instiki/lib/bluecloth_tweaked.rb

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2005-08-11 07:46:38 +02:00
#!/usr/bin/env ruby
#
# Bluecloth is a Ruby implementation of Markdown, a text-to-HTML conversion
# tool.
#
# == Synopsis
#
# doc = BlueCloth::new "
# ## Test document ##
#
# Just a simple test.
# "
#
# puts doc.to_html
#
# == Authors
#
# * Michael Granger <ged@FaerieMUD.org>
#
# == Contributors
#
# * Martin Chase <stillflame@FaerieMUD.org> - Peer review, helpful suggestions
# * Florian Gross <flgr@ccan.de> - Filter options, suggestions
#
# == Copyright
#
# Original version:
# Copyright (c) 2003-2004 John Gruber
# <http://daringfireball.net/>
# All rights reserved.
#
# Ruby port:
# Copyright (c) 2004 The FaerieMUD Consortium.
#
# BlueCloth is free software; you can redistribute it and/or modify it under the
# terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# BlueCloth is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU General Public License for more details.
#
# == To-do
#
# * Refactor some of the larger uglier methods that have to do their own
# brute-force scanning because of lack of Perl features in Ruby's Regexp
# class. Alternately, could add a dependency on 'pcre' and use most Perl
# regexps.
#
# * Put the StringScanner in the render state for thread-safety.
#
# == Version
#
# $Id: bluecloth.rb,v 1.3 2004/05/02 15:56:33 webster132 Exp $
#
require 'digest/md5'
require 'logger'
require 'strscan'
### BlueCloth is a Ruby implementation of Markdown, a text-to-HTML conversion
### tool.
class BlueCloth < String
### Exception class for formatting errors.
class FormatError < RuntimeError
### Create a new FormatError with the given source +str+ and an optional
### message about the +specific+ error.
def initialize( str, specific=nil )
if specific
msg = "Bad markdown format near %p: %s" % [ str, specific ]
else
msg = "Bad markdown format near %p" % str
end
super( msg )
end
end
# Release Version
Version = '0.0.3'
# SVN Revision
SvnRev = %q$Rev: 37 $
# SVN Id tag
SvnId = %q$Id: bluecloth.rb,v 1.3 2004/05/02 15:56:33 webster132 Exp $
# SVN URL
SvnUrl = %q$URL: svn+ssh://cvs.faeriemud.org/var/svn/BlueCloth/trunk/lib/bluecloth.rb $
# Rendering state struct. Keeps track of URLs, titles, and HTML blocks
# midway through a render. I prefer this to the globals of the Perl version
# because globals make me break out in hives. Or something.
RenderState = Struct::new( "RenderState", :urls, :titles, :html_blocks, :log )
# Tab width for #detab! if none is specified
TabWidth = 4
# The tag-closing string -- set to '>' for HTML
EmptyElementSuffix = "/>";
# Table of MD5 sums for escaped characters
EscapeTable = {}
'\\`*_{}[]()#.!'.split(//).each {|char|
hash = Digest::MD5::hexdigest( char )
EscapeTable[ char ] = {
:md5 => hash,
:md5re => Regexp::new( hash ),
:re => Regexp::new( '\\\\' + Regexp::escape(char) ),
}
}
#################################################################
### I N S T A N C E M E T H O D S
#################################################################
### Create a new BlueCloth string.
def initialize( content="", *restrictions )
@log = Logger::new( $deferr )
@log.level = $DEBUG ?
