MegaIng1
4 years ago
1 changed files with 6 additions and 262 deletions
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+6 -262lark/load_grammar.py
+ 6
- 262
lark/load_grammar.py
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| @@ -854,15 +854,6 @@ def _find_used_symbols(tree): | |||
| return {t for x in tree.find_data('expansion') | |||
| for t in x.scan_values(lambda t: t.type in ('RULE', 'TERMINAL'))} | |||
| def extend_expansions(tree, new): | |||
| assert isinstance(tree, Tree) and tree.data == 'expansions' | |||
| assert isinstance(new, Tree) and new.data == 'expansions' | |||
| while len(tree.children) == 2: | |||
| assert isinstance(tree.children[0], Tree) and tree.children[0].data == 'expansions', tree | |||
| tree = tree.children[0] | |||
| tree.children.insert(0, new) | |||
| def _grammar_parser(): | |||
| try: | |||
| @@ -913,256 +904,6 @@ def _parse_grammar(text, name, start='start'): | |||
| raise | |||
| class GrammarLoader: | |||
| def __init__(self, global_keep_all_tokens=False): | |||
| self.global_keep_all_tokens = global_keep_all_tokens | |||
| def import_grammar(self, grammar_path, base_path=None, import_paths=[]): | |||
| if grammar_path not in _imported_grammars: | |||
| # import_paths take priority over base_path since they should handle relative imports and ignore everything else. | |||
| to_try = import_paths + ([base_path] if base_path is not None else []) + [stdlib_loader] | |||
| for source in to_try: | |||
| try: | |||
| if callable(source): | |||
| joined_path, text = source(base_path, grammar_path) | |||
| else: | |||
| joined_path = os.path.join(source, grammar_path) | |||
| with open(joined_path, encoding='utf8') as f: | |||
| text = f.read() | |||
| except IOError: | |||
| continue | |||
| else: | |||
| grammar = self.load_grammar(text, joined_path, import_paths) | |||
| _imported_grammars[grammar_path] = grammar | |||
| break | |||
| else: | |||
| # Search failed. Make Python throw a nice error. | |||
| open(grammar_path, encoding='utf8') | |||
| assert False | |||
| return _imported_grammars[grammar_path] | |||
| def load_grammar(self, grammar_text, grammar_name='<?>', import_paths=[]): | |||
| """Parse grammar_text, verify, and create Grammar object. Display nice messages on error.""" | |||
| tree = _parse_grammar(grammar_text+'\n', grammar_name) | |||
| # tree = PrepareGrammar().transform(tree) | |||
| # Extract grammar items | |||
| defs = classify(tree.children, lambda c: c.data, lambda c: c.children) | |||
| term_defs = defs.pop('term', []) | |||
| rule_defs = defs.pop('rule', []) | |||
| statements = defs.pop('statement', []) | |||
| assert not defs | |||
| term_defs = [td if len(td)==3 else (td[0], 1, td[1]) for td in term_defs] | |||
| term_defs = [(name.value, (t, int(p))) for name, p, t in term_defs] | |||
| rule_defs = [options_from_rule(*x) for x in rule_defs] | |||
| # Execute statements | |||
| ignore, imports = [], {} | |||
| overriding_rules = [] | |||
| overriding_terms = [] | |||
| extend_rules = [] | |||
| extend_terms = [] | |||
| 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 | |||
| if isinstance(arg1, Tree): # Multi import | |||
| dotted_path = tuple(path_node.children) | |||
| names = arg1.children | |||
| aliases = dict(zip(names, names)) # Can't have aliased multi import, so all aliases will be the same as names | |||
| else: # Single import | |||
| dotted_path = tuple(path_node.children[:-1]) | |||
| name = path_node.children[-1] # Get name from dotted path | |||
| aliases = {name: arg1 or name} # Aliases if exist | |||
| if path_node.data == 'import_lib': # Import from library | |||
| base_path = None | |||
| else: # Relative import | |||
