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GeezerVison is showing github.com — codeql/python/extractor/lark/load_grammar.py at codeql-cli/latest · github/codeql Expand file tree/ Copy pathload_grammar.pyMore file actions 741 lines (602 loc) · 25.1 KB / Copy pathload_grammar.pyFile metadata and controls741 lines (602 loc) · 25.1 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 "Parses and creates Grammar objects" import os.path import sys from itertools import chain import re from ast import literal_eval from copy import deepcopy import pkgutil from .lexer import Token from .parse_tree_builder import ParseTreeBuilder from .parser_frontends import LALR_TraditionalLexer from .common import LexerConf, ParserConf, PatternStr, PatternRE, TokenDef from .grammar import RuleOptions, Rule, Terminal, NonTerminal, Symbol from .utils import classify, suppress from .exceptions import GrammarError, UnexpectedCharacters, UnexpectedToken from .tree import Tree, SlottedTree as ST from .visitors import Transformer, Visitor, v_args, Transformer_InPlace inline_args = v_args(inline=True) __path__ = os.path.dirname(__file__) GRAMMAR_PACKAGES = ['lark.grammars'] EXT = '.lark' _RE_FLAGS = 'imslux' def is_terminal(sym): return sym.isupper() _TERMINAL_NAMES = { '.' : 'DOT', ',' : 'COMMA', ':' : 'COLON', ';' : 'SEMICOLON', '+' : 'PLUS', '-' : 'MINUS', '*' : 'STAR', '/' : 'SLASH', '\\' : 'BACKSLASH', '|' : 'VBAR', '?' : 'QMARK', '!' : 'BANG', '@' : 'AT', '#' : 'HASH', '$' : 'DOLLAR', '%' : 'PERCENT', '^' : 'CIRCUMFLEX', '&' : 'AMPERSAND', '_' : 'UNDERSCORE', '<' : 'LESSTHAN', '>' : 'MORETHAN', '=' : 'EQUAL', '"' : 'DBLQUOTE', '\'' : 'QUOTE', '`' : 'BACKQUOTE', '~' : 'TILDE', '(' : 'LPAR', ')' : 'RPAR', '{' : 'LBRACE', '}' : 'RBRACE', '[' : 'LSQB', ']' : 'RSQB', '\n' : 'NEWLINE', '\r\n' : 'CRLF', '\t' : 'TAB', ' ' : 'SPACE', } # Grammar Parser TERMINALS = { '_LPAR': r'\(', '_RPAR': r'\)', '_LBRA': r'\[', '_RBRA': r'\]', 'OP': '[+*][?]?|[?](?![a-z])', '_COLON': ':', '_COMMA': ',', '_OR': r'\|', '_DOT': r'\.', 'TILDE': '~', 'RULE': '!?[_?]?[a-z][_a-z0-9]*', 'TERMINAL': '_?[A-Z][_A-Z0-9]*', 'STRING': r'"(\\"|\\\\|[^"\n])*?"i?', 'REGEXP': r'/(?!/)(\\/|\\\\|[^/\n])*?/[%s]*' % _RE_FLAGS, '_NL': r'(\r?\n)+\s*', 'WS': r'[ \t]+', 'COMMENT': r'//[^\n]*', '_TO': '->', '_IGNORE': r'%ignore', '_DECLARE': r'%declare', '_IMPORT': r'%import', 'NUMBER': r'\d+', } RULES = { 'start': ['_list'], '_list': ['_item', '_list _item'], '_item': ['rule', 'token', 'statement', '_NL'], 'rule': ['RULE _COLON expansions _NL', 'RULE _DOT NUMBER _COLON expansions _NL'], 'expansions': ['alias', 'expansions _OR alias', 'expansions _NL _OR alias'], '?alias': ['expansion _TO RULE', 'expansion'], 'expansion': ['_expansion'], '_expansion': ['', '_expansion expr'], '?expr': ['atom', 'atom OP', 'atom TILDE NUMBER', 'atom TILDE NUMBER _DOT _DOT NUMBER', ], '?atom': ['_LPAR expansions _RPAR', 'maybe', 'value'], 'value': ['terminal', 'nonterminal', 'literal', 'range'], 'terminal': ['TERMINAL'], 'nonterminal': ['RULE'], '?name': ['RULE', 'TERMINAL'], 'maybe': ['_LBRA expansions _RBRA'], 'range': ['STRING _DOT _DOT STRING'], 'token': ['TERMINAL _COLON expansions _NL', 'TERMINAL _DOT NUMBER _COLON expansions _NL'], 'statement': ['ignore', 'import', 'declare'], 'ignore': ['_IGNORE expansions _NL'], 'declare': ['_DECLARE _declare_args _NL'], 'import': ['_IMPORT _import_path _NL', '_IMPORT _import_path _LPAR name_list _RPAR _NL', '_IMPORT _import_path _TO TERMINAL _NL'], '_import_path': ['import_lib', 'import_rel'], 'import_lib': ['_import_args'], 'import_rel': ['_DOT _import_args'], '_import_args': ['name', '_import_args _DOT name'], 'name_list': ['_name_list'], '_name_list': ['name', '_name_list _COMMA name'], '_declare_args': ['name', '_declare_args name'], 'literal': ['REGEXP', 'STRING'], } @inline_args class EBNF_to_BNF(Transformer_InPlace): def __init__(self): self.new_rules = [] self.rules_by_expr = {} self.prefix = 'anon' self.i = 0 self.rule_options = None def _add_recurse_rule(self, type_, expr): if expr in self.rules_by_expr: return self.rules_by_expr[expr] new_name = '__%s_%s_%d' % (self.prefix, type_, self.i) self.i += 1 t = NonTerminal(Token('RULE', new_name, -1)) tree = ST('expansions', [ST('expansion', [expr]), ST('expansion', [t, expr])]) self.new_rules.append((new_name, tree, self.rule_options)) self.rules_by_expr[expr] = t return t def expr(self, rule, op, *args): if op.value == '?': return ST('expansions', [rule, ST('expansion', [])]) elif op.value == '+': # a : b c+ d # --> # a : b _c d # _c : _c c | c; return self._add_recurse_rule('plus', rule) elif op.value == '*': # a : b c* d # --> # a : b _c? d # _c : _c c | c; new_name = self._add_recurse_rule('star', rule) return ST('expansions', [new_name, ST('expansion', [])]) elif op.value == '~': if len(args) == 1: mn = mx = int(args[0]) else: mn, mx = map(int, args) if mx < mn: raise GrammarError("Bad Range for %s (%d..%d isn't allowed)" % (rule, mn, mx)) return ST('expansions', [ST('expansion', [rule] * n) for n in range(mn, mx+1)]) assert False, op class SimplifyRule_Visitor(Visitor): @staticmethod def _flatten(tree): while True: to_expand = [i for i, child in enumerate(tree.children) if isinstance(child, Tree) and child.data == tree.data] if not to_expand: break tree.expand_kids_by_index(*to_expand) def expansion(self, tree): # rules_list unpacking # a : b (c|d) e # --> # a : b c e | b d e # # In AST terms: # expansion(b, expansions(c, d), e) # --> # expansions( expansion(b, c, e), expansion(b, d, e) ) self._flatten(tree) for i, child in enumerate(tree.children): if isinstance(child, Tree) and child.data == 'expansions': tree.data = 'expansions' tree.children = [self.visit(ST('expansion', [option if i==j else other for j, other in enumerate(tree.children)])) for option in set(child.children)] self._flatten(tree) break def alias(self, tree): rule, alias_name = tree.children if rule.data == 'expansions': aliases = [] for child in tree.children[0].children: aliases.append(ST('alias', [child, alias_name])) tree.data = 'expansions' tree.children = aliases def expansions(self, tree): self._flatten(tree) tree.children = list(set(tree.children)) class RuleTreeToText(Transformer): def expansions(self, x): return x def expansion(self, symbols): return symbols, None def alias(self, x): (expansion, _alias), alias = x assert _alias is None, (alias, expansion, '-', _alias) # Double alias not allowed return expansion, alias.value @inline_args class CanonizeTree(Transformer_InPlace): def maybe(self, expr): return ST('expr', [expr, Token('OP', '?', -1)]) def tokenmods(self, *args): if len(args) == 1: return list(args) tokenmods, value = args return tokenmods + [value] class PrepareAnonTerminals(Transformer_InPlace): "Create a unique list of anonymous tokens. Attempt to give meaningful names to them when we add them" def __init__(self, tokens): self.tokens = tokens self.token_set = {td.name for td in self.tokens} self.token_reverse = {td.pattern: td for td in tokens} self.i = 0 @inline_args def pattern(self, p): value = p.value if p in self.token_reverse and p.flags != self.token_reverse[p].pattern.flags: raise GrammarError(u'Conflicting flags for the same terminal: %s' % p) token_name = None if isinstance(p, PatternStr): try: # If already defined, use the user-defined token name token_name = self.token_reverse[p].name except KeyError: # Try to assign an indicative anon-token name try: token_name = _TERMINAL_NAMES[value] except KeyError: if value.isalnum() and value[0].isalpha() and value.upper() not in self.token_set: with suppress(UnicodeEncodeError): value.upper().encode('ascii') # Make sure we don't have unicode in our token names token_name = value.upper() elif isinstance(p, PatternRE): if p in self.token_reverse: # Kind of a wierd placement.name token_name = self.token_reverse[p].name else: assert False, p if token_name is None: token_name = '__ANON_%d' % self.i self.i += 1 if token_name not in self.token_set: assert p not in self.token_reverse self.token_set.add(token_name) tokendef = TokenDef(token_name, p) self.token_reverse[p] = tokendef self.tokens.append(tokendef) return Terminal(token_name, filter_out=isinstance(p, PatternStr)) def _rfind(s, choices): return