djavu-asus/elpy/rpc-venv/lib/python3.11/site-packages/blib2to3/pgen2/pgen.py

   1 # Copyright 2004-2005 Elemental Security, Inc. All Rights Reserved.
   2 # Licensed to PSF under a Contributor Agreement.
   3
   4 import os
   5 from typing import (
   6     IO,
   7     Any,
   8     Dict,
   9     Iterator,
  10     List,
  11     NoReturn,
  12     Optional,
  13     Sequence,
  14     Tuple,
  15     Union,
  16 )
  17
  18 from blib2to3.pgen2 import grammar, token, tokenize
  19 from blib2to3.pgen2.tokenize import GoodTokenInfo
  20
  21 Path = Union[str, "os.PathLike[str]"]
  22
  23
  24 class PgenGrammar(grammar.Grammar):
  25     pass
  26
  27
  28 class ParserGenerator:
  29     filename: Path
  30     stream: IO[str]
  31     generator: Iterator[GoodTokenInfo]
  32     first: Dict[str, Optional[Dict[str, int]]]
  33
  34     def __init__(self, filename: Path, stream: Optional[IO[str]] = None) -> None:
  35         close_stream = None
  36         if stream is None:
  37             stream = open(filename, encoding="utf-8")
  38             close_stream = stream.close
  39         self.filename = filename
  40         self.stream = stream
  41         self.generator = tokenize.generate_tokens(stream.readline)
  42         self.gettoken()  # Initialize lookahead
  43         self.dfas, self.startsymbol = self.parse()
  44         if close_stream is not None:
  45             close_stream()
  46         self.first = {}  # map from symbol name to set of tokens
  47         self.addfirstsets()
  48
  49     def make_grammar(self) -> PgenGrammar:
  50         c = PgenGrammar()
  51         names = list(self.dfas.keys())
  52         names.sort()
  53         names.remove(self.startsymbol)
  54         names.insert(0, self.startsymbol)
  55         for name in names:
  56             i = 256 + len(c.symbol2number)
  57             c.symbol2number[name] = i
  58             c.number2symbol[i] = name
  59         for name in names:
  60             dfa = self.dfas[name]
  61             states = []
  62             for state in dfa:
  63                 arcs = []
  64                 for label, next in sorted(state.arcs.items()):
  65                     arcs.append((self.make_label(c, label), dfa.index(next)))
  66                 if state.isfinal:
  67                     arcs.append((0, dfa.index(state)))
  68                 states.append(arcs)
  69             c.states.append(states)
  70             c.dfas[c.symbol2number[name]] = (states, self.make_first(c, name))
  71         c.start = c.symbol2number[self.startsymbol]
  72         return c
  73
  74     def make_first(self, c: PgenGrammar, name: str) -> Dict[int, int]:
  75         rawfirst = self.first[name]
  76         assert rawfirst is not None
  77         first = {}
  78         for label in sorted(rawfirst):
  79             ilabel = self.make_label(c, label)
  80             ##assert ilabel not in first # XXX failed on <> ... !=
  81             first[ilabel] = 1
  82         return first
  83
  84     def make_label(self, c: PgenGrammar, label: str) -> int:
  85         # XXX Maybe this should be a method on a subclass of converter?
