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#!/bin/env python
# -*- coding: utf-8 -*-
# Copyright (C) 2022 Iván Alejandro Ávalos Díaz <avalos@disroot.org>
# Edgar Alexis López Martínez <edgarmlmp@gmail.com>
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
from typing import List, cast, Optional
from more_itertools import peekable
from tabla import Token, LexToken
from parse.base import BaseParser
from errors import Error
from parse.type import ParseType
from parse.ident import ParseIdent
from parse.expr import ParseExpr, Expr
from astree.decl import DeclGlobal, DeclFunc, Decl
class ParseDecl:
def __init__(self, parser: BaseParser):
self.parser = parser
def decl_global(self) -> (DeclGlobal | Error):
# Tipo
_type = ParseType(self.parser)._type()
if type(_type) is Error:
return _type
# Identificador
ident = ParseIdent(self.parser).ident()
if type(ident) is Error:
return ident
# =
init: Optional[Expr] = None
eq = self.parser._try(Token.EQUAL)
if eq:
# Expresión
init = ParseExpr(self.parser).expr()
if type(init) is Error:
return init
return DeclGlobal(ident = ident,
_type = _type,
init = init)
def decl_func(self) -> (DeclFunc | Error):
# funcion
tok = self.parser.want(Token.FUNCTION)
if type(tok) is Error:
return tok
# Tipo
_type = ParseType(self.parser)._type()
if type(_type) is Error:
return _type
# Identificador
ident = ParseIdent(self.parser).ident()
if type(ident) is Error:
return ident
# Prototipo
proto = ParseType(self.parser).prototype(_type)
if type(proto) is Error:
return proto
init = ParseExpr(self.parser).compound_expr()
if type(init) is Error:
return init
return DeclFunc(ident = ident,
prototype = proto,
body = init)
# Parses a declaration.
def decl(self) -> (Decl | Error):
toks = [Token.BOOLEAN, Token.CHAR, Token.INT, Token.STRING, Token.VOID, Token.FUNCTION]
_next = self.parser.want(*toks)
decl: Optional[Decl] = None
if type(_next) is Error:
return _next
elif _next.tipo is Token.FUNCTION:
self.parser.unlex()
decl = self.decl_func()
else:
self.parser.unlex()
decl = self.decl_global()
if type(decl) is Error:
return decl
# ;
semicolon = self.parser.want(Token.SEMICOLON)
if type(semicolon) is Error:
return semicolon
return decl
# Parses the declarations for a sub-parser.
def decls(self) -> (List[Decl] | Error):
decls: List[Decl] = []
while not self.parser.peek(Token.EOF):
decl = self.decl()
if type(decl) is Error:
return decl
decls.append(decl)
return decls
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