Logger::DEBUG :
($VERBOSE ? Logger::INFO : Logger::WARN)
@scanner = nil
# Add any restrictions, and set the line-folding attribute to reflect
# what happens by default.
restrictions.flatten.each {|r| __send__("#{r}=", true) }
@fold_lines = true
super( content )
@log.debug "String is: %p" % self
end
######
public
######
# Filters for controlling what gets output for untrusted input. (But really,
# you're filtering bad stuff out of untrusted input at submission-time via
# untainting, aren't you?)
attr_accessor :filter_html, :filter_styles
# RedCloth-compatibility accessor. Line-folding is part of Markdown syntax,
# so this isn't used by anything.
attr_accessor :fold_lines
### Render Markdown-formatted text in this string object as HTML and return
### it. The parameter is for compatibility with RedCloth, and is currently
### unused, though that may change in the future.
def to_html( lite=false )
# Create a StringScanner we can reuse for various lexing tasks
@scanner = StringScanner::new( '' )
# Make a structure to carry around stuff that gets placeholdered out of
# the source.
rs = RenderState::new( {}, {}, {} )
# Make a copy of the string with normalized line endings, tabs turned to
# spaces, and a couple of guaranteed newlines at the end
text = self.gsub( /\r\n?/, "\n" ).detab
text += "\n\n"
@log.debug "Normalized line-endings: %p" % text
# Filter HTML if we're asked to do so
if self.filter_html
text.gsub!( "<", "&lt;" )
text.gsub!( ">", "&gt;" )
@log.debug "Filtered HTML: %p" % text
end
# Simplify blank lines
text.gsub!( /^ +$/, '' )
@log.debug "Tabs -> spaces/blank lines stripped: %p" % text
# Replace HTML blocks with placeholders
text = hide_html_blocks( text, rs )
@log.debug "Hid HTML blocks: %p" % text
@log.debug "Render state: %p" % rs
# Strip link definitions, store in render state
text = strip_link_definitions( text, rs )
@log.debug "Stripped link definitions: %p" % text
@log.debug "Render state: %p" % rs
# Escape meta-characters
text = escape_special_chars( text )
@log.debug "Escaped special characters: %p" % text
# Transform block-level constructs
text = apply_block_transforms( text, rs )
@log.debug "After block-level transforms: %p" % text
# Now swap back in all the escaped characters
text = unescape_special_chars( text )
@log.debug "After unescaping special characters: %p" % text
return text
end
### Convert tabs in +str+ to spaces.
def detab( tabwidth=TabWidth )
copy = self.dup
copy.detab!( tabwidth )
return copy
end
### Convert tabs to spaces in place and return self if any were converted.
def detab!( tabwidth=TabWidth )
newstr = self.split( /\n/ ).collect {|line|
line.gsub( /(.*?)\t/ ) do
$1 + ' ' * (tabwidth - $1.length % tabwidth)
end
}.join("\n")
self.replace( newstr )
end
#######
#private
#######
### Do block-level transforms on a copy of +str+ using the specified render
### state +rs+ and return the results.
def apply_block_transforms( str, rs )
# Port: This was called '_runBlockGamut' in the original
@log.debug "Applying block transforms to:\n %p" % str
text = transform_headers( str, rs )
text = transform_hrules( text, rs )
text = transform_lists( text, rs )
text = transform_code_blocks( text, rs )
text = transform_block_quotes( text, rs )
text = transform_auto_links( text, rs )
text = hide_html_blocks( text, rs )
text = form_paragraphs( text, rs )
@log.debug "Done with block transforms:\n %p" % text
return text
end
### Apply Markdown span transforms to a copy of the specified +str+ with the
### given render state +rs+ and return it.
def apply_span_transforms( str, rs )
@log.debug "Applying span transforms to:\n %p" % str
str = transform_code_spans( str, rs )
str = encode_html( str )
str = transform_images( str, rs )
str = transform_anchors( str, rs )
str = transform_italic_and_bold( str, rs )
# Hard breaks
str.gsub!( / {2,}\n/, "<br#{EmptyElementSuffix}\n" )
@log.debug "Done with span transforms:\n %p" % str
return str
end
# The list of tags which are considered block-level constructs and an
# alternation pattern suitable for use in regexps made from the list
BlockTags = %w[ p div h[1-6] blockquote pre table dl ol ul script ]
BlockTagPattern = BlockTags.join('|')