  86         ilabel = len(c.labels)
  87         if label[0].isalpha():
  88             # Either a symbol name or a named token
  89             if label in c.symbol2number:
  90                 # A symbol name (a non-terminal)
  91                 if label in c.symbol2label:
  92                     return c.symbol2label[label]
  93                 else:
  94                     c.labels.append((c.symbol2number[label], None))
  95                     c.symbol2label[label] = ilabel
  96                     return ilabel
  97             else:
  98                 # A named token (NAME, NUMBER, STRING)
  99                 itoken = getattr(token, label, None)
 100                 assert isinstance(itoken, int), label
 101                 assert itoken in token.tok_name, label
 102                 if itoken in c.tokens:
 103                     return c.tokens[itoken]
 104                 else:
 105                     c.labels.append((itoken, None))
 106                     c.tokens[itoken] = ilabel
 107                     return ilabel
 108         else:
 109             # Either a keyword or an operator
 110             assert label[0] in ('"', "'"), label
 111             value = eval(label)
 112             if value[0].isalpha():
 113                 if label[0] == '"':
 114                     keywords = c.soft_keywords
 115                 else:
 116                     keywords = c.keywords
 117
 118                 # A keyword
 119                 if value in keywords:
 120                     return keywords[value]
 121                 else:
 122                     c.labels.append((token.NAME, value))
 123                     keywords[value] = ilabel
 124                     return ilabel
 125             else:
 126                 # An operator (any non-numeric token)
 127                 itoken = grammar.opmap[value]  # Fails if unknown token
 128                 if itoken in c.tokens:
 129                     return c.tokens[itoken]
 130                 else:
 131                     c.labels.append((itoken, None))
 132                     c.tokens[itoken] = ilabel
 133                     return ilabel
 134
 135     def addfirstsets(self) -> None:
 136         names = list(self.dfas.keys())
 137         names.sort()
 138         for name in names:
 139             if name not in self.first:
 140                 self.calcfirst(name)
 141             # print name, self.first[name].keys()
 142
 143     def calcfirst(self, name: str) -> None:
 144         dfa = self.dfas[name]
 145         self.first[name] = None  # dummy to detect left recursion
 146         state = dfa[0]
 147         totalset: Dict[str, int] = {}
 148         overlapcheck = {}
 149         for label in state.arcs:
 150             if label in self.dfas:
 151                 if label in self.first:
 152                     fset = self.first[label]
 153                     if fset is None:
 154                         raise ValueError("recursion for rule %r" % name)
 155                 else:
 156                     self.calcfirst(label)
 157                     fset = self.first[label]
 158                     assert fset is not None
 159                 totalset.update(fset)
 160                 overlapcheck[label] = fset
 161             else:
 162                 totalset[label] = 1
 163                 overlapcheck[label] = {label: 1}
 164         inverse: Dict[str, str] = {}
 165         for label, itsfirst in overlapcheck.items():
 166             for symbol in itsfirst:
 167                 if symbol in inverse:
 168                     raise ValueError(
 169                         "rule %s is ambiguous; %s is in the first sets of %s as well"
 170                         " as %s" % (name, symbol, label, inverse[symbol])
 171                     )
 172                 inverse[symbol] = label
 173         self.first[name] = totalset
 174
 175     def parse(self) -> Tuple[Dict[str, List["DFAState"]], str]:
 176         dfas = {}
 177         startsymbol: Optional[str] = None
 178         # MSTART: (NEWLINE | RULE)* ENDMARKER
 179         while self.type != token.ENDMARKER:
 180             while self.type == token.NEWLINE:
 181                 self.gettoken()
 182             # RULE: NAME ':' RHS NEWLINE
 183             name = self.expect(token.NAME)
 184             self.expect(token.OP, ":")
 185             a, z = self.parse_rhs()
 186             self.expect(token.NEWLINE)
 187             # self.dump_nfa(name, a, z)
 188             dfa = self.make_dfa(a, z)
 189             # self.dump_dfa(name, dfa)
 190             # oldlen = len(dfa)
 191             self.simplify_dfa(dfa)
 192             # newlen = len(dfa)
 193             dfas[name] = dfa
 194             # print name, oldlen, newlen
 195             if startsymbol is None:
 196                 startsymbol = name
 197         assert startsymbol is not None
 198         return dfas, startsymbol
 199
 200     def make_dfa(self, start: "NFAState", finish: "NFAState") -> List["DFAState"]:
 201         # To turn an NFA into a DFA, we define the states of the DFA
 202         # to correspond to *sets* of states of the NFA.  Then do some
 203         # state reduction.  Let's represent sets as dicts with 1 for
 204         # values.
