Fixed infinite recursion when parsing complex BNF node

This commit is contained in:
2020-06-23 15:22:27 +02:00
parent 912455c343
commit 7310bc5522
28 changed files with 1082 additions and 276 deletions
+42 -52
View File
@@ -1,6 +1,7 @@
from collections import namedtuple
from dataclasses import dataclass
from enum import Enum
from typing import Set
import core.utils
from core.builtin_concepts import BuiltinConcepts
@@ -12,6 +13,11 @@ from parsers.BaseParser import Node, BaseParser, ErrorNode
DEBUG_COMPILED = True
@dataclass
class ChickenAndEggError(Exception):
concepts: Set[str]
@dataclass()
class LexerNode(Node):
start: int # starting index in the tokens list
@@ -422,7 +428,7 @@ class CN(HelperWithPos):
ConceptNode tester class
It matches with ConceptNode but with less constraints
CNC == ConceptNode if concept key, start, end and source are the same
CN == ConceptNode if concept key, start, end and source are the same
"""
def __init__(self, concept, start=None, end=None, source=None):
@@ -496,6 +502,9 @@ class CNC(CN):
super().__init__(concept_key, start, end, source)
self.compiled = kwargs
self.exclude_body = exclude_body
if "body" in self.compiled:
self.compiled[ConceptParts.BODY] = self.compiled["body"]
del self.compiled["body"]
def __eq__(self, other):
if id(self) == id(other):
@@ -516,7 +525,10 @@ class CNC(CN):
to_compare = {k: v for k, v in other.concept.compiled.items() if k != ConceptParts.BODY}
else:
to_compare = other.concept.compiled
return self.compiled == to_compare
if self.compiled == to_compare:
return True
else:
return False
if not isinstance(other, CNC):
return False
@@ -613,7 +625,7 @@ class BaseNodeParser(BaseParser):
:param concepts
:return:
"""
concepts_by_first_keyword = self.get_concepts_by_first_keyword(context, concepts).body
concepts_by_first_keyword = self.get_concepts_by_first_token(context, concepts).body
self.concepts_by_first_keyword = self.resolve_concepts_by_first_keyword(context, concepts_by_first_keyword).body
def reset_parser(self, context, parser_input: ParserInput):
@@ -626,38 +638,6 @@ class BaseNodeParser(BaseParser):
self.add_error(self.sheerka.new(BuiltinConcepts.ERROR, body=e), False)
return False
return True
# self.text = text
#
# try:
# self.tokens = list(self.get_input_as_tokens(text))
#
#
# self.token = None
# self.pos = -1
# return True
# def add_error(self, error, next_token=True):
# self.error_sink.append(error)
# if next_token:
# self.parser_input.next_token()
# return error
# def get_token(self) -> Token:
# return self.token
#
# def next_token(self, skip_whitespace=True):
# if self.token and self.token.type == TokenKind.EOF:
# return False
#
# self.pos += 1
# self.token = self.tokens[self.pos]
#
# if skip_whitespace:
# while self.token.type == TokenKind.WHITESPACE or self.token.type == TokenKind.NEWLINE:
# self.pos += 1
# self.token = self.tokens[self.pos]
#
# return self.token.type != TokenKind.EOF
def get_concepts(self, token, to_keep, custom=None, to_map=None, strip_quotes=False):
"""
@@ -698,7 +678,7 @@ class BaseNodeParser(BaseParser):
return custom_concepts if custom else None
@staticmethod
def get_concepts_by_first_keyword(context, concepts, use_sheerka=False):
