797 lines
25 KiB
Python
797 lines
25 KiB
Python
#####################################################################################################
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# This implementation of the parser is highly inspired by the arpeggio project (https://github.com/textX/Arpeggio)
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# I don't directly use the project, but it helped me figure out
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# what to do.
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# Dejanović I., Milosavljević G., Vaderna R.:
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# Arpeggio: A flexible PEG parser for Python,
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# Knowledge-Based Systems, 2016, 95, 71 - 74, doi:10.1016/j.knosys.2015.12.004
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#####################################################################################################
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from dataclasses import field, dataclass
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from collections import defaultdict
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from core.builtin_concepts import BuiltinConcepts
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from core.concept import Concept
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from core.tokenizer import TokenKind, Tokenizer, Token
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from parsers.BaseParser import BaseParser, Node, ErrorNode
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import core.utils
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import logging
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log = logging.getLogger(__name__)
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def flatten(iterable):
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if iterable is None:
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return []
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result = []
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for e in iterable:
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if e.parsing_expression.rule_name is not None and e.parsing_expression.rule_name != "":
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if hasattr(e, "children"):
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e.children = flatten(e.children)
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result.append(e)
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elif hasattr(e, "children"):
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result.extend(flatten(e.children))
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else:
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result.append(e)
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return result
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@dataclass()
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class LexerNode(Node):
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start: int
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end: int
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tokens: list = None
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source: str = None
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def __post_init__(self):
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if self.source is None:
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self.source = BaseParser.get_text_from_tokens(self.tokens)
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def __eq__(self, other):
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if not isinstance(other, LexerNode):
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return False
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return self.start == other.start and self.end == other.end
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class ConceptNode(LexerNode):
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"""
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Returned by the ConceptLexerParser
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It represents a recognized concept
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"""
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def __init__(self, concept, start, end, tokens=None, source=None, underlying=None):
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super().__init__(start, end, tokens, source)
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self.concept = concept
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self.underlying = underlying
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if self.source is None:
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self.source = BaseParser.get_text_from_tokens(self.tokens)
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def __eq__(self, other):
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if isinstance(other, tuple):
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if len(other) == 2:
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return self.concept == other[0] and self.source == other[1]
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else:
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return self.concept == other[0] and \
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self.start == other[1] and \
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self.end == other[2] and \
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self.source == other[3]
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if not super().__eq__(other):
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return False
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if not isinstance(other, ConceptNode):
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return False
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return self.concept == other.concept and \
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self.source == other.source and \
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self.underlying == other.underlying
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def __hash__(self):
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return hash((self.concept, self.start, self.end, self.source, self.underlying))
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def __repr__(self):
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return f"ConceptNode(concept='{self.concept}', start={self.start}, end={self.end}, source='{self.source}')"
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class NonTerminalNode(LexerNode):
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"""
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Returned by the ConceptLexerParser
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"""
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def __init__(self, parsing_expression, start, end, tokens, children=None):
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super().__init__(start, end, tokens)
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self.parsing_expression = parsing_expression
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self.children = children
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def __repr__(self):
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name = self.parsing_expression.rule_name or self.parsing_expression.__class__.__name__
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if len(self.children) > 0:
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sub_names = "(" + ",".join([repr(child) for child in self.children]) + ")"
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else:
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sub_names = ""
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return name + sub_names
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def __eq__(self, other):
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if not super().__eq__(other):
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return False
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if not isinstance(other, NonTerminalNode):
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return False
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return self.parsing_expression == other.parsing_expression and \
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self.start == other.start and \
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self.end == other.end and \
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self.children == other.children
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def __hash__(self):
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return hash((self.parsing_expression, self.start, self.end, self.children))
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class TerminalNode(LexerNode):
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"""
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Returned by the ConceptLexerParser
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"""
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def __init__(self, parsing_expression, start, end, value):
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super().__init__(start, end, source=value)
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self.parsing_expression = parsing_expression
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self.value = value
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def __repr__(self):
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name = self.parsing_expression.rule_name or ""
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return name + f"'{self.value}'"
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def __eq__(self, other):
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if not super().__eq__(other):
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return False
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if not isinstance(other, TerminalNode):
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return False
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return self.parsing_expression == other.parsing_expression and \
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self.start == other.start and \
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self.end == other.end and \
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self.value == other.value
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def __hash__(self):
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return hash((self.parsing_expression, self.start, self.end, self.value))
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@dataclass()
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class GrammarErrorNode(ErrorNode):
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message: str
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@dataclass()
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class UnknownConceptNode(ErrorNode):
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concept_key: str
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@dataclass()
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class TooManyConceptNode(ErrorNode):
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concept_key: str
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class ParsingExpression:
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def __init__(self, *args, **kwargs):
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self.elements = args
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nodes = kwargs.get('nodes', [])
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if not hasattr(nodes, '__iter__'):
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nodes = [nodes]
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self.nodes = nodes
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self.rule_name = kwargs.get('rule_name', '')
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def __eq__(self, other):
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if not isinstance(other, ParsingExpression):
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return False
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return self.rule_name == other.rule_name and self.elements == other.elements
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def __hash__(self):
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return hash((self.rule_name, self.elements))
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def parse(self, parser):
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return self._parse(parser)
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class Sequence(ParsingExpression):
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"""
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Will match sequence of parser expressions in exact order they are defined.
