Mini Shell

require "rexml/child"
module REXML
	module DTD
		class EntityDecl < Child
			START = "<!ENTITY"
			START_RE = /^\s*#{START}/um
			PUBLIC = /^\s*#{START}\s+(?:%\s+)?(\w+)\s+PUBLIC\s+((["']).*?\3)\s+((["']).*?\5)\s*>/um
			SYSTEM = /^\s*#{START}\s+(?:%\s+)?(\w+)\s+SYSTEM\s+((["']).*?\3)(?:\s+NDATA\s+\w+)?\s*>/um
			PLAIN = /^\s*#{START}\s+(\w+)\s+((["']).*?\3)\s*>/um
			PERCENT = /^\s*#{START}\s+%\s+(\w+)\s+((["']).*?\3)\s*>/um
			# <!ENTITY name SYSTEM "...">
			# <!ENTITY name "...">
			def initialize src
				super()
				md = nil
				if src.match( PUBLIC )
					md = src.match( PUBLIC, true )
					@middle = "PUBLIC"
					@content = "#{md[2]} #{md[4]}"
				elsif src.match( SYSTEM )
					md = src.match( SYSTEM, true )
					@middle = "SYSTEM"
					@content = md[2]
				elsif src.match( PLAIN )
					md = src.match( PLAIN, true )
					@middle = ""
					@content = md[2]
				elsif src.match( PERCENT )
					md = src.match( PERCENT, true )
					@middle = ""
					@content = md[2]
				end
				raise ParseException.new("failed Entity match", src) if md.nil?
				@name = md[1]
			end

			def to_s
				rv = "<!ENTITY #@name "
				rv << "#@middle " if @middle.size > 0
				rv << @content
				rv
			end

			def write( output, indent )
        indent( output, indent )
				output << to_s
			end

			def EntityDecl.parse_source source, listener
				md = source.match( PATTERN_RE, true )
				thing = md[0].squeeze(" \t\n\r")
				listener.send inspect.downcase, thing 
			end
		end
	end
end