max(s.rfind(c) for c in choices) def _fix_escaping(s): w = '' i = iter(s) for n in i: w += n if n == '\\': n2 = next(i) if n2 == '\\': w += '\\\\' elif n2 not in 'unftr': w += '\\' w += n2 w = w.replace('\\"', '"').replace("'", "\\'") to_eval = "u'''%s'''" % w try: s = literal_eval(to_eval) except SyntaxError as e: raise ValueError(s, e) return s def _literal_to_pattern(literal): v = literal.value flag_start = _rfind(v, '/"')+1 assert flag_start > 0 flags = v[flag_start:] assert all(f in _RE_FLAGS for f in flags), flags v = v[:flag_start] assert v[0] == v[-1] and v[0] in '"/' x = v[1:-1] s = _fix_escaping(x) if literal.type == 'STRING': s = s.replace('\\\\', '\\') return { 'STRING': PatternStr, 'REGEXP': PatternRE }[literal.type](s, flags) @inline_args class PrepareLiterals(Transformer_InPlace): def literal(self, literal): return ST('pattern', [_literal_to_pattern(literal)]) def range(self, start, end): assert start.type == end.type == 'STRING' start = start.value[1:-1] end = end.value[1:-1] assert len(start) == len(end) == 1, (start, end, len(start), len(end)) regexp = '[%s-%s]' % (start, end) return ST('pattern', [PatternRE(regexp)]) class TokenTreeToPattern(Transformer): def pattern(self, ps): p ,= ps return p def expansion(self, items): assert items if len(items) == 1: return items[0] if len({i.flags for i in items}) > 1: raise GrammarError("Lark doesn't support joining tokens with conflicting flags!") return PatternRE(''.join(i.to_regexp() for i in items), items[0].flags if items else ()) def expansions(self, exps): if len(exps) == 1: return exps[0] if len({i.flags for i in exps}) > 1: raise GrammarError("Lark doesn't support joining tokens with conflicting flags!") return PatternRE('(?:%s)' % ('|'.join(i.to_regexp() for i in exps)), exps[0].flags) def expr(self, args): inner, op = args[:2] if op == '~': if len(args) == 3: op = "{%d}" % int(args[2]) else: mn, mx = map(int, args[2:]) if mx < mn: raise GrammarError("Bad Range for %s (%d..%d isn't allowed)" % (inner, mn, mx)) op = "{%d,%d}" % (mn, mx) else: assert len(args) == 2 return PatternRE('(?:%s)%s' % (inner.to_regexp(), op), inner.flags) def alias(self, t): raise GrammarError("Aliasing not allowed in terminals (You used -> in the wrong place)") def value(self, v): return v[0] class PrepareSymbols(Transformer_InPlace): def value(self, v): v ,= v if isinstance(v, Tree): return v elif v.type == 'RULE': return NonTerminal(v.value) elif v.type == 'TERMINAL': return Terminal(v.value, filter_out=v.startswith('_')) assert False def _choice_of_rules(rules): return ST('expansions', [ST('expansion', [Token('RULE', name)]) for name in rules]) class Grammar: def __init__(self, rule_defs, token_defs, ignore): self.token_defs = token_defs self.rule_defs = rule_defs self.ignore = ignore def compile(self): # We change the trees in-place (to support huge grammars) # So deepcopy allows calling compile more than once. token_defs = deepcopy(list(self.token_defs)) rule_defs = deepcopy(self.rule_defs) # ================= # Compile Tokens # ================= # Convert token-trees to strings/regexps transformer = PrepareLiterals() * TokenTreeToPattern() for name, (token_tree, priority) in token_defs: if token_tree is None: # Terminal added through %declare continue expansions = list(token_tree.find_data('expansion')) if len(expansions) == 1 and not expansions[0].children: raise GrammarError("Terminals cannot be empty (%s)" % name) tokens = [TokenDef(name, transformer.transform(token_tree), priority) for name, (token_tree, priority) in token_defs if token_tree] # ================= # Compile Rules # ================= # 1. Pre-process terminals transformer = PrepareLiterals() * PrepareSymbols() * PrepareAnonTerminals(tokens) # Adds to tokens # 2. Convert EBNF to BNF (and apply step 1) ebnf_to_bnf = EBNF_to_BNF() rules = [] for name, rule_tree, options in rule_defs: ebnf_to_bnf.rule_options = RuleOptions(keep_all_tokens=True) if options and options.keep_all_tokens else None tree = transformer.transform(rule_tree) rules.append((name, ebnf_to_bnf.transform(tree), options)) rules += ebnf_to_bnf.new_rules assert len(rules) == len({name for name, _t, _o in rules}), "Whoops, name collision" # 3. Compile tree to Rule objects rule_tree_to_text = RuleTreeToText() simplify_rule = SimplifyRule_Visitor() compiled_rules = [] for name, tree, options in rules: simplify_rule.visit(tree) expansions = rule_tree_to_text.transform(tree) for expansion, alias in expansions: if alias and name.startswith('_'): raise GrammarError("Rule %s is marked for expansion (it starts with an underscore) and isn't allowed to have aliases (alias=%s)" % (name, alias)) assert all(isinstance(x, Symbol) for x in expansion), expansion rule = Rule(NonTerminal(name), expansion, alias, options) compiled_rules.append(rule) return tokens, compiled_rules, self.ignore _imported_grammars = {} def import_grammar(grammar_path): if grammar_path not in _imported_grammars: for package in GRAMMAR_PACKAGES: text = pkgutil.get_data(package, grammar_path).decode("utf-8") grammar = load_grammar(text, grammar_path) _imported_grammars[grammar_path] = grammar return _imported_grammars[grammar_path] def resolve_token_references(token_defs): # TODO Cycles detection # TODO Solve with transitive closure (maybe) token_dict = {k:t for k, (t,_p) in token_defs} assert len(token_dict) == len(token_defs), "Same name defined twice?" while True: changed = False for name, (token_tree, _p) in token_defs: if token_tree is None: # Terminal added through %declare continue for exp in token_tree.find_data('value'): item ,= exp.children if isinstance(item, Token): if item.type == 'RULE': raise GrammarError("Rules aren't allowed inside terminals (%s in %s)" % (item, name)) if item.type == 'TERMINAL': exp.children[0] = token_dict[item] changed = True if not changed: break def options_from_rule(name, *x): if len(x) > 1: priority, expansions = x priority = int(priority) else: expansions ,= x priority = None keep_all_tokens = name.startswith('!') name = name.lstrip('!') expand1 = name.startswith('?') name = name.lstrip('?') return name, expansions, RuleOptions(keep_all_tokens, expand1, priority=priority) def symbols_from_strcase(expansion): return [Terminal(x, filter_out=x.startswith('_')) if is_terminal(x) else NonTerminal(x) for x in expansion] @inline_args class PrepareGrammar(Transformer_InPlace): def terminal(self, name): return name def nonterminal(self, name): return name class GrammarLoader: def __init__(self): tokens = [TokenDef(name, PatternRE(value)) for name, value in TERMINALS.items()] rules = [options_from_rule(name, x) for name, x in RULES.items()] rules = [Rule(NonTerminal(r), symbols_from_strcase(x.split()), None, o) for r, xs, o in rules for x in xs] callback = ParseTreeBuilder(rules, ST).create_callback() lexer_conf = LexerConf(tokens, ['WS', 'COMMENT']) parser_conf = ParserConf(rules, callback, 'start') self.parser = LALR_TraditionalLexer(lexer_conf, parser_conf) self.canonize_tree = CanonizeTree() def load_grammar(self, grammar_text, grammar_name='<?>'): "Parse grammar_text, verify, and create Grammar object. Display nice messages on error." try: tree = self.canonize_tree.transform( self.parser.parse(grammar_text+'\n') ) except UnexpectedCharacters as e: context = e.get_context(grammar_text) raise GrammarError("Unexpected input at line %d column %d in %s: \n\n%s" % (e.line, e.column, grammar_name, context)) except UnexpectedToken as e: context = e.get_context(grammar_text) error = e.match_examples(self.parser.parse, { 'Unclosed parenthesis': ['a: (\n'], 'Umatched closing parenthesis': ['a: )\n', 'a: [)\n', 'a: (]\n'], 'Expecting rule or token definition (missing colon)': ['a\n', 'a->\n', 'A->\n', 'a A\n'], 'Alias expects lowercase name': ['a: -> "a"\n'], 'Unexpected colon': ['a::\n', 'a: b:\n', 'a: B:\n', 'a: "a":\n'], 'Misplaced operator': ['a: b??', 'a: b(?)', 'a:+\n', 'a:?