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"""
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def _parse(self, parser):
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init_pos = parser.pos
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end_pos = parser.pos
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children = []
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for e in self.nodes:
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node = e.parse(parser)
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if node is None:
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return None
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else:
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if node.end != -1: # because returns -1 when no match
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children.append(node)
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end_pos = node.end
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return NonTerminalNode(self, init_pos, end_pos, parser.tokens[init_pos: end_pos + 1], children)
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def __repr__(self):
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to_str = ", ".join(repr(n) for n in self.elements)
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return f"({to_str})"
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class OrderedChoice(ParsingExpression):
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"""
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Will match one among multiple
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It will stop at the first match (so the order of definition is important)
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"""
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def _parse(self, parser):
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init_pos = parser.pos
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for e in self.nodes:
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node = e.parse(parser)
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if node:
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return NonTerminalNode(self, init_pos, node.end, parser.tokens[init_pos: node.end + 1], [node])
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parser.seek(init_pos) # backtrack
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return None
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def __repr__(self):
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to_str = "| ".join(repr(n) for n in self.elements)
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return f"({to_str})"
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class Optional(ParsingExpression):
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"""
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Will match or not the elements
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if many matches, will choose longest one
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If you need order, use Optional(OrderedChoice)
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"""
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def _parse(self, parser):
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init_pos = parser.pos
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selected_node = NonTerminalNode(self, parser.pos, -1, [], []) # means that nothing is found
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for e in self.nodes:
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node = e.parse(parser)
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if node:
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if node.end > selected_node.end:
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selected_node = NonTerminalNode(
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self,
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node.start,
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node.end,
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parser.tokens[node.start: node.end + 1],
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[node])
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parser.seek(init_pos) # backtrack
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if selected_node.end != -1:
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parser.seek(selected_node.end)
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parser.next_token() # eat the tokens found
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return selected_node
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def __repr__(self):
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if len(self.elements) == 1:
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return f"{self.elements[0]}?"
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else:
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to_str = ", ".join(repr(n) for n in self.elements)
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return f"({to_str})?"
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class Repetition(ParsingExpression):
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"""
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Base class for all repetition-like parser expressions (?,*,+)
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Args:
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eolterm(bool): Flag that indicates that end of line should
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terminate repetition match.
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"""
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def __init__(self, *elements, **kwargs):
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super(Repetition, self).__init__(*elements, **kwargs)
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self.sep = kwargs.get('sep', None)
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class ZeroOrMore(Repetition):
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"""
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ZeroOrMore will try to match parser expression specified zero or more
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times. It will never fail.
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"""
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def _parse(self, parser):
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init_pos = parser.pos
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end_pos = -1
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children = []
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while True:
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current_pos = parser.pos
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# maybe eat the separator if needed
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if self.sep and children:
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sep_result = self.sep.parse(parser)
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if sep_result is None:
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parser.seek(current_pos)
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break
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# eat the ZeroOrMore
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node = self.nodes[0].parse(parser)
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if node is None:
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parser.seek(current_pos)
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break
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else:
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if node.end != -1: # because returns -1 when no match
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children.append(node)
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end_pos = node.end
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if len(children) == 0:
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return NonTerminalNode(self, init_pos, -1, [], [])
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return NonTerminalNode(self, init_pos, end_pos, parser.tokens[init_pos: end_pos + 1], children)
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def __repr__(self):
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to_str = ", ".join(repr(n) for n in self.elements)
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return f"({to_str})*"
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class OneOrMore(Repetition):
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"""
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OneOrMore will try to match parser expression specified one or more times.