def get_concepts_by_first_token(context, concepts, use_sheerka=False):
"""
Create the map describing the first token expected by a concept
:param context:
@@ -718,22 +698,26 @@ class BaseNodeParser(BaseParser):
for keyword in keywords:
res.setdefault(keyword, []).append(concept.id)
# 'uniquify' the lists
for k, v in res.items():
res[k] = core.utils.make_unique(v)
return sheerka.ret("BaseNodeParser", True, res)
@staticmethod
def resolve_concepts_by_first_keyword(context, concepts_by_first_keyword):
sheerka = context.sheerka
def _make_unique(elements):
keys = {}
for e in elements:
keys[e] = 1
return list(keys.keys())
def _resolve_concepts(concept_str):
resolved = []
to_resolve = []
def resolve_concepts(concept_str):
resolved = set()
to_resolve = set()
concept = sheerka.get_by_id(core.utils.unstr_concept(concept_str)[1])
if concept.id in already_seen:
raise ChickenAndEggError(already_seen)
else:
already_seen.add(concept.id)
if sheerka.isaset(context, concept):
concepts = sheerka.get_set_elements(context, concept)
else:
@@ -743,25 +727,31 @@ class BaseNodeParser(BaseParser):
BaseNodeParser.ensure_bnf(context, concept) # need to make sure that it cannot fail
keywords = BaseNodeParser.get_first_tokens(sheerka, concept)
for keyword in keywords:
(to_resolve if keyword.startswith("c:|") else resolved).append(keyword)
(to_resolve if keyword.startswith("c:|") else resolved).add(keyword)
for concept_to_resolve_str in to_resolve:
resolved += _resolve_concepts(concept_to_resolve_str)
resolved |= resolve_concepts(concept_to_resolve_str)
return resolved
res = {}
for k, v in concepts_by_first_keyword.items():
if k.startswith("c:|"):
resolved_keywords = _resolve_concepts(k)
for resolved in resolved_keywords:
res.setdefault(resolved, []).extend(v)
try:
already_seen = set()
resolved_keywords = resolve_concepts(k)
for resolved in resolved_keywords:
res.setdefault(resolved, []).extend(v)
except ChickenAndEggError as ex:
context.log(f"Chicken and egg detected for {k}, concepts={ex.concepts}")
# res[k] = sheerka.new(BuiltinConcepts.CHICKEN_AND_EGG,
# body=[sheerka.get_by_id(c) for c in ex.concepts])
else:
res.setdefault(k, []).extend(v)
# 'uniquify' the lists
for k, v in res.items():
res[k] = _make_unique(v)
res[k] = core.utils.make_unique(v)
return sheerka.ret("BaseNodeParser", True, res)
@@ -797,7 +787,7 @@ class BaseNodeParser(BaseParser):
if concept.metadata.definition_type == DEFINITION_TYPE_BNF and not concept.bnf:
from parsers.BnfParser import BnfParser
regex_parser = BnfParser()
desc = f"Resolving BNF {concept.metadata.definition}"
desc = f"Resolving BNF '{concept.metadata.definition}'"
with context.push(BuiltinConcepts.INIT_BNF,
concept,
who=parser_name,
+256 -91
View File
@@ -154,18 +154,6 @@ class ConceptExpression(ParsingExpression):
[node])
# class ConceptGroupExpression(ConceptExpression):
# def _parse(self, parser_helper):
# node = self.nodes[0].parse(parser_helper)
# if node is None:
# return None
# return NonTerminalNode(self,
# node.start,
# node.end,
# node.tokens, # node is an OrderedChoice
# [node])
class Sequence(ParsingExpression):
"""
Will match sequence of parser expressions in exact order they are defined.
@@ -422,6 +410,69 @@ class StrMatch(Match):