| if grammar_name == '<string>': # Import relative to script file path if grammar is coded in script | |||
| try: | |||
| base_file = os.path.abspath(sys.modules['__main__'].__file__) | |||
| except AttributeError: | |||
| base_file = None | |||
| else: | |||
| base_file = grammar_name # Import relative to grammar file path if external grammar file | |||
| if base_file: | |||
| if isinstance(base_file, PackageResource): | |||
| base_path = PackageResource(base_file.pkg_name, os.path.split(base_file.path)[0]) | |||
| else: | |||
| base_path = os.path.split(base_file)[0] | |||
| else: | |||
| base_path = os.path.abspath(os.path.curdir) | |||
| try: | |||
| import_base_path, import_aliases = imports[dotted_path] | |||
| assert base_path == import_base_path, 'Inconsistent base_path for %s.' % '.'.join(dotted_path) | |||
| import_aliases.update(aliases) | |||
| except KeyError: | |||
| imports[dotted_path] = base_path, aliases | |||
| elif stmt.data == 'declare': | |||
| for t in stmt.children: | |||
| term_defs.append([t.value, (None, None)]) | |||
| elif stmt.data == 'override': | |||
| r ,= stmt.children | |||
| if r.data == 'rule': | |||
| overriding_rules.append(options_from_rule(*r.children)) | |||
| else: | |||
| if len(r.children) == 2: | |||
| overriding_terms.append((r.children[0].value, (r.children[1], 1))) | |||
| else: | |||
| overriding_terms.append((r.children[0].value, (r.children[2], int(r.children[1])))) | |||
| elif stmt.data == 'extend': | |||
| r ,= stmt.children | |||
| if r.data == 'rule': | |||
| extend_rules.append(options_from_rule(*r.children)) | |||
| else: | |||
| if len(r.children) == 2: | |||
| extend_terms.append((r.children[0].value, (r.children[1], 1))) | |||
| else: | |||
| extend_terms.append((r.children[0].value, (r.children[2], int(r.children[1])))) | |||
| else: | |||
| assert False, stmt | |||
| # import grammars | |||
| for dotted_path, (base_path, aliases) in imports.items(): | |||
| grammar_path = os.path.join(*dotted_path) + EXT | |||
| g = self.import_grammar(grammar_path, base_path=base_path, import_paths=import_paths) | |||
| new_td, new_rd = import_from_grammar_into_namespace(g, '__'.join(dotted_path), aliases) | |||
| term_defs += new_td | |||
| rule_defs += new_rd | |||
| # replace rules by overridding rules, according to name | |||
| for r in overriding_rules: | |||
| name = r[0] | |||
| # remove overridden rule from rule_defs | |||
| overridden, rule_defs = classify_bool(rule_defs, lambda r: r[0] == name) # FIXME inefficient | |||
| if not overridden: | |||
| raise GrammarError("Cannot override a nonexisting rule: %s" % name) | |||
| rule_defs.append(r) | |||
| # Same for terminals | |||
| for t in overriding_terms: | |||
| name = t[0] | |||
| # remove overridden rule from rule_defs | |||
| overridden, term_defs = classify_bool(term_defs, lambda t: t[0] == name) # FIXME inefficient | |||
| if not overridden: | |||
| raise GrammarError("Cannot override a nonexisting terminal: %s" % name) | |||
| term_defs.append(t) | |||
| # Extend the definition of rules by adding new entries to the `expansions` node | |||
| for r in extend_rules: | |||
| name = r[0] | |||
| # remove overridden rule from rule_defs | |||
| for old in rule_defs: | |||
| if old[0] == name: | |||
| if len(old[1]) != len(r[1]): | |||
| raise GrammarError("Cannot extend templates with different parameters: %s" % name) | |||
| extend_expansions(old[2], r[2]) | |||
| break | |||
| else: | |||
| raise GrammarError("Can't extend rule %s as it wasn't defined before" % name) | |||
| # Same for terminals | |||
| for name, (e, _) in extend_terms: | |||
| for old in term_defs: | |||
| if old[0] == name: | |||
| extend_expansions(old[1][0], e) | |||