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"""
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def _parse(self, parser):
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init_pos = parser.pos
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end_pos = -1
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children = []
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while True:
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current_pos = parser.pos
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# maybe eat the separator if needed
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if self.sep and children:
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sep_result = self.sep.parse(parser)
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if sep_result is None:
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parser.seek(current_pos)
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break
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# eat the ZeroOrMore
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node = self.nodes[0].parse(parser)
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if node is None:
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parser.seek(current_pos)
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break
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else:
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if node.end != -1: # because returns -1 when no match
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children.append(node)
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end_pos = node.end
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if len(children) == 0: # if nothing is found, it's an error
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return None
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return NonTerminalNode(self, init_pos, end_pos, parser.tokens[init_pos: end_pos + 1], children)
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def __repr__(self):
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to_str = ", ".join(repr(n) for n in self.elements)
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return f"({to_str})+"
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class UnorderedGroup(Repetition):
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"""
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Will try to match all of the parsing expression in any order.
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"""
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def _parse(self, parser):
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raise NotImplementedError()
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# def __repr__(self):
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# to_str = ", ".join(repr(n) for n in self.elements)
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# return f"({to_str})#"
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class Match(ParsingExpression):
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"""
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Base class for all classes that will try to match something from the input.
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"""
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def __init__(self, rule_name, root=False):
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super(Match, self).__init__(rule_name=rule_name, root=root)
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def parse(self, parser):
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result = self._parse(parser)
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return result
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class StrMatch(Match):
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"""
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Matches a literal
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"""
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def __init__(self, to_match, rule_name="", root=False, ignore_case=True):
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super(Match, self).__init__(rule_name=rule_name, root=root)
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self.to_match = to_match
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self.ignore_case = ignore_case
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def __repr__(self):
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return f"'{self.to_match}'"
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def __eq__(self, other):
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if not super().__eq__(other):
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return False
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if not isinstance(other, StrMatch):
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return False
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return self.to_match == other.to_match and self.ignore_case == other.ignore_case
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def _parse(self, parser):
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token = parser.get_token()
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m = str(token.value).lower() == self.to_match.lower() if self.ignore_case \
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else token.value == self.to_match
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if m:
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node = TerminalNode(self, parser.pos, parser.pos, token.value)
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parser.next_token()
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return node
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return None
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class ConceptMatch(Match):
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"""
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Will match a concept
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It used only for rule definition
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When the grammar is created, it is replaced by the actual concept
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"""
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def __init__(self, concept, rule_name=""):
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super(Match, self).__init__(rule_name=rule_name)
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self.concept = concept
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def __repr__(self):
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return f"{self.concept}"
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def __eq__(self, other):
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if not super().__eq__(other):
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return False
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if not isinstance(other, ConceptMatch):
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return False
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if isinstance(self.concept, Concept):
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return self.concept.name == other.concept.name
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return self.concept == other.concept
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def _parse(self, parser):
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to_match = parser.get_concept(self.concept) if isinstance(self.concept, str) else self.concept
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if parser.sheerka.isinstance(to_match, BuiltinConcepts.UNKNOWN_CONCEPT):
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return None
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if to_match not in parser.concepts_grammars:
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return None
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self.concept = to_match # Memoize
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node = parser.concepts_grammars[to_match].parse(parser)
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if node is None:
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return None
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return NonTerminalNode(self, node.start, node.end, parser.tokens[node.start: node.end + 1], [node])
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class ConceptLexerParser(BaseParser):
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def __init__(self, **kwargs):
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super().__init__("ConceptLexer")
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if 'grammars' in kwargs:
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self.concepts_grammars = kwargs.get("grammars")
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elif 'sheerka' in kwargs:
