Import RDoc 2.2.1 r185

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@19537 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rdoc/parser/perl.rb

@@ -0,0 +1,165 @@
+require 'rdoc/parser'
+
+##
+#
+# This is an attamept to write a basic parser for Perl's
+# POD (Plain old Documentation) format.  Ruby code must
+# co-exist with Perl, and some tasks are easier in Perl
+# than Ruby because of existing libraries.
+#
+# One difficult is that Perl POD has no means of identifying
+# the classes (packages) and methods (subs) with which it
+# is associated, it is more like literate programming in so
+# far as it just happens to be in the same place as the code,
+# but need not be.
+#
+# We would like to support all the markup the POD provides
+# so that it will convert happily to HTML.  At the moment
+# I don't think I can do that: time constraints. 
+#
+
+class RDoc::Parser::PerlPOD < RDoc::Parser
+
+  parse_files_matching(/.p[lm]$/)
+
+  ##
+  # Prepare to parse a perl file
+
+  def initialize(top_level, file_name, content, options, stats)
+    super
+
+    preprocess = RDoc::Markup::PreProcess.new @file_name, @options.rdoc_include
+
+    preprocess.handle @content do |directive, param|
+      warn "Unrecognized directive '#{directive}' in #{@file_name}"
+    end
+  end
+
+  ##
+  # Extract the Pod(-like) comments from the code.
+  # At its most basic there will ne no need to distinguish
+  # between the different types of header, etc.
+  #
+  # This uses a simple finite state machine, in a very
+  # procedural pattern. I could "replace case with polymorphism"
+  # but I think it would obscure the intent, scatter the
+  # code all over tha place.  This machine is necessary
+  # because POD requires that directives be preceded by
+  # blank lines, so reading line by line is necessary, 
+  # and preserving state about what is seen is necesary.
+
+  def scan
+
+    @top_level.comment ||= ""
+    state=:code_blank    
+    line_number = 0
+    line = nil
+
+    # This started out as a really long nested case statement,
+    # which also led to repetitive code.  I'd like to avoid that
+    # so I'm using a "table" instead.
+    
+    # Firstly we need some procs to do the transition and processing
+    # work.  Because these are procs they are closures, and they can
+    # use variables in the local scope.
+    #
+    # First, the "nothing to see here" stuff.
+    code_noop = lambda do 
+      if line =~ /^\s+$/
+	state = :code_blank
+      end
+    end
+
+    pod_noop = lambda do 
+      if line =~ /^\s+$/
+	state = :pod_blank
+      end
+      @top_level.comment += filter(line)
+    end
+
+    begin_noop = lambda do 
+      if line =~ /^\s+$/
+	state = :begin_blank
+      end
+      @top_level.comment += filter(line)
+    end
+
+    # Now for the blocks that process code and comments...
+
+    transit_to_pod = lambda do
+      case line
+      when /^=(?:pod|head\d+)/
+	state = :pod_no_blank
+	@top_level.comment += filter(line)
+      when /^=over/
+	state = :over_no_blank
+	@top_level.comment += filter(line)
+      when /^=(?:begin|for)/
+	state = :begin_no_blank
+      end
+    end
+
+    process_pod = lambda do
+      case line
+      when  /^\s*$/
+	state = :pod_blank
+	@top_level.comment += filter(line)
+      when /^=cut/
+	state = :code_no_blank
+      when /^=end/
+	$stderr.puts "'=end' unexpected at #{line_number} in #{@file_name}"
+      else
+	@top_level.comment += filter(line)
+      end
+    end
+
+
+    process_begin = lambda do
+      case line
+      when  /^\s*$/
+	state = :begin_blank
+	@top_level.comment += filter(line)
+      when /^=end/
+	state = :code_no_blank
+      when /^=cut/
+	$stderr.puts "'=cut' unexpected at #{line_number} in #{@file_name}"
+      else
+	@top_level.comment += filter(line)
+      end
+
+    end
+
+
+    transitions = { :code_no_blank => code_noop,
+                    :code_blank => transit_to_pod,
+		    :pod_no_blank => pod_noop,
+		    :pod_blank => process_pod,
+		    :begin_no_blank => begin_noop,
+		    :begin_blank => process_begin}
+    @content.each_line do |l|
+      line = l
+      line_number += 1
+      transitions[state].call
+    end # each line
+
+    @top_level
+  end
+
+  # Filter the perl markup that does the same as the rdoc
+  # filtering.  Only basic for now. Will probably need a
+  # proper parser to cope with C<<...>> etc
+  def filter(comment)
+    return '' if comment =~ /^=pod\s*$/
+    comment.gsub!(/^=pod/, '==')
+    comment.gsub!(/^=head(\d+)/) do 
+      "=" * $1.to_i
+    end
+    comment.gsub!(/=item/, '');
+    comment.gsub!(/C<(.*?)>/, '<tt>\1</tt>');
+    comment.gsub!(/I<(.*?)>/, '<i>\1</i>');
+    comment.gsub!(/B<(.*?)>/, '<b>\1</b>');
+    comment
+  end
+
+end
+