# Nested blocks:
# <div>
# <div>
# tags for inner block must be indented.
# </div>
# </div>
StrictBlockRegex = %r{
^ # Start of line
<(#{BlockTagPattern}) # Start tag: \2
\b # word break
(.*\n)*? # Any number of lines, minimal match
</\1> # Matching end tag
[ ]* # trailing spaces
(?=\n+|\Z) # End of line or document
}ix
# More-liberal block-matching
LooseBlockRegex = %r{
^ # Start of line
<(#{BlockTagPattern}) # start tag: \2
\b # word break
(.*\n)*? # Any number of lines, minimal match
.*</\1> # Anything + Matching end tag
[ ]* # trailing spaces
(?=\n+|\Z) # End of line or document
}ix
# Special case for <hr />.
HruleBlockRegex = %r{
( # $1
\A\n? # Start of doc + optional \n
| # or
.*\n\n # anything + blank line
)
( # save in $2
[ ]* # Any spaces
<hr # Tag open
\b # Word break
([^<>])*? # Attributes
/?> # Tag close
(?=\n\n|\Z) # followed by a blank line or end of document
)
}ix
### Replace all blocks of HTML in +str+ that start in the left margin with
### tokens.
def hide_html_blocks( str, rs )
@log.debug "Hiding HTML blocks in %p" % str
# Tokenizer proc to pass to gsub
tokenize = lambda {|match|
key = Digest::MD5::hexdigest( match )
rs.html_blocks[ key ] = match
@log.debug "Replacing %p with %p" %
[ match, key ]
"\n\n#{key}\n\n"
}
rval = str.dup
@log.debug "Finding blocks with the strict regex..."
rval.gsub!( StrictBlockRegex, &tokenize )
@log.debug "Finding blocks with the loose regex..."
rval.gsub!( LooseBlockRegex, &tokenize )
@log.debug "Finding hrules..."
rval.gsub!( HruleBlockRegex ) {|match| $1 + tokenize[$2] }
return rval
end
# Link defs are in the form: ^[id]: url "optional title"
LinkRegex = %r{
^[ ]*\[(.+)\]: # id = $1
[ ]*
\n? # maybe *one* newline
[ ]*
(\S+) # url = $2
[ ]*
\n? # maybe one newline
[ ]*
(?:
# Titles are delimited by "quotes" or (parens).
["(]
(.+?) # title = $3
[")] # Matching ) or "
[ ]*
)? # title is optional
(?:\n+|\Z)
}x
### Strip link definitions from +str+, storing them in the given RenderState
### +rs+.
def strip_link_definitions( str, rs )
str.gsub( LinkRegex ) {|match|
id, url, title = $1, $2, $3
rs.urls[ id.downcase ] = encode_html( url )
unless title.nil?
rs.titles[ id.downcase ] = title.gsub( /"/, "&quot;" )
end
""
}
end
### Escape special characters in the given +str+
def escape_special_chars( str )
@log.debug " Escaping special characters"
text = ''
tokenize_html( str ) {|token, str|
@log.debug " Adding %p token %p" % [ token, str ]
case token
# Within tags, encode * and _
when :tag
text += str.
gsub( /\*/, EscapeTable['*'][:md5] ).
gsub( /_/, EscapeTable['_'][:md5] )
# Encode backslashed stuff in regular text
when :text
text += encode_backslash_escapes( str )
else
raise TypeError, "Unknown token type %p" % token
end
}
@log.debug " Text with escapes is now: %p" % text
return text
end
### Swap escaped special characters in a copy of the given +str+ and return
### it.
def unescape_special_chars( str )
EscapeTable.each {|char, hash|
@log.debug "Unescaping escaped %p with %p" %
[ char, hash[:md5re] ]
str.gsub!( hash[:md5re], char )
