X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/0f26a0369efc7305a1a0120355f78d85b3030e56..bb588073ab286a9f1f8d839ab2cebe13011dd22c:/src/blib2to3/pgen2/parse.py diff --git a/src/blib2to3/pgen2/parse.py b/src/blib2to3/pgen2/parse.py index 4a23d53..ad51a3d 100644 --- a/src/blib2to3/pgen2/parse.py +++ b/src/blib2to3/pgen2/parse.py @@ -9,33 +9,32 @@ See Parser/parser.c in the Python distribution for additional info on how this parsing engine works. """ -import copy from contextlib import contextmanager - -# Local imports -from . import grammar, token, tokenize from typing import ( - cast, + TYPE_CHECKING, Any, - Optional, - Text, - Union, - Tuple, + Callable, Dict, - List, Iterator, - Callable, + List, + Optional, Set, - TYPE_CHECKING, + Tuple, + Union, + cast, ) + from blib2to3.pgen2.grammar import Grammar -from blib2to3.pytree import convert, NL, Context, RawNode, Leaf, Node +from blib2to3.pytree import NL, Context, Leaf, Node, RawNode, convert + +# Local imports +from . import grammar, token, tokenize if TYPE_CHECKING: - from blib2to3.driver import TokenProxy + from blib2to3.pgen2.driver import TokenProxy -Results = Dict[Text, NL] +Results = Dict[str, NL] Convert = Callable[[Grammar, RawNode], Union[Node, Leaf]] DFA = List[List[Tuple[int, int]]] DFAS = Tuple[DFA, Dict[int, int]] @@ -54,7 +53,7 @@ def stack_copy( stack: List[Tuple[DFAS, int, RawNode]] ) -> List[Tuple[DFAS, int, RawNode]]: """Nodeless stack copy.""" - return [(copy.deepcopy(dfa), label, DUMMY_NODE) for dfa, label, _ in stack] + return [(dfa, label, DUMMY_NODE) for dfa, label, _ in stack] class Recorder: @@ -100,7 +99,7 @@ class Recorder: finally: self.parser.is_backtracking = is_backtracking - def add_token(self, tok_type: int, tok_val: Text, raw: bool = False) -> None: + def add_token(self, tok_type: int, tok_val: str, raw: bool = False) -> None: func: Callable[..., Any] if raw: func = self.parser._addtoken @@ -114,7 +113,9 @@ class Recorder: args.insert(0, ilabel) func(*args) - def determine_route(self, value: Text = None, force: bool = False) -> Optional[int]: + def determine_route( + self, value: Optional[str] = None, force: bool = False + ) -> Optional[int]: alive_ilabels = self.ilabels if len(alive_ilabels) == 0: *_, most_successful_ilabel = self._dead_ilabels @@ -131,10 +132,10 @@ class ParseError(Exception): """Exception to signal the parser is stuck.""" def __init__( - self, msg: Text, type: Optional[int], value: Optional[Text], context: Context + self, msg: str, type: Optional[int], value: Optional[str], context: Context ) -> None: Exception.__init__( - self, "%s: type=%r, value=%r, context=%r" % (msg, type, value, context) + self, f"{msg}: type={type!r}, value={value!r}, context={context!r}" ) self.msg = msg self.type = type @@ -142,7 +143,7 @@ class ParseError(Exception): self.context = context -class Parser(object): +class Parser: """Parser engine. The proper usage sequence is: @@ -210,6 +211,7 @@ class Parser(object): # See note in docstring above. TL;DR this is ignored. self.convert = convert or lam_sub self.is_backtracking = False + self.last_token: Optional[int] = None def setup(self, proxy: "TokenProxy", start: Optional[int] = None) -> None: """Prepare for parsing. @@ -235,8 +237,9 @@ class Parser(object): self.rootnode: Optional[NL] = None self.used_names: Set[str] = set() self.proxy = proxy + self.last_token = None - def addtoken(self, type: int, value: Text, context: Context) -> bool: + def addtoken(self, type: int, value: str, context: Context) -> bool: """Add a token; return True iff this is the end of the program.""" # Map from token to label ilabels = self.classify(type, value, context) @@ -284,7 +287,7 @@ class Parser(object): return self._addtoken(ilabel, type, value, context) - def _addtoken(self, ilabel: int, type: int, value: Text, context: Context) -> bool: + def _addtoken(self, ilabel: int, type: int, value: str, context: Context) -> bool: # Loop until the token is shifted; may raise exceptions while True: dfa, state, node = self.stack[-1] @@ -316,6 +319,7 @@ class Parser(object): dfa, state, node = self.stack[-1] states, first = dfa # Done with this token + self.last_token = type return False else: @@ -329,7 +333,7 @@ class Parser(object): # No success finding a transition raise ParseError("bad input", type, value, context) - def classify(self, type: int, value: Text, context: Context) -> List[int]: + def classify(self, type: int, value: str, context: Context) -> List[int]: """Turn a token into a label. (Internal) Depending on whether the value is a soft-keyword or not, @@ -342,9 +346,23 @@ class Parser(object): return [self.grammar.keywords[value]] elif value in self.grammar.soft_keywords: assert type in self.grammar.tokens + # Current soft keywords (match, case, type) can only appear at the + # beginning of a statement. So as a shortcut, don't try to treat them + # like keywords in any other context. + # ('_' is also a soft keyword in the real grammar, but for our grammar + # it's just an expression, so we don't need to treat it specially.) + if self.last_token not in ( + None, + token.INDENT, + token.DEDENT, + token.NEWLINE, + token.SEMI, + token.COLON, + ): + return [self.grammar.tokens[type]] return [ - self.grammar.soft_keywords[value], self.grammar.tokens[type], + self.grammar.soft_keywords[value], ] ilabel = self.grammar.tokens.get(type) @@ -352,7 +370,7 @@ class Parser(object): raise ParseError("bad token", type, value, context) return [ilabel] - def shift(self, type: int, value: Text, newstate: int, context: Context) -> None: + def shift(self, type: int, value: str, newstate: int, context: Context) -> None: """Shift a token. (Internal)""" if self.is_backtracking: dfa, state, _ = self.stack[-1]