#!/usr/bin/env python
# I, Danny Milosavljevic, place this file in the public domain.

import exceptions
import sys
import codecs

class ParseError(exceptions.Exception):
	pass

class Scanner(object):
	def __init__(self, stream, position = 0):
		self.stream = codecs.getreader("UTF-8")(stream)
		self.position = position
		self.input = None

	def err(self, expected_input, got_input):
		message_text = "expected '%s', got '%s'" % (expected_input, got_input)
		raise ParseError(message_text)

	def consume(self, expected_input = None):
		old_input = self.input
		if expected_input is not None:
			if expected_input != old_input:
				self.err(expected_input, old_input)
		self.input = self.stream.read(1)
		self.position = self.position + 1
		return old_input

def whitespace_P(input):
	return input == u" "

def combining_P(input):
	if input == u"":
		return False
	ord_input = ord(input)
	return ((ord_input >= 0x0300) and (ord_input < 0x0370)) or \
	       ((ord_input >= 0x20D0) and (ord_input < 0x2100))