what.py3

from modgrammar import *
from functools import *
from math import *

#grammar_whitespace_mode = 'optional'

NAMESPACE = {}

class NonZeroDigit(Grammar):
	grammar = WORD("1-9")

class Digit(Grammar):
	grammar = WORD("0-9")

class Integer(Grammar):
	grammar = (NonZeroDigit, ZERO_OR_MORE(Digit))
	def grammar_elem_init(self, sd):
		self.value = int(self.string)

class FloatingPoint(Grammar):
	grammar = OR((Integer, '.', ZERO_OR_MORE(Digit)) , ('.', ONE_OR_MORE(Digit)))
	def grammar_elem_init(self, sd):
		self.value = float(self.string)

class Initial(Grammar):
	grammar = WORD('a-z') | WORD('A-Z') | '_'

class Medial(Grammar):
	grammar = Initial | Digit

class Var(Grammar):
	grammar = (Initial, ZERO_OR_MORE(Medial))
	def grammar_elem_init(self, sd):
		self.value = NAMESPACE[self.string]

class Val(Grammar):
	grammar = Integer | FloatingPoint | Var | ('(',REF("Expression"),')') | REF("Function")
	def grammar_elem_init(self, sd):
		for i in self:
			if i:
				self.value = i.value
				break

class ValT(Grammar):
	grammar = Val | REF("TrigE")
	def grammar_elem_init(self, sd):
		for i in self:
			if i:
				self.value = i.value
				break

class ExpS(Grammar):
	grammar = '^'

class ExpT(Grammar):
	grammar = ValT | (ValT, ExpS, REF("NegT"))
	def grammar_elem_init(self, sd):
		if self[0]:
			self.value = self[0].value
		else:
			self.value = self[1][0].value ** self[1][2].value

class ExpE(Grammar):
	grammar = ValT | (Val, ExpS, REF("NegE"))
	def grammar_elem_init(self, sd):
		if self[0]:
			self.value = self[0].value
		else:
			self.value = self[1][0].value ** self[1][2].value

class NegS(Grammar):
	grammar = '_'

class NegT(Grammar):
	grammar = ExpT | (NegS, REF("NegT"))
	def grammar_elem_init(self, sd):
		if self[0]:
			self.value = self[0].value
		else:
			self.value = -self[1][0].value

class NegE(Grammar):
	grammar = ExpE | (NegS, REF("RegE"))
	def grammar_elem_init(self, sd):
		if self[0]:
			self.value = self[0].value
		else:
			self.value = -self[1][0].value

class MulS(Grammar):
	grammar = L('*') | '/'

class MulT(Grammar):
	grammar = NegT | (REF("MulT"), MulS, NegT)
	def grammar_elem_init(self, sd):
		if self[0]:
			self.value = self[0].value
		elif self[1][2].string == '*':
			self.value = self[1][0].value * self[1][2].value
		elif self[1][2].string == '/':
			self.value = self[1][0].value / self[1][2].value

class MulE(Grammar):
	grammar = NegE | (REF("MulE"), MulS, NegE)
	def grammar_elem_init(self, sd):
		if self[0]:
			self.value = self[0].value
		elif self[1][2].string == '*':
			self.value = self[1][0].value * self[1][2].value
		elif self[1][2].string == '/':
			self.value = self[1][0].value / self[1][2].value
class TrigS(Grammar):
	grammar = L('sin') | 'cos' | 'tan' | 'asin' | 'acos' | 'atan'

class TrigE(Grammar):
	grammar = (TrigS, ' ', MulE | REF("TrigE"))
	def grammar_elem_init(self, sd):
		if self[2][0]:
			self.value = eval(self[0][0].string)(self[2][0].value)
		else:
			self.value = eval(self[0][0].string)(self[2][1].value)

class AddS(Grammar):
	grammar = L('+') | '-'

class AddE(Grammar):
	grammar = MulT | (REF("AddE"), AddS, MulE)
	def grammar_elem_init(self, sd):
		if self[0]:
			self.value = self[0].value
		elif self[1][2].string == '+':
			self.value = self[1][0].value + self[1][2].value
		elif self[1][2].string == '-':
			self.value = self[1][0].value - self[1][2].value

class Function(Grammar):
	grammar = (Var, '(', REF("Expression"), ZERO_OR_MORE((',',REF("Expression"))), ')')
	def grammar_elem_init(self, sd):
		res = [self[2].value]
		for i in range(len(self[3])):
			if i % 2 == 1:
				res.append(self[3][i].value)
		self.value = NAMESPACE[self[0]](*res)

class Expression(Grammar):
	grammar = AddE
	def grammar_elem_init(self, sd):
		self.value = self[0].value

p = Expression.parser()
print(p.parse_string("0"))