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Diffstat (limited to 'lib/rdoc/markup.rb')
| -rw-r--r-- | lib/rdoc/markup.rb | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/lib/rdoc/markup.rb b/lib/rdoc/markup.rb new file mode 100644 index 0000000000..46654ebb58 --- /dev/null +++ b/lib/rdoc/markup.rb @@ -0,0 +1,466 @@ +require 'rdoc' + +## +# RDoc::Markup parses plain text documents and attempts to decompose them into +# their constituent parts. Some of these parts are high-level: paragraphs, +# chunks of verbatim text, list entries and the like. Other parts happen at +# the character level: a piece of bold text, a word in code font. This markup +# is similar in spirit to that used on WikiWiki webs, where folks create web +# pages using a simple set of formatting rules. +# +# RDoc::Markup itself does no output formatting: this is left to a different +# set of classes. +# +# RDoc::Markup is extendable at runtime: you can add new markup elements to be +# recognised in the documents that RDoc::Markup parses. +# +# RDoc::Markup is intended to be the basis for a family of tools which share +# the common requirement that simple, plain-text should be rendered in a +# variety of different output formats and media. It is envisaged that +# RDoc::Markup could be the basis for formating RDoc style comment blocks, +# Wiki entries, and online FAQs. +# +# = Basic Formatting +# +# * RDoc::Markup looks for a document's natural left margin. This is +# used as the initial margin for the document. +# +# * Consecutive lines starting at this margin are considered to be a +# paragraph. +# +# * If a paragraph starts with a "*", "-", or with "<digit>.", then it is +# taken to be the start of a list. The margin in increased to be the +# first non-space following the list start flag. Subsequent lines +# should be indented to this new margin until the list ends. For +# example: +# +# * this is a list with three paragraphs in +# the first item. This is the first paragraph. +# +# And this is the second paragraph. +# +# 1. This is an indented, numbered list. +# 2. This is the second item in that list +# +# This is the third conventional paragraph in the +# first list item. +# +# * This is the second item in the original list +# +# * You can also construct labeled lists, sometimes called description +# or definition lists. Do this by putting the label in square brackets +# and indenting the list body: +# +# [cat] a small furry mammal +# that seems to sleep a lot +# +# [ant] a little insect that is known +# to enjoy picnics +# +# A minor variation on labeled lists uses two colons to separate the +# label from the list body: +# +# cat:: a small furry mammal +# that seems to sleep a lot +# +# ant:: a little insect that is known +# to enjoy picnics +# +# This latter style guarantees that the list bodies' left margins are +# aligned: think of them as a two column table. +# +# * Any line that starts to the right of the current margin is treated +# as verbatim text. This is useful for code listings. The example of a +# list above is also verbatim text. +# +# * A line starting with an equals sign (=) is treated as a +# heading. Level one headings have one equals sign, level two headings +# have two,and so on. +# +# * A line starting with three or more hyphens (at the current indent) +# generates a horizontal rule. The more hyphens, the thicker the rule +# (within reason, and if supported by the output device) +# +# * You can use markup within text (except verbatim) to change the +# appearance of parts of that text. Out of the box, RDoc::Markup +# supports word-based and general markup. +# +# Word-based markup uses flag characters around individual words: +# +# [\*word*] displays word in a *bold* font +# [\_word_] displays word in an _emphasized_ font +# [\+word+] displays word in a +code+ font +# +# General markup affects text between a start delimiter and and end +# delimiter. Not surprisingly, these delimiters look like HTML markup. +# +# [\<b>text...</b>] displays word in a *bold* font +# [\<em>text...</em>] displays word in an _emphasized_ font +# [\<i>text...</i>] displays word in an _emphasized_ font +# [\<tt>text...</tt>] displays word in a +code+ font +# +# Unlike conventional Wiki markup, general markup can cross line +# boundaries. You can turn off the interpretation of markup by +# preceding the first character with a backslash, so \\\<b>bold +# text</b> and \\\*bold* produce \<b>bold text</b> and \*bold +# respectively. +# +# * Hyperlinks to the web starting http:, mailto:, ftp:, or www. are +# recognized. An HTTP url that references an external image file is +# converted into an inline <IMG..