def main():
# Display Help in the beginning of the program.
print RPN.rpn_help()
# Get into a controlled Daemon/infinite loop.
while True:
# Get the RPN expression
input_text = RPN.get_input()
# Check what have you got, if its an expression, call for evaluation
if RPN.is_expression(input_text):
output = RPN.evaluate_expression(input_text)
print output
def test_get_input_quit():
rpn.raw_input = lambda _: 'quit'
text_input = RPN.get_input()
assert text_input == 'quit'
def test_get_input_help():
rpn.raw_input = lambda _: 'help'
text_input = RPN.get_input()
assert text_input == 'help'