return None
# class RegExMatch(Match):
# '''
# This Match class will perform input matching based on Regular Expressions.
#
# Args:
# to_match (regex string): A regular expression string to match.
# It will be used to create regular expression using re.compile.
# ignore_case(bool): If case insensitive match is needed.
# Default is None to support propagation from global parser setting.
# multiline(bool): allow regex to works on multiple lines
# (re.DOTALL flag). Default is None to support propagation from
# global parser setting.
# str_repr(str): A string that is used to represent this regex.
# re_flags: flags parameter for re.compile if neither ignore_case
# or multiple are set.
#
# '''
# def __init__(self, to_match, rule_name='', root=False, ignore_case=None,
# multiline=None, str_repr=None, re_flags=re.MULTILINE):
# super(RegExMatch, self).__init__(rule_name, root)
# self.to_match_regex = to_match
# self.ignore_case = ignore_case
# self.multiline = multiline
# self.explicit_flags = re_flags
#
# self.to_match = str_repr if str_repr is not None else to_match
#
# def compile(self):
# flags = self.explicit_flags
# if self.multiline is True:
# flags |= re.DOTALL
# if self.multiline is False and flags & re.DOTALL:
# flags -= re.DOTALL
# if self.ignore_case is True:
# flags |= re.IGNORECASE
# if self.ignore_case is False and flags & re.IGNORECASE:
# flags -= re.IGNORECASE
# self.regex = re.compile(self.to_match_regex, flags)
#
# def __str__(self):
# return self.to_match
#
# def __unicode__(self):
# return self.__str__()
#
# def _parse(self, parser):
# c_pos = parser.position
# m = self.regex.match(parser.input, c_pos)
# if m:
# matched = m.group()
# if parser.debug:
# parser.dprint(
# "++ Match '%s' at %d => '%s'" %
# (matched, c_pos, parser.context(len(matched))))
# parser.position += len(matched)
# if matched:
# return Terminal(self, c_pos, matched, extra_info=m)
# else:
# if parser.debug:
# parser.dprint("-- NoMatch at {}".format(c_pos))
# parser._nm_raise(self, c_pos, parser)
class ParsingExpressionVisitor:
"""
visit ParsingExpression
@@ -550,7 +601,7 @@ class BnfConceptParserHelper:
forked.eat_concept(concept, token)
# init
parsing_expression = self.parser.get_parsing_expression(concept)
parsing_expression = self.parser.get_parsing_expression(self.parser.context, concept)
if not isinstance(parsing_expression, ParsingExpression):
self.debug.append(concept)
error_msg = f"Failed to parse concept '{concept}'"
@@ -733,6 +784,11 @@ class BnfConceptParserHelper:
return concept
@dataclass
class UnderConstruction:
concept_id: str
class BnfNodeParser(BaseNodeParser):
def __init__(self, **kwargs):
super().__init__("BnfNode", 50, **kwargs)
@@ -769,6 +825,11 @@ class BnfNodeParser(BaseNodeParser):
return valid_parser_helpers
def get_concepts_sequences(self):
"""
Main method that parses the tokens and extract the concepts
:return:
"""
def _add_forked_to_concept_parser_helpers():
# check that if some new InfixToPostfix are created
for parser in concept_parser_helpers:
@@ -836,110 +897,214 @@ class BnfNodeParser(BaseNodeParser):
return concept_parser_helpers
def get_parsing_expression(self, concept, already_seen=None):
def check_for_infinite_recursion(self, parsing_expression, already_found, only_first=False):
if isinstance(parsing_expression, ConceptExpression):
if parsing_expression.concept in already_found:
return True
already_found.add(parsing_expression.concept)
return self.check_for_infinite_recursion(parsing_expression.nodes[0], already_found, False)
if isinstance(parsing_expression, Sequence):
# for sequence, we need to check all nodes
if only_first:
nodes = [] if len(parsing_expression.nodes) == 0 else [parsing_expression.nodes[0]]
else:
nodes = parsing_expression.nodes
for node in nodes:
already_found_for_current_node = already_found.copy()
if self.check_for_infinite_recursion(node, already_found_for_current_node, False):
already_found.update(already_found_for_current_node)
return True
return False
if isinstance(parsing_expression, OrderedChoice):
# for ordered choice, if there is at least one node that does not resolved to a recursion
# we are safe
for node in parsing_expression.nodes:
already_found_for_current_node = already_found.copy()
if self.check_for_infinite_recursion(node, already_found, True):
already_found.update(already_found_for_current_node)
return True
else:
return False
return False
return False
def get_parsing_expression(self, context, concept):
if concept.id in self.concepts_grammars:
return self.concepts_grammars.get(concept.id)
if not concept.bnf:
BaseNodeParser.ensure_bnf(self.context, concept, self.name)
grammar = self.concepts_grammars.copy()
to_resolve = {} # the key is the instance id of the parsing expression
isa_concepts = set()
self.resolve_concept_parsing_expression(context, concept, grammar, to_resolve, isa_concepts)
expression = concept.bnf
desc = f"Resolving parsing expression {expression}"
with self.context.push(BuiltinConcepts.INIT_BNF, concept, who=self.name, obj=concept, desc=desc) as sub_context:
sub_context.add_inputs(expression=expression)
resolved = self.resolve_parsing_expression(expression, already_seen or set())
sub_context.add_values(return_values=resolved)
for _id, pe in to_resolve.items():
for i, node in enumerate(pe.nodes):
if isinstance(node, UnderConstruction):
pe.nodes[i] = grammar.get(node.concept_id)
self.concepts_grammars.put(concept.id, resolved)
concepts_in_recursion = set()
if self.check_for_infinite_recursion(pe, concepts_in_recursion):
cycle = context.sheerka.new(BuiltinConcepts.CHICKEN_AND_EGG, body={c.id for c in concepts_in_recursion})
for concept in concepts_in_recursion:
grammar[concept.id] = cycle
if self.has_error:
return None
# Make sure you do not put isa concepts in cache
# why :
# twenties = 'twenty' number where number < 10
# hundreds = number 'hundred' where number < 99
# the concept of number depends on its utilisation
for concept_id in [c for c in grammar if c not in isa_concepts]:
self.concepts_grammars.put(concept_id, grammar[concept_id])
return self.concepts_grammars.get(concept.id)
def resolve_parsing_expression(self, parsing_expression, already_seen):
def resolve_concept_parsing_expression(self, context, concept, grammar, to_resolve, isa_concepts):
if concept.id in grammar:
return grammar.get(concept.id)
def inner_resolve(expression, inner_already_seen):
# if isinstance(expression, Concept):
# if self.sheerka.isaset(self.context, expression):
# ret = ConceptGroupExpression(expression, rule_name=expression.name)
# else:
# ret = ConceptExpression(expression, rule_name=expression.name)
# possible_recursion.add(expression)
if isinstance(expression, str):
ret = StrMatch(expression, ignore_case=self.ignore_case)
desc = f"Get parsing expression for '{concept}'"
with context.push(BuiltinConcepts.INIT_BNF, concept, who=self.name, obj=concept, desc=desc) as sub_context:
if not concept.bnf: # to save a function call. Not sure it worth it.