>. Hyperlinks starting 'link:' are +# assumed to refer to local files whose path is relative to the --op +# directory. +# +# Hyperlinks can also be of the form <tt>label</tt>[url], in which +# case the label is used in the displayed text, and <tt>url</tt> is +# used as the target. If <tt>label</tt> contains multiple words, +# put it in braces: <em>{multi word label}[</em>url<em>]</em>. +# +# == Synopsis +# +# This code converts <tt>input_string</tt> to HTML. The conversion +# takes place in the +convert+ method, so you can use the same +# RDoc::Markup object to convert multiple input strings. +# +# require 'rdoc/markup' +# require 'rdoc/markup/to_html' +# +# p = RDoc::Markup.new +# h = RDoc::Markup::ToHtml.new +# +# puts p.convert(input_string, h) +# +# You can extend the RDoc::Markup parser to recognise new markup +# sequences, and to add special processing for text that matches a +# regular epxression. Here we make WikiWords significant to the parser, +# and also make the sequences {word} and \<no>text...</no> signify +# strike-through text. When then subclass the HTML output class to deal +# with these: +# +# require 'rdoc/markup' +# require 'rdoc/markup/to_html' +# +# class WikiHtml < RDoc::Markup::ToHtml +# def handle_special_WIKIWORD(special) +# "<font color=red>" + special.text + "</font>" +# end +# end +# +# p = RDoc::Markup.new +# p.add_word_pair("{", "}", :STRIKE) +# p.add_html("no", :STRIKE) +# +# p.add_special(/\b([A-Z][a-z]+[A-Z]\w+)/, :WIKIWORD) +# +# h = WikiHtml.new +# h.add_tag(:STRIKE, "<strike>", "</strike>") +# +# puts "<body>" + p.convert(ARGF.read, h) + "</body>" +# +#-- +# Author:: Dave Thomas, dave@pragmaticprogrammer.com +# Version:: 0.0 +# License:: Ruby license + +class RDoc::Markup + + SPACE = ?\s + + # List entries look like: + # * text + # 1. text + # [label] text + # label:: text + # + # Flag it as a list entry, and work out the indent for subsequent lines + + SIMPLE_LIST_RE = /^( + ( \* (?# bullet) + |- (?# bullet) + |\d+\. (?# numbered ) + |[A-Za-z]\. (?# alphabetically numbered ) + ) + \s+ + )\S/x + + LABEL_LIST_RE = /^( + ( \[.*?\] (?# labeled ) + |\S.*:: (?# note ) + )(?:\s+|$) + )/x + + ## + # Take a block of text and use various heuristics to determine it's + # structure (paragraphs, lists, and so on). Invoke an event handler as we + # identify significant chunks. + + def initialize + @am = AttributeManager.new + @output = nil + end + + ## + # Add to the sequences used to add formatting to an individual word (such + # as *bold*). Matching entries will generate attibutes that the output + # formatters can recognize by their +name+. + + def add_word_pair(start, stop, name) + @am.add_word_pair(start, stop, name) + end + + ## + # Add to the sequences recognized as general markup. + + def add_html(tag, name) + @am.add_html(tag, name) + end + + ## + # Add to other inline sequences. For example, we could add WikiWords using + # something like: + # + # parser.add_special(/\b([A-Z][a-z]+[A-Z]\w+)/, :WIKIWORD) + # + # Each wiki word will be presented to the output formatter via the + # accept_special method. + + def add_special(pattern, name) + @am.add_special(pattern, name) + end + + ## + # We take a string, split it into lines, work out the type of each line, + # and from there deduce groups of lines (for example all lines in a + # paragraph). We then invoke the output formatter using a Visitor to + # display the result. + + def convert(str, op) + @lines = Lines.new(str.split(/\r?\n/).collect { |aLine| + Line.new(aLine) }) + return "" if @lines.empty? + @lines.normalize + assign_types_to_lines + group = group_lines + # call the output formatter to handle the result + # group.to_a.each {|i| p i} + group.accept(@am, op) + end + + private + + ## + # Look through the text at line indentation. We flag each line as being + # Blank, a paragraph, a list element, or verbatim text. + + def assign_types_to_lines(margin = 0, level = 0) + + while line = @lines.next + if line.isBlank? + line.stamp(Line::BLANK, level) + next + end + + # if a line contains non-blanks before the margin, then it must belong + # to an outer level + + text = line.text + + for i in 0...margin + if text[i] != SPACE + @lines.unget + return + end + end + + active_line = text[margin..