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self.concepts_grammars = kwargs.get("sheerka").concepts_grammars
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else:
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self.concepts_grammars = {}
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self.ignore_case = True
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self.token = None
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self.pos = -1
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self.tokens = None
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self.context = None
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self.text = None
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self.sheerka = None
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def add_error(self, error, next_token=True):
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self.has_error = True
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self.error_sink.append(error)
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if next_token:
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self.next_token()
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return error
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def reset_parser(self, context, text):
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self.context = context
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self.sheerka = context.sheerka
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self.text = text
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if isinstance(text, str):
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self.tokens = list(Tokenizer(text))
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else:
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self.tokens = list(text)
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self.tokens.append(Token(TokenKind.EOF, "", -1, -1, -1)) # make sure to finish with end of file token
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self.token = None
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self.pos = -1
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self.next_token()
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def get_token(self) -> Token:
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return self.token
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def next_token(self, skip_whitespace=True):
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if self.token and self.token.type == TokenKind.EOF:
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return False
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self.pos += 1
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self.token = self.tokens[self.pos]
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if skip_whitespace:
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while self.token.type == TokenKind.WHITESPACE or self.token.type == TokenKind.NEWLINE:
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self.pos += 1
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self.token = self.tokens[self.pos]
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return self.token.type != TokenKind.EOF
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def seek(self, pos):
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self.pos = pos
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self.token = self.tokens[self.pos]
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return True
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def rewind(self, offset, skip_whitespace=True):
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self.pos += offset
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self.token = self.tokens[self.pos]
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if skip_whitespace:
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while self.pos > 0 and (self.token.type == TokenKind.WHITESPACE or self.token.type == TokenKind.NEWLINE):
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self.pos -= 1
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self.token = self.tokens[self.pos]
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def initialize(self, context, concepts_definitions):
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"""
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Adds a bunch of concepts, and how they can be recognized
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:param context: execution context
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:param concepts_definitions: dictionary of concept, concept_definition
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:return:
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"""
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self.context = context
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self.sheerka = context.sheerka
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concepts_to_resolve = set()
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# ## Gets the grammars
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for concept, concept_def in concepts_definitions.items():
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concept.init_key() # make sure that the key is initialized
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grammar = self.get_model(concept_def, concepts_to_resolve)
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self.concepts_grammars[concept] = grammar
|
|
|
|
if self.has_error:
|
|
return self.sheerka.ret(self.name, False, self.error_sink)
|
|
|
|
# ## Removes concepts with infinite recursions
|
|
concepts_to_remove = self.detect_infinite_recursion(concepts_to_resolve)
|
|
for concept in concepts_to_remove:
|
|
concepts_to_resolve.remove(concept)
|
|
del self.concepts_grammars[concept]
|
|
|
|
if self.has_error:
|
|
return self.sheerka.ret(self.name, False, self.error_sink)
|
|
else:
|
|
return self.sheerka.ret(self.name, True, self.concepts_grammars)
|
|
|
|
def get_concept(self, concept_name):
|
|
if concept_name in self.context.concepts_cache:
|
|
return self.context.concepts_cache[concept_name]
|
|
return self.sheerka.get(concept_name)
|
|
|
|
def get_model(self, concept_def, concepts_to_resolve):
|
|
|
|
# TODO
|
|
# inner_get_model must not modify the initial ParsingExpression
|
|
# A copy must be created
|
|
def inner_get_model(expression):
|
|
if isinstance(expression, Concept):
|
|
ret = ConceptMatch(expression, rule_name=expression.name)
|
|
concepts_to_resolve.add(expression)
|
|
elif isinstance(expression, ConceptMatch):
|
|
if expression.rule_name is None or expression.rule_name == "":
|
|
expression.rule_name = expression.concept.name if isinstance(expression.concept, Concept) \
|
|
else expression.concept
|
|
concepts_to_resolve.add(expression.concept)
|
|
ret = expression
|
|
elif isinstance(expression, str):
|
|
ret = StrMatch(expression, ignore_case=self.ignore_case)
|
|
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.extend([inner_get_model(e) for e in ret.elements])
|
|
else:
|
|
ret = self.add_error(GrammarErrorNode(f"Unrecognized grammar element '{expression}'."), False)
|
|
|
|
# Translate separator expression.
|
|
if isinstance(expression, Repetition) and expression.sep:
|
|
expression.sep = inner_get_model(expression.sep)
|
|
|
|
return ret
|
|
|
|
model = inner_get_model(concept_def)
|
|
|
|
return model
|
|
|
|
def detect_infinite_recursion(self, concepts_to_resolve):
|
|
|
|
# infinite recursion matcher
|
|
def _is_infinite_recursion(ref_concept, node):
|
|
if isinstance(node, ConceptMatch):
|
|
if node.concept == ref_concept:
|
|
return True
|
|
|
|
if isinstance(node.concept, str):
|
|
to_match = self.get_concept(node.concept)
|
|
if self.sheerka.isinstance(to_match, BuiltinConcepts.UNKNOWN_CONCEPT):
|
|
return False
|
|
else:
|
|
to_match = node.concept
|
|
|
|
return _is_infinite_recursion(ref_concept, self.concepts_grammars[to_match])
|
|
|
|
if isinstance(node, OrderedChoice):
|
|
return _is_infinite_recursion(ref_concept, node.nodes[0])
|
|
|
|
if isinstance(node, Sequence):
|
|
for node in node.nodes:
|
|
if _is_infinite_recursion(ref_concept, node):
|
|
return True
|
|
return False
|
|
|
|
return False
|
|
|
|
removed_concepts = []
|
|
for e in concepts_to_resolve:
|
|
if isinstance(e, str):
|
|
e = self.get_concept(e)
|
|
if self.sheerka.isinstance(e, BuiltinConcepts.UNKNOWN_CONCEPT):
|
|
continue
|
|
|
|
to_resolve = self.concepts_grammars[e]
|
|
if _is_infinite_recursion(e, to_resolve):
|
|
removed_concepts.append(e)
|
|
return removed_concepts
|
|
|
|
def parse(self, context, text):
|
|
if text == "":
|
|
return context.sheerka.ret(
|
|
self.name,
|
|
False,
|
|
context.sheerka.new(BuiltinConcepts.IS_EMPTY)
|
|
)
|
|
|
|
self.reset_parser(context, text)
|
|
|
|
concepts_found = [[]]