}
return str
end
### Return a copy of the given +str+ with any backslashed special character
### in it replaced with MD5 placeholders.
def encode_backslash_escapes( str )
# Make a copy with any double-escaped backslashes encoded
text = str.gsub( /\\\\/, EscapeTable['\\'][:md5] )
EscapeTable.each_pair {|char, esc|
next if char == '\\'
text.gsub!( esc[:re], esc[:md5] )
}
return text
end
### Transform any Markdown-style horizontal rules in a copy of the specified
### +str+ and return it.
def transform_hrules( str, rs )
@log.debug " Transforming horizontal rules"
str.gsub( /^( ?[\-\*] ?){3,}$/, "\n<hr#{EmptyElementSuffix}\n" )
end
# Pattern to transform lists
ListRegexp = %r{
(?:
^[ ]{0,#{TabWidth - 1}} # Indent < tab width
(\*|\d+\.) # unordered or ordered ($1)
[ ]+ # At least one space
)
(?m:.+?) # item content (include newlines)
(?:
\z # Either EOF
| # or
\n{2,} # Blank line...
(?=\S) # ...followed by non-space
(?![ ]* (\*|\d+\.) [ ]+) # ...but not another item
)
}x
### Transform Markdown-style lists in a copy of the specified +str+ and
### return it.
def transform_lists( str, rs )
@log.debug " Transforming lists at %p" % (str[0,100] + '...')
str.gsub( ListRegexp ) {|list|
@log.debug " Found list %p" % list
list_type = ($1 == '*' ? "ul" : "ol")
list.gsub!( /\n{2,}/, "\n\n\n" )
%{<%s>\n%s</%s>\n} % [
list_type,
transform_list_items( list, rs ),
list_type,
]
}
end
# Pattern for transforming list items
ListItemRegexp = %r{
(\n)? # leading line = $1
(^[ ]*) # leading whitespace = $2
(\*|\d+\.) [ ]+ # list marker = $3
((?m:.+?) # list item text = $4
(\n{1,2}))
(?= \n* (\z | \2 (\*|\d+\.) [ ]+))
}x
### Transform list items in a copy of the given +str+ and return it.
def transform_list_items( str, rs )
@log.debug " Transforming list items"
# Trim trailing blank lines
str = str.sub( /\n{2,}\z/, "\n" )
str.gsub( ListItemRegexp ) {|line|
@log.debug " Found item line %p" % line
leading_line, item = $1, $4
if leading_line or /\n{2,}/.match( item )
@log.debug " Found leading line or item has a blank"
item = apply_block_transforms( outdent(item), rs )
else
# Recursion for sub-lists
@log.debug " Recursing for sublist"
item = transform_lists( outdent(item), rs ).chomp
item = apply_span_transforms( item, rs )
end
%{<li>%s</li>\n} % item
}
end
# Pattern for matching codeblocks
CodeBlockRegexp = %r{
(.?) # $1 = preceding character
:\n+ # colon + NL delimiter
( # $2 = the code block
(?:
(?:[ ]{#{TabWidth}} | \t) # a tab or tab-width of spaces
.*\n+
)+
)
((?=^[ ]{0,#{TabWidth}}\S)|\Z) # Lookahead for non-space at
# line-start, or end of doc
}x
### Transform Markdown-style codeblocks in a copy of the specified +str+ and
### return it.
def transform_code_blocks( str, rs )
@log.debug " Transforming code blocks"
str.gsub( CodeBlockRegexp ) {|block|
prevchar, codeblock = $1, $2
@log.debug " prevchar = %p" % prevchar
# Generated the codeblock
%{%s\n\n<pre><code>%s\n</code></pre>\n\n} % [
(prevchar.empty? || /\s/ =~ prevchar) ? "" : "#{prevchar}:",
encode_code( outdent(codeblock), rs ).rstrip,
]
}
end
# Pattern for matching Markdown blockquote blocks
BlockQuoteRegexp = %r{
(?:
^[ ]*>[ ]? # '>' at the start of a line
.+\n # rest of the first line
(?:.+\n)* # subsequent consecutive lines
\n* # blanks
)+
}x
### Transform Markdown-style blockquotes in a copy of the specified +str+
### and return it.
def transform_block_quotes( str, rs )
@log.debug " Transforming block quotes"
str.gsub( BlockQuoteRegexp ) {|quote|
@log.debug "Making blockquote from %p" % quote
quote.gsub!( /^[ ]*>[ ]?/, '' )
%{<blockquote>\n%s\n</blockquote>\n\n} %
apply_block_transforms( quote, rs ).