BaseNodeParser.ensure_bnf(sub_context, concept, self.name)
elif not isinstance(expression, ParsingExpression):
return expression # escalate the error
grammar[concept.id] = UnderConstruction(concept.id)
sheerka = context.sheerka
elif isinstance(expression, ConceptExpression):
concept = self.get_concept(expression.concept)
if concept in inner_already_seen:
return self.sheerka.new(BuiltinConcepts.CHICKEN_AND_EGG, body=concept)
expression.concept = concept
inner_already_seen.add(concept)
if concept.metadata.definition_type == DEFINITION_TYPE_BNF:
expression = concept.bnf
desc = f"Bnf concept detected. Resolving parsing expression '{expression}'"
with sub_context.push(BuiltinConcepts.INIT_BNF, concept, who=self.name, obj=concept, desc=desc) as ssc:
ssc.add_inputs(expression=expression)
resolved = self.resolve_parsing_expression(ssc, expression, grammar, to_resolve, isa_concepts)
ssc.add_values(return_values=resolved)
if not self.sheerka.is_known(concept):
unknown_concept = self.sheerka.new(BuiltinConcepts.UNKNOWN_CONCEPT, body=concept)
return self.add_error(unknown_concept)
elif sheerka.isaset(context, concept):
desc = f"Concept is a group. Resolving parsing expression using 'isa'"
with sub_context.push(BuiltinConcepts.INIT_BNF, concept, who=self.name, obj=concept, desc=desc) as ssc:
ssc.add_inputs(concept=concept)
isa_concepts.add(concept.id)
concepts_in_group = self.sheerka.get_set_elements(ssc, concept)
# bnf concept
elif concept.metadata.definition_type == DEFINITION_TYPE_BNF:
pe = self.get_parsing_expression(concept, inner_already_seen)
# concepts_in_group comes from a set, so the order of its elements is not guaranteed
# to avoid random failure (ie random CHICKEN_AND_EGG), we need to rearrange
# We also remove the root concept (the one from get_parsing_expression())
elif self.sheerka.isaset(self.context, concept):
concepts_in_group = self.sheerka.get_set_elements(self.context, concept)
nodes = [ConceptExpression(c, rule_name=c.name) for c in concepts_in_group]
pe = inner_resolve(OrderedChoice(*nodes), inner_already_seen)
root_concept_as_set = set(context.search(
predicate=lambda ec: ec.action == BuiltinConcepts.INIT_BNF,
get_obj=lambda ec: ec.obj,
stop=lambda ec: ec.action != BuiltinConcepts.INIT_BNF)) # there only one item in the set
root_concept = list(root_concept_as_set)[0]
reordered = []
for c in concepts_in_group:
if c.id == root_concept.id:
continue
else:
# regular concepts
tokens = Tokenizer(concept.name)
nodes = [StrMatch(token.strip_quote) for token in list(tokens)[:-1]]
pe = inner_resolve(nodes[0] if len(nodes) == 1 else Sequence(nodes), inner_already_seen)
# I do not guaranty the same order every time, but I minimize the ChickenAndEgg random issue
if c.metadata.definition_type == DEFINITION_TYPE_BNF or sheerka.isaset(ssc, c):
reordered.append(c)
else:
reordered.insert(0, c)
if not isinstance(pe, ParsingExpression):
return pe
expression.nodes = [pe]
expression.rule_name = expression.rule_name or concept.name
ret = expression
elif isinstance(expression, StrMatch):
ret = expression
if ret.ignore_case is None:
ret.ignore_case = self.ignore_case
elif isinstance(expression, Sequence) or \
isinstance(expression, OrderedChoice) or \
isinstance(expression, ZeroOrMore) or \
isinstance(expression, OneOrMore) or \
isinstance(expression, Optional):
ret = expression
ret.nodes = []
for e in ret.elements:
pe = inner_resolve(e, already_seen.copy())
if not isinstance(pe, ParsingExpression):
return pe
ret.nodes.append(pe)
nodes = [ConceptExpression(c, rule_name=c.name) for c in reordered]
resolved = self.resolve_parsing_expression(ssc,
OrderedChoice(*nodes),
grammar,
to_resolve,
isa_concepts)
ssc.add_values(concepts_in_group=concepts_in_group)
ssc.add_values(return_values=resolved)
else:
ret = self.add_error(GrammarErrorNode(f"Unrecognized grammar element '{expression}'."), False)
desc = f"Concept is a simple concept."