 205         assert isinstance(start, NFAState)
 206         assert isinstance(finish, NFAState)
 207
 208         def closure(state: NFAState) -> Dict[NFAState, int]:
 209             base: Dict[NFAState, int] = {}
 210             addclosure(state, base)
 211             return base
 212
 213         def addclosure(state: NFAState, base: Dict[NFAState, int]) -> None:
 214             assert isinstance(state, NFAState)
 215             if state in base:
 216                 return
 217             base[state] = 1
 218             for label, next in state.arcs:
 219                 if label is None:
 220                     addclosure(next, base)
 221
 222         states = [DFAState(closure(start), finish)]
 223         for state in states:  # NB states grows while we're iterating
 224             arcs: Dict[str, Dict[NFAState, int]] = {}
 225             for nfastate in state.nfaset:
 226                 for label, next in nfastate.arcs:
 227                     if label is not None:
 228                         addclosure(next, arcs.setdefault(label, {}))
 229             for label, nfaset in sorted(arcs.items()):
 230                 for st in states:
 231                     if st.nfaset == nfaset:
 232                         break
 233                 else:
 234                     st = DFAState(nfaset, finish)
 235                     states.append(st)
 236                 state.addarc(st, label)
 237         return states  # List of DFAState instances; first one is start
 238
 239     def dump_nfa(self, name: str, start: "NFAState", finish: "NFAState") -> None:
 240         print("Dump of NFA for", name)
 241         todo = [start]
 242         for i, state in enumerate(todo):
 243             print("  State", i, state is finish and "(final)" or "")
 244             for label, next in state.arcs:
 245                 if next in todo:
 246                     j = todo.index(next)
 247                 else:
 248                     j = len(todo)
 249                     todo.append(next)
 250                 if label is None:
 251                     print("    -> %d" % j)
 252                 else:
 253                     print("    %s -> %d" % (label, j))
 254
 255     def dump_dfa(self, name: str, dfa: Sequence["DFAState"]) -> None:
 256         print("Dump of DFA for", name)
 257         for i, state in enumerate(dfa):
 258             print("  State", i, state.isfinal and "(final)" or "")
 259             for label, next in sorted(state.arcs.items()):
 260                 print("    %s -> %d" % (label, dfa.index(next)))
 261
 262     def simplify_dfa(self, dfa: List["DFAState"]) -> None:
 263         # This is not theoretically optimal, but works well enough.
 264         # Algorithm: repeatedly look for two states that have the same
 265         # set of arcs (same labels pointing to the same nodes) and
 266         # unify them, until things stop changing.
 267
 268         # dfa is a list of DFAState instances
 269         changes = True
 270         while changes:
 271             changes = False
 272             for i, state_i in enumerate(dfa):
 273                 for j in range(i + 1, len(dfa)):
 274                     state_j = dfa[j]
 275                     if state_i == state_j:
 276                         # print "  unify", i, j
 277                         del dfa[j]
 278                         for state in dfa:
 279                             state.unifystate(state_j, state_i)
 280                         changes = True
 281                         break
 282
 283     def parse_rhs(self) -> Tuple["NFAState", "NFAState"]:
 284         # RHS: ALT ('|' ALT)*
 285         a, z = self.parse_alt()
 286         if self.value != "|":
 287             return a, z
 288         else:
 289             aa = NFAState()
 290             zz = NFAState()
 291             aa.addarc(a)
 292             z.addarc(zz)
 293             while self.value == "|":
 294                 self.gettoken()
 295                 a, z = self.parse_alt()
 296                 aa.addarc(a)
 297                 z.addarc(zz)
 298             return aa, zz
 299
 300     def parse_alt(self) -> Tuple["NFAState", "NFAState"]:
 301         # ALT: ITEM+
 302         a, b = self.parse_item()
 303         while self.value in ("(", "[") or self.type in (token.NAME, token.STRING):
 304             c, d = self.parse_item()
 305             b.addarc(c)
 306             b = d
 307         return a, b
 308
 309     def parse_item(self) -> Tuple["NFAState", "NFAState"]:
 310         # ITEM: '[' RHS ']' | ATOM ['+' | '*']
