"""
A program for coding and decoding messages
"""
SHIFT = 1

def shift_coder(str):
	"""
	Takes a string and codes it
	"""
	characters = list(str)
	coded_characters = []
	
	for dummy_char in characters:
		ascii_int = ord(dummy_char)
		if ascii_int in range(32) + range(32, 65) + range(91, 97) + \
		range(123, 128):
			new_char = chr(ascii_int)
		elif ascii_int in range(65, 91):
			new_char = chr(((ord(dummy_char) + SHIFT - 65) % 26) + 65)
		elif ascii_int in range(97, 123):
			new_char = chr(((ord(dummy_char) + SHIFT - 97) % 26) + 97)
			
		coded_characters.append(new_char)
		
	coded_str = "".join(coded_characters)
	return coded_str

def shift_decoder(str):
	"""
	Takes a coded string and decodes it into the original message
	"""
	characters = list(str)
	coded_characters = []
	
	for dummy_char in characters:
		ascii_int = ord(dummy_char)
		
		if ascii_int in range(32) + range(32, 65) + range(91, 97) + \
		range(123, 128):
			new_char = chr(ascii_int)
		elif ascii_int in range(65, 91):
			new_char = chr(((ord(dummy_char) - SHIFT - 65) % 26) + 65)
		elif ascii_int in range(97, 123):
			new_char = chr(((ord(dummy_char) - SHIFT - 97) % 26) + 97)
			
		coded_characters.append(new_char)
		
	coded_str = "".join(coded_characters)
	return coded_str