module CodeRay
module Scanners

	# YAML Scanner
	#
	# $Id$
	# 
	# See http://yaml.org for information about YAML.
	class YAML < Scanner

		include Streamable
		register_for :yaml

	private
		def setup
			@state = :initial
		end
		
		def scan_tokens tokens, options

			state = @state
			start_of_line = true
			
			until eos?
				
				kind = :error
				match = nil

				if match = scan(/\s+/m)
					if match.index ?\n  # contains newline
						start_of_line = true
					end
					kind = :space
					
				else
					
					case state
						
					when :initial
						if bol? and scan(/---(\s*.+)/m)
							kind = :preprocessor
						else
							raise_inspect '[BUG] else-case reached with state %p' % [state], tokens
						end
						
					when :attribute
						if scan(/#{TAG_END}/)
							kind = :tag
							state = :initial
						elsif scan(/#{ATTR_NAME}/o)
							kind = :attribute_name
							state = :attribute_equal
						else
							getch
						end

					else
						raise_inspect 'Unknown state: %p' % [state], tokens

					end

					start_of_line = false
				end

				match ||= matched
				if $DEBUG and (not kind or kind == :error)
					raise_inspect 'Error token %p in line %d' %
						[[match, kind], line], tokens
				end
				raise_inspect 'Empty token', tokens unless match
				
				tokens << [match, kind]
			end

			if options[:keep_state]
				@state = state
			end

			tokens
		end

	end

end
end