| break | |||
| else: | |||
| raise GrammarError("Can't extend terminal %s as it wasn't defined before" % name) | |||
| ## Handle terminals | |||
| # Verify correctness 1 | |||
| for name, _ in term_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 terminals (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) | |||
| term_defs.append((name, (t, 1))) | |||
| # Verify correctness 2 | |||
| terminal_names = set() | |||
| for name, _ in term_defs: | |||
| if name in terminal_names: | |||
| raise GrammarError("Terminal '%s' defined more than once" % name) | |||
| terminal_names.add(name) | |||
| if set(ignore_names) > terminal_names: | |||
| raise GrammarError("Terminals %s were marked to ignore but were not defined!" % (set(ignore_names) - terminal_names)) | |||
| resolve_term_references(term_defs) | |||
| ## Handle rules | |||
| rule_names = {} | |||
| for name, params, _x, option in rule_defs: | |||
| # We can't just simply not throw away the tokens later, we need option.keep_all_tokens to correctly generate maybe_placeholders | |||
| if self.global_keep_all_tokens: | |||
| option.keep_all_tokens = True | |||
| 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[name] = len(params) | |||
| for name, params , expansions, _o in rule_defs: | |||
| for i, p in enumerate(params): | |||
| if p in rule_names: | |||
| raise GrammarError("Template Parameter conflicts with rule %s (in template %s)" % (p, name)) | |||
| if p in params[:i]: | |||
| raise GrammarError("Duplicate Template Parameter %s (in template %s)" % (p, name)) | |||
| for temp in expansions.find_data('template_usage'): | |||
| sym = temp.children[0] | |||
| args = temp.children[1:] | |||
| if sym not in params: | |||
| if sym not in rule_names: | |||
| raise GrammarError("Template '%s' used but not defined (in rule %s)" % (sym, name)) | |||
| if len(args) != rule_names[sym]: | |||
| raise GrammarError("Wrong number of template arguments used for %s " | |||
| "(expected %s, got %s) (in rule %s)" % (sym, rule_names[sym], len(args), name)) | |||
| for sym in _find_used_symbols(expansions): | |||
| if sym.type == 'TERMINAL': | |||
| if sym not in terminal_names: | |||
| raise GrammarError("Terminal '%s' used but not defined (in rule %s)" % (sym, name)) | |||
| else: | |||
| if sym not in rule_names and sym not in params: | |||
| raise GrammarError("Rule '%s' used but not defined (in rule %s)" % (sym, name)) | |||
| return Grammar(rule_defs, term_defs, ignore_names) | |||
| class GrammarBuilder: | |||
| def __init__(self, global_keep_all_tokens=False, import_paths=None): | |||
| self.global_keep_all_tokens = global_keep_all_tokens | |||
| @@ -1216,8 +957,12 @@ class GrammarBuilder: | |||
| if tuple(params) != tuple(self._definitions[name][0]): | |||
| self._grammar_error("Cannot extend {type} with different parameters: {name}", name) | |||
| # TODO: think about what to do with 'options' | |||
| old_expansions = self._definitions[name][1] | |||
| extend_expansions(old_expansions, exp) | |||
| base = self._definitions[name][1] | |||
| while len(base.children) == 2: | |||
| assert isinstance(base.children[0], Tree) and base.children[0].data == 'expansions', tree | |||
| base = base.children[0] | |||
| base.children.insert(0, exp) | |||
| def _ignore(self, exp_or_name): | |||
| if isinstance(exp_or_name, str): | |||
| @@ -1430,4 +1175,3 @@ def load_grammar(grammar, source, import_paths, global_keep_all_tokens): | |||
| builder = GrammarBuilder(global_keep_all_tokens, import_paths) | |||
| builder.load_grammar(grammar, source) | |||
| return builder.build() | |||
| # return GrammarLoader(global_keep_all_tokens).load_grammar(grammar, source, import_paths) | |||