gsub( /^/, " " * TabWidth )
}
end
AutoAnchorURLRegexp = /<((https?|ftp):[^'">\s]+)>/
AutoAnchorEmailRegexp = %r{
<
(
[-.\w]+
\@
[-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+
)
>
}x
### Transform URLs in a copy of the specified +str+ into links and return
### it.
def transform_auto_links( str, rs )
@log.debug " Transforming auto-links"
str.gsub( AutoAnchorURLRegexp, %{<a href="\\1">\\1</a>}).
gsub( AutoAnchorEmailRegexp ) {|addr|
encode_email_address( unescape_special_chars($1) )
}
end
# Encoder functions to turn characters of an email address into encoded
# entities.
Encoders = [
lambda {|char| "&#%03d;" % char},
lambda {|char| "&#x%X;" % char},
lambda {|char| char.chr },
]
### Transform a copy of the given email +addr+ into an escaped version safer
### for posting publicly.
def encode_email_address( addr )
rval = ''
("mailto:" + addr).each_byte {|b|
case b
when ?:
rval += ":"
when ?@
rval += Encoders[ rand(2) ][ b ]
else
r = rand(100)
rval += (
r > 90 ? Encoders[2][ b ] :
r < 45 ? Encoders[1][ b ] :
Encoders[0][ b ]
)
end
}
return %{<a href="%s">%s</a>} % [ rval, rval.sub(/.+?:/, '') ]
end
# Regex for matching Setext-style headers
SetextHeaderRegexp = %r{
(.+) # The title text ($1)
\n
([\-=])+ # Match a line of = or -. Save only one in $2.
[ ]*\n+
}x
# Regexp for matching ATX-style headers
AtxHeaderRegexp = %r{
^(\#{1,6}) # $1 = string of #'s
[ ]*
(.+?) # $2 = Header text
[ ]*
\#* # optional closing #'s (not counted)
\n+
}x
### Apply Markdown header transforms to a copy of the given +str+ amd render
### state +rs+ and return the result.
def transform_headers( str, rs )
@log.debug " Transforming headers"
# Setext-style headers:
# Header 1
# ========
#
# Header 2
# --------
#
str.
gsub( SetextHeaderRegexp ) {|m|
@log.debug "Found setext-style header"
title, hdrchar = $1, $2
title = apply_span_transforms( title, rs )
case hdrchar
when '='
%[<h1>#{title}</h1>\n\n]
when '-'
%[<h2>#{title}</h2>\n\n]
else
title
end
}.
gsub( AtxHeaderRegexp ) {|m|
@log.debug "Found ATX-style header"
hdrchars, title = $1, $2
title = apply_span_transforms( title, rs )
level = hdrchars.length
%{<h%d>%s</h%d>\n\n} % [ level, title, level ]
}
end
### Wrap all remaining paragraph-looking text in a copy of +str+ inside <p>
### tags and return it.
def form_paragraphs( str, rs )
@log.debug " Forming paragraphs"
grafs = str.
sub( /\A\n+/, '' ).
sub( /\n+\z/, '' ).
split( /\n{2,}/ )
rval = grafs.collect {|graf|
# Unhashify HTML blocks if this is a placeholder
if rs.html_blocks.key?( graf )
rs.html_blocks[ graf ]
# Otherwise, wrap in <p> tags
else
apply_span_transforms(graf, rs).