-1] + + # Rules (horizontal lines) look like + # + # --- (three or more hyphens) + # + # The more hyphens, the thicker the rule + # + + if /^(---+)\s*$/ =~ active_line + line.stamp(Line::RULE, level, $1.length-2) + next + end + + # Then look for list entries. First the ones that have to have + # text following them (* xxx, - xxx, and dd. xxx) + + if SIMPLE_LIST_RE =~ active_line + + offset = margin + $1.length + prefix = $2 + prefix_length = prefix.length + + flag = case prefix + when "*","-" then ListBase::BULLET + when /^\d/ then ListBase::NUMBER + when /^[A-Z]/ then ListBase::UPPERALPHA + when /^[a-z]/ then ListBase::LOWERALPHA + else raise "Invalid List Type: #{self.inspect}" + end + + line.stamp(Line::LIST, level+1, prefix, flag) + text[margin, prefix_length] = " " * prefix_length + assign_types_to_lines(offset, level + 1) + next + end + + + if LABEL_LIST_RE =~ active_line + offset = margin + $1.length + prefix = $2 + prefix_length = prefix.length + + next if handled_labeled_list(line, level, margin, offset, prefix) + end + + # Headings look like + # = Main heading + # == Second level + # === Third + # + # Headings reset the level to 0 + + if active_line[0] == ?= and active_line =~ /^(=+)\s*(.*)/ + prefix_length = $1.length + prefix_length = 6 if prefix_length > 6 + line.stamp(Line::HEADING, 0, prefix_length) + line.strip_leading(margin + prefix_length) + next + end + + # If the character's a space, then we have verbatim text, + # otherwise + + if active_line[0] == SPACE + line.strip_leading(margin) if margin > 0 + line.stamp(Line::VERBATIM, level) + else + line.stamp(Line::PARAGRAPH, level) + end + end + end + + ## + # Handle labeled list entries, We have a special case to deal with. + # Because the labels can be long, they force the remaining block of text + # over the to right: + # + # this is a long label that I wrote:: and here is the + # block of text with + # a silly margin + # + # So we allow the special case. If the label is followed by nothing, and + # if the following line is indented, then we take the indent of that line + # as the new margin. + # + # this is a long label that I wrote:: + # here is a more reasonably indented block which + # will be attached to the label. + # + + def handled_labeled_list(line, level, margin, offset, prefix) + prefix_length = prefix.length + text = line.text + flag = nil + case prefix + when /^\[/ + flag = ListBase::LABELED + prefix = prefix[1, prefix.length-2] + when /:$/ + flag = ListBase::NOTE + prefix.chop! + else raise "Invalid List Type: #{self.inspect}" + end + + # body is on the next line + + if text.length <= offset + original_line = line + line = @lines.next + return(false) unless line + text = line.text + + for i in 0..margin + if text[i] != SPACE + @lines.unget + return false + end + end + i = margin + i += 1 while text[i] == SPACE + if i >= text.length + @lines.unget + return false + else + offset = i + prefix_length = 0 + @lines.delete(original_line) + end + end + + line.stamp(Line::LIST, level+1, prefix, flag) + text[margin, prefix_length] = " " * prefix_length + assign_types_to_lines(offset, level + 1) + return true + end + + ## + # Return a block consisting of fragments which are paragraphs, list + # entries or verbatim text. We merge consecutive lines of the same type + # and level together. We are also slightly tricky with lists: the lines + # following a list introduction look like paragraph lines at the next + # level, and we remap them into list entries instead. + + def group_lines + @lines.rewind + + inList = false + wantedType = wantedLevel = nil + + block = LineCollection.new + group = nil + + while line = @lines.next + if line.level == wantedLevel and line.type == wantedType + group.add_text(line.text) + else + group = block.fragment_for(line) + block.add(group) + if line.type == Line::LIST + wantedType = Line::PARAGRAPH + else + wantedType = line.type + end + wantedLevel = line.type == Line::HEADING ? line.param : line.level + end + end + + block.normalize + block + end + + ## + # For debugging, we allow access to our line contents as text. + + def content + @lines.as_text + end + public :content + + ## + # For debugging, return the list of line types. + + def get_line_types + @lines.line_types + end + public :get_line_types + +end + +require 'rdoc/markup/fragments' +require 'rdoc/markup/lines' |