\n', 'a:*\n', 'a:|*\n'], 'Expecting option ("|") or a new rule or token definition': ['a:a\n()\n'], '%import expects a name': ['%import "a"\n'], '%ignore expects a value': ['%ignore %import\n'], }) if error: raise GrammarError("%s at line %s column %s\n\n%s" % (error, e.line, e.column, context)) elif 'STRING' in e.expected: raise GrammarError("Expecting a value at line %s column %s\n\n%s" % (e.line, e.column, context)) raise tree = PrepareGrammar().transform(tree) # Extract grammar items defs = classify(tree.children, lambda c: c.data, lambda c: c.children) token_defs = defs.pop('token', []) rule_defs = defs.pop('rule', []) statements = defs.pop('statement', []) assert not defs token_defs = [td if len(td)==3 else (td[0], 1, td[1]) for td in token_defs] token_defs = [(name.value, (t, int(p))) for name, p, t in token_defs] # Execute statements ignore = [] declared = [] for (stmt,) in statements: if stmt.data == 'ignore': t ,= stmt.children ignore.append(t) elif stmt.data == 'import': if len(stmt.children) > 1: path_node, arg1 = stmt.children else: path_node ,= stmt.children arg1 = None dotted_path = path_node.children if isinstance(arg1, Tree): # Multi import names = arg1.children aliases = names # Can't have aliased multi import, so all aliases will be the same as names else: # Single import names = [dotted_path[-1]] # Get name from dotted path aliases = [arg1] if arg1 else names # Aliases if exist dotted_path = dotted_path[:-1] grammar_path = os.path.join(*dotted_path) + EXT if path_node.data == 'import_lib': # Import from library g = import_grammar(grammar_path) else: # Relative import if grammar_name == '<string>': # Import relative to script file path if grammar is coded in script base_file = os.path.abspath(sys.modules['__main__'].__file__) else: base_file = grammar_name # Import relative to grammar file path if external grammar file base_path = os.path.split(base_file)[0] g = import_grammar(grammar_path, base_paths=[base_path]) for name, alias in zip(names, aliases): token_options = dict(g.token_defs)[name] assert isinstance(token_options, tuple) and len(token_options)==2 token_defs.append([alias.value, token_options]) elif stmt.data == 'declare': for t in stmt.children: token_defs.append([t.value, (None, None)]) else: assert False, stmt # Verify correctness 1 for name, _ in token_defs: if name.startswith('__'): raise GrammarError('Names starting with double-underscore are reserved (Error at %s)' % name) # Handle ignore tokens # XXX A slightly hacky solution. Recognition of %ignore TERMINAL as separate comes from the lexer's # inability to handle duplicate tokens (two names, one value) ignore_names = [] for t in ignore: if t.data=='expansions' and len(t.children) == 1: t2 ,= t.children if t2.data=='expansion' and len(t2.children) == 1: item ,= t2.children if item.data == 'value': item ,= item.children if isinstance(item, Token) and item.type == 'TERMINAL': ignore_names.append(item.value) continue name = '__IGNORE_%d'% len(ignore_names) ignore_names.append(name) token_defs.append((name, (t, 0))) # Verify correctness 2 token_names = set() for name, _ in token_defs: if name in token_names: raise GrammarError("Token '%s' defined more than once" % name) token_names.add(name) if set(ignore_names) > token_names: raise GrammarError("Tokens %s were marked to ignore but were not defined!" % (set(ignore_names) - token_names)) # Resolve token references resolve_token_references(token_defs) rules = [options_from_rule(*x) for x in rule_defs] rule_names = set() for name, _x, _o in rules: if name.startswith('__'): raise GrammarError('Names starting with double-underscore are reserved (Error at %s)' % name) if name in rule_names: raise GrammarError("Rule '%s' defined more than once" % name) rule_names.add(name) for name, expansions, _o in rules: used_symbols = {t for x in expansions.find_data('expansion') for t in x.scan_values(lambda t: t.type in ('RULE', 'TERMINAL'))} for sym in used_symbols: if is_terminal(sym): if sym not in token_names: raise GrammarError("Token '%s' used but not defined (in rule %s)" % (sym, name)) else: if sym not in rule_names: raise GrammarError("Rule '%s' used but not defined (in rule %s)" % (sym, name)) # TODO don't include unused tokens, they can only cause trouble! return Grammar(rules, token_defs, ignore_names) load_grammar = GrammarLoader().load_grammar |
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