with sub_context.push(BuiltinConcepts.INIT_BNF, concept, who=self.name, obj=concept, desc=desc) as ssc:
tokens = Tokenizer(concept.name, yield_eof=False)
nodes = [StrMatch(token.strip_quote) for token in tokens]
expression = nodes[0] if len(nodes) == 1 else Sequence(nodes)
resolved = self.resolve_parsing_expression(ssc, expression, grammar, to_resolve, isa_concepts)
# Translate separator expression.
if isinstance(expression, Repetition) and expression.sep:
expression.sep = inner_resolve(expression.sep, already_seen)
grammar[concept.id] = resolved
return ret
if self.has_error:
sub_context.add_values(errors=self.error_sink)
return None
parsing_expression = inner_resolve(parsing_expression, already_seen)
return parsing_expression
sub_context.add_values(return_values=resolved)
return resolved
def get_concept(self, concept):
def resolve_parsing_expression(self, context, expression, grammar, to_resolve, isa_concepts):
if isinstance(expression, str):
ret = StrMatch(expression, ignore_case=self.ignore_case)
elif not isinstance(expression, ParsingExpression):
return expression # escalate the error
elif isinstance(expression, ConceptExpression):
concept = self.get_concept(context, expression.concept)
expression.concept = concept
if not self.sheerka.is_known(concept):
unknown_concept = self.sheerka.new(BuiltinConcepts.UNKNOWN_CONCEPT, body=concept)
return self.add_error(unknown_concept)
pe = self.resolve_concept_parsing_expression(context, concept, grammar, to_resolve, isa_concepts)
if not isinstance(pe, (ParsingExpression, UnderConstruction)):
return pe # an error is detected, escalate it
#
# if isinstance(pe, UnderConstruction) and expression.concept.id == pe.concept_id:
# return pe # we are looking for ourself, just return it
if isinstance(pe, UnderConstruction):
to_resolve[id(expression)] = expression
expression.nodes = [pe]
expression.rule_name = expression.rule_name or concept.name
ret = expression
elif isinstance(expression, StrMatch):
ret = expression
if ret.ignore_case is None:
ret.ignore_case = self.ignore_case
elif isinstance(expression, Sequence) or \
isinstance(expression, OrderedChoice) or \
isinstance(expression, ZeroOrMore) or \
isinstance(expression, OneOrMore) or \
isinstance(expression, Optional):
ret = expression
ret.nodes = []
for e in ret.elements:
pe = self.resolve_parsing_expression(context, e, grammar, to_resolve, isa_concepts)
if not isinstance(pe, (ParsingExpression, UnderConstruction)):
return pe # an error is detected, escalate it
if isinstance(pe, UnderConstruction):
to_resolve[id(ret)] = ret # remember that there is an unresolved parsing expression
ret.nodes.append(pe)
else:
ret = self.add_error(GrammarErrorNode(f"Unrecognized grammar element '{expression}'."), False)
# Translate separator expression.
if isinstance(ret, Repetition) and expression.sep:
expression.sep = self.resolve_parsing_expression(context,
expression.sep,
grammar,
to_resolve,
isa_concepts)
return ret
def get_concept(self, context, concept):
if isinstance(concept, Concept):
return concept
if concept in self.context.concepts:
return self.context.concepts[concept]
if concept in context.concepts:
return context.concepts[concept]
return self.sheerka.get_by_key(concept)
def parse(self, context, parser_input: ParserInput):