Textile lists and generates HTML

    def block_textile_lists( text ) 

        text.gsub!( LISTS_RE ) do |match|

            lines = match.split( /\n/ )

            last_line = -1

            depth = []

            lines.each_with_index do |line, line_id|

                if line =~ LISTS_CONTENT_RE 

                    tl,atts,content = $~[1..3]

                    if depth.last

                        if depth.last.length > tl.length

                            (depth.length - 1).downto(0) do |i|

                                break if depth[i].length == tl.length

                                lines[line_id - 1] << "</li>\n\t</#{ lT( depth[i] ) }l>\n\t"

                                depth.pop

                            end

                        end

                        if depth.last and depth.last.length == tl.length

                            lines[line_id - 1] << '</li>'

                        end

                    end

                    unless depth.last == tl

                        depth << tl

                        atts = pba( atts )

                        atts = shelve( atts ) if atts

                        lines[line_id] = "\t<#{ lT(tl) }l#{ atts }>\n\t<li>#{ content }"

                    else

                        lines[line_id] = "\t\t<li>#{ content }"

                    end

                    last_line = line_id

                else

                    last_line = line_id

                end

                if line_id - last_line > 1 or line_id == lines.length - 1

                    depth.delete_if do |v|

                        lines[last_line] << "</li>\n\t</#{ lT( v ) }l>"

                    end

                end

            end

            lines.join( "\n" )

        end

    end

    CODE_RE = /(\W)

        @

        (?:\|(\w+?)\|)?

        (.+?)

        @

        (?=\W)/x

    def inline_textile_code( text ) 

        text.gsub!( CODE_RE ) do |m|

            before,lang,code,after = $~[1..4]

            lang = " lang=\"#{ lang }\"" if lang

            rip_offtags( "#{ before }<code#{ lang }>#{ code }</code>#{ after }" )

        end

    end

    def lT( text ) 

        text =~ /\#$/ ? 'o' : 'u'

    end

    def hard_break( text )

        text.gsub!( /(.)\n(?!\Z| *([#*=]+(\s|$)|[{|]))/, "\\1<br />" ) if hard_breaks

    end

    BLOCKS_GROUP_RE = /\n{2,}(?! )/m

    def blocks( text, deep_code = false )

        text.replace( text.split( BLOCKS_GROUP_RE ).collect do |blk|

            plain = blk !~ /\A[#*> ]/

            # skip blocks that are complex HTML

            if blk =~ /^<\/?(\w+).*>/ and not SIMPLE_HTML_TAGS.include? $1

                blk

            else

                # search for indentation levels

                blk.strip!

                if blk.empty?

                    blk

                else

                    code_blk = nil

                    blk.gsub!( /((?:\n(?:\n^ +[^\n]*)+)+)/m ) do |iblk|

                        flush_left iblk

                        blocks iblk, plain

                        iblk.gsub( /^(\S)/, "\t\\1" )

                        if plain

                            code_blk = iblk; ""

                        else

                            iblk

                        end

                    end

                    block_applied = 0 

                    @rules.each do |rule_name|

                        block_applied += 1 if ( rule_name.to_s.match /^block_/ and method( rule_name ).call( blk ) )

                    end

                    if block_applied.zero?

                        if deep_code

                            blk = "\t<pre><code>#{ blk }</code></pre>"

                        else

                            blk = "\t<p>#{ blk }</p>"

                        end

                    end

                    # hard_break blk

                    blk + "\n#{ code_blk }"

                end

            end

        end.join( "\n\n" ) )

    end

    def textile_bq( tag, atts, cite, content )

        cite, cite_title = check_refs( cite )

        cite = " cite=\"#{ cite }\"" if cite

        atts = shelve( atts ) if atts

        "\t<blockquote#{ cite }>\n\t\t<p#{ atts }>#{ content }</p>\n\t</blockquote>"

    end

    def textile_p( tag, atts, cite, content )

        atts = shelve( atts ) if atts

        "\t<#{ tag }#{ atts }>#{ content }</#{ tag }>"

