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from enum import Enum
from tabla import LexToken, TablaLex, tokens
from arbol import Arbol, Nodo
from shared import Control
from pprint import pprint
from errors import Error
from typing import NoReturn
from more_itertools import seekable
from nanoiter import NanoIter
from tabla import TablaLex, Token
from errors import Error
class BaseParser:
def __init__(self, iterador: NanoIter):
self.iterador: NanoIter = iterador
def want(self, *want: Token) -> (LexToken | Error):
'''Requires the next token to have a matching ltok. Returns
that token, or an error.
'''
tok: LexToken = self.lex()
if len(want) == 0:
return tok
for w in want:
if tok.tipo == w:
return tok
return Error.syntax(tok.tipo, want, tok.numlinea)
def _try(self, *want: Token) -> (LexToken | NoReturn):
'''Looks for a matching ltok from the lexer, and if not
present, unlexes the token and returns void. If found, the
token is consumed from the lexer and is returned.
'''
tok: LexToken = self.lex()
if len(want) == 0:
return tok
for w in want:
if tok.tipo == w:
return tok
self.unlex()
def peek(self, *want: Token) -> (LexToken | NoReturn):
'''Looks for a matching ltok from the lexer, unlexes the
token, and returns it; or void if it was not an ltok.
'''
tok: LexToken = self.iterador.peek()
if len(want) == 0:
return tok
for w in want:
if tok.tipo == w:
return tok
def lex(self):
return self.iterador.next()
def unlex(self):
self.iterador.back()
def synassert(self, cond: bool, msg: str) -> (Error | NoReturn):
'''Returns a syntax error if cond is false and void
otherwise.
'''
if not cond:
return Error(msg = msg)
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