|
|
# actually list of list
|
|
# The first dimension is the number of possibilities found
|
|
# The second dimension is the number of concepts found, under one possibility
|
|
#
|
|
# Example 1
|
|
# concept foo : 'one' 'two'
|
|
# concept bar : 'one' 'two'
|
|
# input 'one two' -> will produce two possibilities (foo and bar).
|
|
#
|
|
# Example 2
|
|
# concept foo : 'one'
|
|
# concept bar : 'two'
|
|
# input 'one two' -> will produce one possibility which is (foo, bar) (foo then bar)
|
|
|
|
while True:
|
|
init_pos = self.pos
|
|
res = []
|
|
for concept, grammar in self.concepts_grammars.items():
|
|
self.seek(init_pos)
|
|
node = grammar.parse(self) # a node is TerminalNode or NonTerminalNode
|
|
if node is not None and node.end != -1:
|
|
concept_node = ConceptNode(
|
|
concept,
|
|
node.start,
|
|
node.end,
|
|
self.tokens[node.start: node.end + 1],
|
|
None,
|
|
node)
|
|
res.append(concept_node)
|
|
|
|
if len(res) == 0: # not recognized
|
|
self.seek(init_pos)
|
|
not_recognized = self.get_text_from_tokens(self.get_token())
|
|
self.add_error(self.sheerka.new(BuiltinConcepts.UNKNOWN_CONCEPT, body=not_recognized))
|
|
break
|
|
|
|
res = self.get_bests(res) # only keep the concepts that eat the more tokens
|
|
concepts_found = core.utils.product(concepts_found, res)
|
|
|
|
# loop
|
|
self.seek(res[0].end)
|
|
if not self.next_token():
|
|
break
|
|
|
|
# manage when nothing is recognized (or other error)
|
|
if self.has_error:
|
|
return self.sheerka.ret(
|
|
self.name,
|
|
False,
|
|
self.sheerka.new(
|
|
BuiltinConcepts.PARSER_RESULT,
|
|
parser=self,
|
|
source=text,
|
|
body=self.error_sink,
|
|
try_parsed=concepts_found[0] if len(concepts_found) == 1 else concepts_found))
|
|
|
|
# else
|
|
# returns as many ReturnValue than choices found
|
|
ret = []
|
|
for choice in concepts_found:
|
|
ret.append(
|
|
self.sheerka.ret(
|
|
self.name,
|
|
True,
|
|
self.sheerka.new(
|
|
BuiltinConcepts.PARSER_RESULT,
|
|
parser=self,
|
|
source=text,
|
|
body=choice,
|
|
try_parsed=choice)))
|
|
|
|
return ret[0] if len(ret) == 1 else ret
|
|
|
|
@staticmethod
|
|
def get_bests(results):
|
|
"""
|
|
Returns the result that is the longest
|
|
:param results:
|
|
:return:
|
|
"""
|
|
by_end_pos = defaultdict(list)
|
|
for result in results:
|
|
by_end_pos[result.end].append(result)
|
|
|
|
return by_end_pos[max(by_end_pos)]
|
|
|
|
|
|
class ParsingExpressionVisitor:
|
|
"""
|
|
visit ParsingExpression
|
|
"""
|
|
|
|
def visit(self, parsing_expression):
|
|
name = parsing_expression.__class__.__name__
|
|
|
|
method = 'visit_' + name
|
|
visitor = getattr(self, method, self.generic_visit)
|
|
return visitor(parsing_expression)
|
|
|
|
def generic_visit(self, parsing_expression):
|
|
if hasattr(self, "visit_all"):
|
|
self.visit_all(parsing_expression)
|
|
|
|
for node in parsing_expression.elements:
|
|
if isinstance(node, Concept):
|
|
self.visit(ConceptMatch(node.key or node.name))
|
|
elif isinstance(node, str):
|
|
self.visit(StrMatch(node))
|
|
else:
|
|
self.visit(node)
|