 311         if self.value == "[":
 312             self.gettoken()
 313             a, z = self.parse_rhs()
 314             self.expect(token.OP, "]")
 315             a.addarc(z)
 316             return a, z
 317         else:
 318             a, z = self.parse_atom()
 319             value = self.value
 320             if value not in ("+", "*"):
 321                 return a, z
 322             self.gettoken()
 323             z.addarc(a)
 324             if value == "+":
 325                 return a, z
 326             else:
 327                 return a, a
 328
 329     def parse_atom(self) -> Tuple["NFAState", "NFAState"]:
 330         # ATOM: '(' RHS ')' | NAME | STRING
 331         if self.value == "(":
 332             self.gettoken()
 333             a, z = self.parse_rhs()
 334             self.expect(token.OP, ")")
 335             return a, z
 336         elif self.type in (token.NAME, token.STRING):
 337             a = NFAState()
 338             z = NFAState()
 339             a.addarc(z, self.value)
 340             self.gettoken()
 341             return a, z
 342         else:
 343             self.raise_error(
 344                 "expected (...) or NAME or STRING, got %s/%s", self.type, self.value
 345             )
 346             raise AssertionError
 347
 348     def expect(self, type: int, value: Optional[Any] = None) -> str:
 349         if self.type != type or (value is not None and self.value != value):
 350             self.raise_error(
 351                 "expected %s/%s, got %s/%s", type, value, self.type, self.value
 352             )
 353         value = self.value
 354         self.gettoken()
 355         return value
 356
 357     def gettoken(self) -> None:
 358         tup = next(self.generator)
 359         while tup[0] in (tokenize.COMMENT, tokenize.NL):
 360             tup = next(self.generator)
 361         self.type, self.value, self.begin, self.end, self.line = tup
 362         # print token.tok_name[self.type], repr(self.value)
 363
 364     def raise_error(self, msg: str, *args: Any) -> NoReturn:
 365         if args:
 366             try:
 367                 msg = msg % args
 368             except Exception:
 369                 msg = " ".join([msg] + list(map(str, args)))
 370         raise SyntaxError(msg, (self.filename, self.end[0], self.end[1], self.line))
 371
 372
 373 class NFAState:
 374     arcs: List[Tuple[Optional[str], "NFAState"]]
 375
 376     def __init__(self) -> None:
 377         self.arcs = []  # list of (label, NFAState) pairs
 378
 379     def addarc(self, next: "NFAState", label: Optional[str] = None) -> None:
 380         assert label is None or isinstance(label, str)
 381         assert isinstance(next, NFAState)
 382         self.arcs.append((label, next))
 383
 384
 385 class DFAState:
 386     nfaset: Dict[NFAState, Any]
 387     isfinal: bool
 388     arcs: Dict[str, "DFAState"]
 389
 390     def __init__(self, nfaset: Dict[NFAState, Any], final: NFAState) -> None:
 391         assert isinstance(nfaset, dict)
 392         assert isinstance(next(iter(nfaset)), NFAState)
 393         assert isinstance(final, NFAState)
 394         self.nfaset = nfaset
 395         self.isfinal = final in nfaset
 396         self.arcs = {}  # map from label to DFAState
 397
 398     def addarc(self, next: "DFAState", label: str) -> None:
 399         assert isinstance(label, str)
 400         assert label not in self.arcs
 401         assert isinstance(next, DFAState)
 402         self.arcs[label] = next
 403
 404     def unifystate(self, old: "DFAState", new: "DFAState") -> None:
 405         for label, next in self.arcs.items():
 406             if next is old:
 407                 self.arcs[label] = new
 408
 409     def __eq__(self, other: Any) -> bool:
 410         # Equality test -- ignore the nfaset instance variable
 411         assert isinstance(other, DFAState)
 412         if self.isfinal != other.isfinal:
 413             return False
 414         # Can't just return self.arcs == other.arcs, because that
 415         # would invoke this method recursively, with cycles...
 416         if len(self.arcs) != len(other.arcs):
 417             return False
 418         for label, next in self.arcs.items():
 419             if next is not other.arcs.get(label):
 420                 return False
 421         return True
 422
 423     __hash__: Any = None  # For Py3 compatibility.
 424
 425
 426 def generate_grammar(filename: Path = "Grammar.txt") -> PgenGrammar:
 427     p = ParserGenerator(filename)
 428     return p.make_grammar()