    end

    alias textile_h1 textile_p

    alias textile_h2 textile_p

    alias textile_h3 textile_p

    alias textile_h4 textile_p

    alias textile_h5 textile_p

    alias textile_h6 textile_p

    def textile_fn_( tag, num, atts, cite, content )

        atts << " id=\"fn#{ num }\""

        content = "<sup>#{ num }</sup> #{ content }"

        atts = shelve( atts ) if atts

        "\t<p#{ atts }>#{ content }</p>"

    end

    BLOCK_RE = /^(([a-z]+)(\d*))(#{A}#{C})\.(?::(\S+))? (.*)$/m

    def block_textile_prefix( text ) 

        if text =~ BLOCK_RE

            tag,tagpre,num,atts,cite,content = $~[1..6]

            atts = pba( atts )

            # pass to prefix handler

            if respond_to? "textile_#{ tag }", true

                text.gsub!( $&, method( "textile_#{ tag }" ).call( tag, atts, cite, content ) )

            elsif respond_to? "textile_#{ tagpre }_", true

                text.gsub!( $&, method( "textile_#{ tagpre }_" ).call( tagpre, num, atts, cite, content ) )

            end

        end

    end

    SETEXT_RE = /\A(.+?)\n([=-])[=-]* *$/m

    def block_markdown_setext( text )

        if text =~ SETEXT_RE

            tag = if $2 == "="; "h1"; else; "h2"; end

            blk, cont = "<#{ tag }>#{ $1 }</#{ tag }>", $'

            blocks cont

            text.replace( blk + cont )

        end

    end

    ATX_RE = /\A(\#{1,6})  # $1 = string of #'s

              [ ]*

              (.+?)       # $2 = Header text

              [ ]*

              \#*         # optional closing #'s (not counted)

              $/x

    def block_markdown_atx( text )

        if text =~ ATX_RE

            tag = "h#{ $1.length }"

            blk, cont = "<#{ tag }>#{ $2 }</#{ tag }>\n\n", $'

            blocks cont

            text.replace( blk + cont )

        end

    end

    MARKDOWN_BQ_RE = /\A(^ *> ?.+$(.+\n)*\n*)+/m

    def block_markdown_bq( text )

        text.gsub!( MARKDOWN_BQ_RE ) do |blk|

            blk.gsub!( /^ *> ?/, '' )

            flush_left blk

            blocks blk

            blk.gsub!( /^(\S)/, "\t\\1" )

            "<blockquote>\n#{ blk }\n</blockquote>\n\n"

        end

    end

    MARKDOWN_RULE_RE = /^(#{

        ['*', '-', '_'].collect { |ch| '( ?' + Regexp::quote( ch ) + ' ?){3,}' }.join( '|' )

    })$/

    def block_markdown_rule( text )

        text.gsub!( MARKDOWN_RULE_RE ) do |blk|

            "<hr />"

        end

    end

    # XXX TODO XXX

    def block_markdown_lists( text )

    end

    def inline_textile_span( text ) 

        QTAGS.each do |qtag_rc, ht, qtag_re, rtype|

            text.gsub!( qtag_re ) do |m|

                case rtype

                when :limit

                    sta,qtag,atts,cite,content = $~[1..5]

                else

                    qtag,atts,cite,content = $~[1..4]

                    sta = ''

                end

                atts = pba( atts )

                atts << " cite=\"#{ cite }\"" if cite

                atts = shelve( atts ) if atts

                "#{ sta }<#{ ht }#{ atts }>#{ content }</#{ ht }>"

            end

        end

    end

    LINK_RE = /

            ([\s\[{(]|[#{PUNCT}])?     # $pre

            "                          # start

            (#{C})                     # $atts

            ([^"]+?)                   # $text

            \s?