sub( /^[ ]*/, '<p>' ) + '</p>'
end
}.join( "\n\n" )
@log.debug " Formed paragraphs: %p" % rval
return rval
end
# Pattern to match the linkid part of an anchor tag for reference-style
# links.
RefLinkIdRegex = %r{
[ ]? # Optional leading space
(?:\n[ ]*)? # Optional newline + spaces
\[
(.*?) # Id = $1
\]
}x
InlineLinkRegex = %r{
\( # Literal paren
[ ]* # Zero or more spaces
(.*?) # URI = $1
[ ]* # Zero or more spaces
(?: #
([\"\']) # Opening quote char = $2
(.*?) # Title = $3
\2 # Matching quote char
)? # Title is optional
\)
}x
### Apply Markdown anchor transforms to a copy of the specified +str+ with
### the given render state +rs+ and return it.
def transform_anchors( str, rs )
@log.debug " Transforming anchors"
@scanner.string = str.dup
text = ''
# Scan the whole string
until @scanner.empty?
if @scanner.scan( /\[/ )
link = ''; linkid = ''
depth = 1
startpos = @scanner.pos
@log.debug " Found a bracket-open at %d" % startpos
# Scan the rest of the tag, allowing unlimited nested []s. If
# the scanner runs out of text before the opening bracket is
# closed, append the text and return (wasn't a valid anchor).
while depth.nonzero?
linktext = @scanner.scan_until( /\]|\[/ )
if linktext
@log.debug " Found a bracket at depth %d: %p" %
[ depth, linktext ]
link += linktext
# Decrement depth for each closing bracket
depth += ( linktext[-1, 1] == ']' ? -1 : 1 )
@log.debug " Depth is now #{depth}"
# If there's no more brackets, it must not be an anchor, so
# just abort.
else
@log.debug " Missing closing brace, assuming non-link."
link += @scanner.rest
@scanner.terminate
return text + '[' + link
end
end
link.slice!( -1 ) # Trim final ']'
@log.debug " Found leading link %p" % link
# Look for a reference-style second part
if @scanner.scan( RefLinkIdRegex )
linkid = @scanner[1]
linkid = link.dup if linkid.empty?
linkid.downcase!
@log.debug " Found a linkid: %p" % linkid
# If there's a matching link in the link table, build an
# anchor tag for it.
if rs.urls.key?( linkid )
@log.debug " Found link key in the link table: %p" %
rs.urls[linkid]
url = escape_md( rs.urls[linkid] )
text += %{<a href="#{url}"}
if rs.titles.key?(linkid)
text += %{ title="%s"} % escape_md( rs.titles[linkid] )
end
text += %{>#{link}</a>}
# If the link referred to doesn't exist, just append the raw
# source to the result
else
@log.debug " Linkid %p not found in link table" % linkid
@log.debug " Appending original string instead: %p" %
@scanner.string[ startpos-1 .. @scanner.pos ]
text += @scanner.string[ startpos-1 .. @scanner.pos ]
end
# ...or for an inline style second part
elsif @scanner.scan( InlineLinkRegex )
url = @scanner[1]
title = @scanner[3]
@log.debug " Found an inline link to %p" % url
text += %{<a href="%s"} % escape_md( url )
if title
text += %{ title="%s"} % escape_md( title )
end
text += %{>#{link}</a>}
# No linkid part: just append the first part as-is.
else
@log.debug "No linkid, so no anchor. Appending literal text."
text += @scanner.string[ startpos-1 .. @scanner.pos-1 ]
end # if linkid
# Plain text
else
@log.debug " Scanning to the next link from %p" % @scanner.rest
text += @scanner.scan( /[^\[]+/ )
end
end # until @scanner.empty?
return text
end
# Pattern to match strong emphasis in Markdown text
BoldRegexp = %r{ (\*\*|__) (?=\S) (.+?\S) \1 }x
# Pattern to match normal emphasis in Markdown text
ItalicRegexp = %r{ (\*|_) (?=\S) (.+?\S) \1 }x
### Transform italic- and bold-encoded text in a copy of the specified +str+
### and return it.
def transform_italic_and_bold( str, rs )
@log.debug " Transforming italic and bold"
str.
