# Eat the next token, that should be a ')'
context.consume(expect_class=RightParen)
return expr
class RightParen(Token):
regexp = r'\)'
class Comma(Token):
regexp = r','
lexer = Lexer()
lexer.register_tokens(
Symbol, Number, String,
Addition, Substraction, Multiplication, Division,
LeftParen, RightParen, Comma)
_variable_format = re.compile('^' + variable_format + '$')
def parse_expression(expression):
equal = expression.find('=')
if equal == -1:
raise InvalidOperation("Missing target variable name",
"new_var = %s" % expression,
(0, 7))
else:
target = expression[:equal].strip()
if not _variable_format.match(target):
class ExistType(Token):
regexp = r':'
lbp = 10
def led(self, left, context):
right = context.expression(self.lbp)
if not isinstance(left, Key):
raise ParserError("Typed existence condition does not involve a "
"key")
elif not isinstance(right, Key) or right.text not in ('int', 'str'):
raise ParserError("Existence condition missing type")
return left.text, {'type': right.text}
lexer.register_tokens(Key, Number, String, Operator, ExistType)
def _update_conditions(conditions, expr):
key, cond = expr
prec = conditions.get(key)
if prec is not None:
if prec['type'] != cond['type']:
raise ParserError("Differing types for conditions on key %s: "
"%s, %s" % (key, prec['type'], cond['type']))
for k in cond.keys():
if k != 'type' and k in prec:
raise ParserError("Multiple conditions %s on key %s" %
(k, key))
prec.update(cond)
else:
class ExistType(Token):
regexp = r':'
lbp = 10
def led(self, left, context):
right = context.expression(self.lbp)
if not isinstance(left, Key):
raise ParserError("Typed existence condition does not involve a "
"key")
elif not isinstance(right, Key) or right.text not in ('int', 'str'):
raise ParserError("Existence condition missing type")
return left.text, {'type': right.text}
lexer.register_tokens(Key, Number, String, Operator, ExistType)
def _update_conditions(conditions, expr):
key, cond = expr
prec = conditions.get(key)
if prec is not None:
if prec['type'] != cond['type']:
raise ParserError("Differing types for conditions on key %s: "
"%s, %s" % (key, prec['type'], cond['type']))
for k in cond.keys():
if k != 'type' and k in prec:
raise ParserError("Multiple conditions %s on key %s" % (
k, key))
prec.update(cond)
else:
expr = context.expression()
# Eat the next token, that should be a ')'
context.consume(expect_class=RightParen)
return expr
class RightParen(Token):
regexp = r'\)'
class Comma(Token):
regexp = r','
lexer = Lexer()
lexer.register_tokens(Symbol, Number, String, Addition, Substraction,
Multiplication, Division, LeftParen, RightParen, Comma)
_variable_format = re.compile('^' + variable_format + '$')
def parse_expression(expression):
equal = expression.find('=')
if equal == -1:
raise InvalidOperation("Missing target variable name",
"new_var = %s" % expression, (0, 7))
else:
target = expression[:equal].strip()
if not _variable_format.match(target):
right = equal
if right > 0 and expression[right - 1] == ' ':
right -= 1
class LeftParen(Token):
match = RightParen
def nud(self, context):
expr = context.expression()
context.consume(expect_class=self.match)
return expr
def __repr__(self):
return '<(>'
# регистрация токенов
lexer = Lexer()
lexer.register_tokens(Integer, Addition, Multiplication, Division)
lexer.register_token(LeftParen, re.compile(r'\('))
lexer.register_token(RightParen, re.compile(r'\)'))
def parse(text):
"""Преобразует лексические токены в представление"""
return lexer.parse(text)
print("(((10+1)*(5+6/(3+1))+4*(3+1)))")
print(
f'Результат вычеслений после разбора: {parse("(((10+1)*(5+6/(3+1))+4*(3+1)))")}'
)