def __init__(self, initial_entry):
self.preanalysis = ''
self.parser = Parser(initial_entry)
def test_decimal(self):
parser = Parser('222.98')
self.assertEqual(parser.next_token(), '222.98', 'Testing decimal.')
class Analyzer(object):
def __init__(self, initial_entry):
self.preanalysis = ''
self.parser = Parser(initial_entry)
def next_token(self):
"""Gets the next token and calculates preanalysis."""
token = self.parser.next_token()
if token == None:
self.preanalysis = '$'
else:
self.preanalysis = token
def analyze(self):
self.next_token()
result = self.start()
if self.preanalysis != '$':
raise Exception('Found ' + self.preanalysis + ', expecting ' + '""')
return result
def start(self):
return self.expression(0)
def expression(self, amount):
if self.preanalysis == '$':
raise Exception('Found $, expecting token')
result_term = self.term(amount)
result_eq = self.expression_quote(result_term)
return result_eq
def expression_quote(self, left):
if self.preanalysis == '+':
self.operator()
right = self.term(left)
return self.expression_quote(left + right)
elif self.preanalysis == '-':
self.operator()
right = self.term(left)
return self.expression_quote(left - right)
else:
return left
def term(self, amount):
if self.preanalysis == '$':
raise Exception('Found $, expecting token')
result_factor = self.factor(amount)
result_tq = self.term_quote(result_factor)
return result_tq
def term_quote(self, left):
if self.preanalysis == '*':
self.operator()
right = self.factor(left)
return self.term_quote(left * right)
elif self.preanalysis == '/':
self.operator()
right = self.factor(left)
return self.term_quote(left / right)
else:
return left
def factor(self, amount):
if self.preanalysis == '$':
raise Exception('Found $, expecting token')
result_primary = self.primary(amount)
result_fq = self.factor_quote(result_primary)
return result_fq
def factor_quote(self, left):
if self.preanalysis == '^':
self.operator()
right = self.primary(left)
return self.factor_quote(left ** right)
else:
return left
def primary(self, amount):
if self.preanalysis == '$':
raise Exception('Found $, expecting token')
elif self.preanalysis == '(':
# TODO: open parenthesis
self.operator()
result = self.expression(amount) # TODO
# TODO: close parenthesis
self.operator()
return result
else:
try:
float(self.preanalysis)
except ValueError:
raise Exception('Found ' + self.preanalysis + 'expecting "(" or number')
return self.number()
def number(self):
if self.preanalysis == '$':
raise Exception('Found $, expecting token')
try:
if '.' in self.preanalysis:
result = float(self.preanalysis)
else:
result = int(self.preanalysis)
except ValueError:
raise Exception('Found ' + self.preanalysis + 'expecting number')
self.next_token()
return result
def operator(self):
if self.preanalysis == '$':
raise Exception('Found $, expecting token')
self.next_token()
def test_integer(self):
parser = Parser('222')
self.assertEqual(parser.next_token(), '222', 'Testing integer.')