gsub( BoldRegexp, %{<strong>\\2</strong>} ).
gsub( ItalicRegexp, %{<em>\\2</em>} )
end
### Transform backticked spans into <code> spans.
def transform_code_spans( str, rs )
@log.debug " Transforming code spans"
# Set up the string scanner and just return the string unless there's at
# least one backtick.
@scanner.string = str.dup
unless @scanner.exist?( /`/ )
@scanner.terminate
@log.debug "No backticks found for code span in %p" % str
return str
end
@log.debug "Transforming code spans in %p" % str
# Build the transformed text anew
text = ''
# Scan to the end of the string
until @scanner.empty?
# Scan up to an opening backtick
if pre = @scanner.scan_until( /.?(?=`)/m )
text += pre
@log.debug "Found backtick at %d after '...%s'" %
[ @scanner.pos, text[-10, 10] ]
# Make a pattern to find the end of the span
opener = @scanner.scan( /`+/ )
len = opener.length
closer = Regexp::new( opener )
@log.debug "Scanning for end of code span with %p" % closer
# Scan until the end of the closing backtick sequence. Chop the
# backticks off the resultant string, strip leading and trailing
# whitespace, and encode any enitites contained in it.
codespan = @scanner.scan_until( closer ) or
raise FormatError::new( @scanner.rest[0,20],
"No %p found before end" % opener )
@log.debug "Found close of code span at %d: %p" %
[ @scanner.pos - len, codespan ]
codespan.slice!( -len, len )
text += "<code>%s</code>" %
encode_code( codespan.strip, rs )
# If there's no more backticks, just append the rest of the string
# and move the scan pointer to the end
else
text += @scanner.rest
@scanner.terminate
end
end
return text
end
# Next, handle inline images: ![alt text](url "optional title")
# Don't forget: encode * and _
InlineImageRegexp = %r{
( # Whole match = $1
!\[ (.*?) \] # alt text = $2
\([ ]* (\S+) [ ]* # source url = $3
( # title = $4
(["']) # quote char = $5
.*?
\5 # matching quote
[ ]*
)? # title is optional
\)
)
}xs #"
# Reference-style images
ReferenceImageRegexp = %r{
( # Whole match = $1
!\[ (.*?) \] # Alt text = $2
[ ]? # Optional space
(?:\n[ ]*)? # One optional newline + spaces
\[ (.*?) \] # id = $3
)
}xs
### Turn image markup into image tags.
def transform_images( str, rs )
@log.debug " Transforming images" % str
# Handle reference-style labeled images: ![alt text][id]
str.
gsub( ReferenceImageRegexp ) {|match|
whole, alt, linkid = $1, $2, $3.downcase
@log.debug "Matched %p" % match
res = nil
# for shortcut links like ![this][].
linkid = alt.downcase if linkid.empty?
if rs.urls.key?( linkid )
url = escape_md( rs.urls[linkid] )
@log.debug "Found url '%s' for linkid '%s' " %
[ url, linkid ]
# Build the tag
result = %{<img src="%s" alt="%s"} % [ url, alt ]
if rs.titles.key?( linkid )
result += %{ title="%s"} % escape_md( rs.titles[linkid] )
end
result += EmptyElementSuffix
else
result = whole
end
@log.debug "Replacing %p with %p" %
[ match, result ]
result
}.