            (?:\(([^)]+?)\)(?="))?     # $title

            ":

            (\S+?)                     # $url

            (\/)?                      # $slash

            ([^\w\/;]*?)               # $post

            (?=<|\s|$)

        /x 

    def inline_textile_link( text ) 

        text.gsub!( LINK_RE ) do |m|

            pre,atts,text,title,url,slash,post = $~[1..7]

            url, url_title = check_refs( url )

            title ||= url_title

            atts = pba( atts )

            atts = " href=\"#{ url }#{ slash }\"#{ atts }"

            atts << " title=\"#{ title }\"" if title

            atts = shelve( atts ) if atts

            external = (url =~ /^http:\/\//) ? ' class="external"' : ''

            "#{ pre }<a#{ atts }#{ external }>#{ text }</a>#{ post }"

        end

    end

    MARKDOWN_REFLINK_RE = /

            \[([^\[\]]+)\]      # $text

            [ ]?                # opt. space

            (?:\n[ ]*)?         # one optional newline followed by spaces

            \[(.*?)\]           # $id

        /x 

    def inline_markdown_reflink( text ) 

        text.gsub!( MARKDOWN_REFLINK_RE ) do |m|

            text, id = $~[1..2]

            if id.empty?

                url, title = check_refs( text )

            else

                url, title = check_refs( id )

            end

            atts = " href=\"#{ url }\""

            atts << " title=\"#{ title }\"" if title

            atts = shelve( atts )

            "<a#{ atts }>#{ text }</a>"

        end

    end

    MARKDOWN_LINK_RE = /

            \[([^\[\]]+)\]      # $text

            \(                  # open paren

            [ \t]*              # opt space

            <?(.+?)>?           # $href

            [ \t]*              # opt space

            (?:                 # whole title

            (['"])              # $quote

            (.*?)               # $title

            \3                  # matching quote

            )?                  # title is optional

            \)

        /x 

    def inline_markdown_link( text ) 

        text.gsub!( MARKDOWN_LINK_RE ) do |m|

            text, url, quote, title = $~[1..4]

            atts = " href=\"#{ url }\""

            atts << " title=\"#{ title }\"" if title

            atts = shelve( atts )

            "<a#{ atts }>#{ text }</a>"

        end

    end

    TEXTILE_REFS_RE =  /(^ *)\[([^\[\n]+?)\](#{HYPERLINK})(?=\s|$)/

    MARKDOWN_REFS_RE = /(^ *)\[([^\n]+?)\]:\s+<?(#{HYPERLINK})>?(?:\s+"((?:[^"]|\\")+)")?(?=\s|$)/m

    def refs( text )

        @rules.each do |rule_name|

            method( rule_name ).call( text ) if rule_name.to_s.match /^refs_/

        end

    end

    def refs_textile( text ) 

        text.gsub!( TEXTILE_REFS_RE ) do |m|

            flag, url = $~[2..3]

            @urlrefs[flag.downcase] = [url, nil]

            nil

        end

    end

    def refs_markdown( text )

        text.gsub!( MARKDOWN_REFS_RE ) do |m|

            flag, url = $~[2..3]

            title = $~[6]

            @urlrefs[flag.downcase] = [url, title]

            nil

        end

    end

    def check_refs( text ) 

        ret = @urlrefs[text.downcase] if text

        ret || [text, nil]

    end

    IMAGE_RE = /

            (<p>|.|^)            # start of line?

            \!                   # opening

            (\<|\=|\>)?          # optional alignment atts

            (#{C})               # optional style,class atts

            (?:\. )?             # optional dot-space

            ([^\s(!]+?)          # presume this is the src

            \s?                  # optional space

            (?:\(((?:[^\(\)]|\([^\)]+\))+?)\))?   # optional title

            \!                   # closing

            (?::#{ HYPERLINK })? # optional href

        /x 

    def inline_textile_image( text ) 

        text.gsub!( IMAGE_RE )  do |m|

            stln,algn,atts,url,title,href,href_a1,href_a2 = $~[1..8]

            atts = pba( atts )

            atts = " src=\"#{ url }\"#{ atts }"

            atts << " title=\"#{ title }\"" if title

            atts << " alt=\"#{ title }\"" 

            # size = @getimagesize($url);

            # if($size) $atts.= " $size[3]";