# Inline image style
gsub( InlineImageRegexp ) {|match|
@log.debug "Found inline image %p" % match
whole, alt, title = $1, $2, $4
url = escape_md( $3 )
# Build the tag
result = %{<img src="%s" alt="%s"} % [ url, alt ]
unless title.nil?
result += %{ title="%s"} % escape_md( title.gsub(/^"|"$/, '') )
end
result += EmptyElementSuffix
@log.debug "Replacing %p with %p" %
[ match, result ]
result
}
end
# Regexp to match special characters in a code block
CodeEscapeRegexp = %r{( \* | _ | \{ | \} | \[ | \] )}x
### Escape any characters special to HTML and encode any characters special
### to Markdown in a copy of the given +str+ and return it.
def encode_code( str, rs )
str.gsub( %r{&}, '&amp;' ).
gsub( %r{<}, '&lt;' ).
gsub( %r{>}, '&gt;' ).
gsub( CodeEscapeRegexp ) {|match| EscapeTable[match][:md5]}
end
#################################################################
### U T I L I T Y F U N C T I O N S
#################################################################
### Escape any markdown characters in a copy of the given +str+ and return
### it.
def escape_md( str )
str.
gsub( /\*/, '&#42;' ).
gsub( /_/, '&#95;' )
end
# Matching constructs for tokenizing X/HTML
HTMLCommentRegexp = %r{ <! ( -- .*? -- \s* )+ > }mx
XMLProcInstRegexp = %r{ <\? .*? \?> }mx
MetaTag = Regexp::union( HTMLCommentRegexp, XMLProcInstRegexp )
HTMLTagOpenRegexp = %r{ < [a-z/!$] [^<>]* }mx
HTMLTagCloseRegexp = %r{ > }x
HTMLTagPart = Regexp::union( HTMLTagOpenRegexp, HTMLTagCloseRegexp )
### Break the HTML source in +str+ into a series of tokens and return
### them. The tokens are just 2-element Array tuples with a type and the
### actual content. If this function is called with a block, the type and
### text parts of each token will be yielded to it one at a time as they are
### extracted.
def tokenize_html( str )
depth = 0
tokens = []
@scanner.string = str.dup
type, token = nil, nil
until @scanner.empty?
@log.debug "Scanning from %p" % @scanner.rest
# Match comments and PIs without nesting
if (( token = @scanner.scan(MetaTag) ))
type = :tag
# Do nested matching for HTML tags
elsif (( token = @scanner.scan(HTMLTagOpenRegexp) ))
tagstart = @scanner.pos
@log.debug " Found the start of a plain tag at %d" % tagstart
# Start the token with the opening angle
depth = 1
type = :tag
# Scan the rest of the tag, allowing unlimited nested <>s. If
# the scanner runs out of text before the tag is closed, raise
# an error.
while depth.nonzero?
# Scan either an opener or a closer
chunk = @scanner.scan( HTMLTagPart ) or
raise "Malformed tag at character %d: %p" %
[ tagstart, token + @scanner.rest ]
@log.debug " Found another part of the tag at depth %d: %p" %
[ depth, chunk ]
token += chunk
# If the last character of the token so far is a closing
# angle bracket, decrement the depth. Otherwise increment
# it for a nested tag.
depth += ( token[-1, 1] == '>' ? -1 : 1 )
@log.debug " Depth is now #{depth}"
end
# Match text segments
else
@log.debug " Looking for a chunk of text"
type = :text
# Scan forward, always matching at least one character to move
# the pointer beyond any non-tag '<'.
token = @scanner.scan_until( /[^<]+/m )
end
@log.debug " type: %p, token: %p" % [ type, token ]
# If a block is given, feed it one token at a time. Add the token to
# the token list to be returned regardless.
if block_given?
yield( type, token )
end
tokens << [ type, token ]
end
return tokens
end
### Return a copy of +str+ with angle brackets and ampersands HTML-encoded.
def encode_html( str )
str.gsub( /&(?!#?[x]?(?:[0-9a-f]+|\w{1,8});)/i, "&amp;" ).
gsub( %r{<(?![a-z/?\$!])}i, "&lt;" )
end
### Return one level of line-leading tabs or spaces from a copy of +str+ and
### return it.
def outdent( str )
str.gsub( /^(\t|[ ]{1,#{TabWidth}})/, '')
end
end # class BlueCloth