import logging
import re
from dataclasses import dataclass
from enum import Enum
from typing import TYPE_CHECKING, ClassVar, Optional
if TYPE_CHECKING:
from rhoknp import Clause, Sentence
logger = logging.getLogger(__name__)
[docs]
class DiscourseRelationLabel(Enum):
"""談話関係ラベルを表す列挙体．"""
NO_RELATION = "談話関係なし"
CAUSE_REASON = "原因・理由"
PURPOSE = "目的"
CONDITION = "条件"
EVIDENCE = "根拠"
CONTRAST = "対比"
CONCESSION = "逆接"
[docs]
class DiscourseRelationTag(Enum):
"""談話関係タグを表す列挙体．"""
NO_RELATION = "談話関係なし"
CAUSE_REASON = "原因・理由"
CAUSE_REASON_FORWARD = "原因・理由(順方向)"
CAUSE_REASON_BACKWARD = "原因・理由(逆方向)"
CAUSE_REASON_BACKWARD2 = "原因・理由-逆"
PURPOSE = "目的"
PURPOSE_FORWARD = "目的(順方向)"
PURPOSE_BACKWARD = "目的(逆方向)"
CONDITION = "条件"
CONDITION_FORWARD = "条件(順方向)"
CONDITION_BACKWARD = "条件(逆方向)"
NEGATIVE_CONDITION = "否定条件"
CONTRAST = "対比"
CONTRAST_NO_DIRECTION = "対比(方向なし)"
CONCESSION = "逆接"
CONCESSION_FORWARD = "逆接・譲歩(順方向)"
CONCESSION_BACKWARD = "逆接・譲歩(逆方向)"
CONCESSIVE_CONDITION = "条件-逆条件"
EVIDENCE = "根拠"
EVIDENCE_FORWARD = "その他根拠(順方向)"
EVIDENCE_BACKWARD = "その他根拠(逆方向)"
[docs]
@classmethod
def has_value(cls, value: str) -> bool:
"""指定された値が存在すれば True．
Args:
value: 談話関係タグ．
"""
return any(value == item.value for item in cls)
@property
def label(self) -> DiscourseRelationLabel:
"""タグに対応する談話関係のラベルを返却．"""
if self in {
DiscourseRelationTag.NO_RELATION,
}:
return DiscourseRelationLabel.NO_RELATION
elif self in {
DiscourseRelationTag.CAUSE_REASON,
DiscourseRelationTag.CAUSE_REASON_FORWARD,
DiscourseRelationTag.CAUSE_REASON_BACKWARD,
DiscourseRelationTag.CAUSE_REASON_BACKWARD2,
}:
return DiscourseRelationLabel.CAUSE_REASON
elif self in {
DiscourseRelationTag.PURPOSE,
DiscourseRelationTag.PURPOSE_FORWARD,
DiscourseRelationTag.PURPOSE_BACKWARD,
}:
return DiscourseRelationLabel.PURPOSE
elif self in {
DiscourseRelationTag.CONDITION,
DiscourseRelationTag.CONDITION_FORWARD,
DiscourseRelationTag.CONDITION_BACKWARD,
DiscourseRelationTag.NEGATIVE_CONDITION,
}:
return DiscourseRelationLabel.CONDITION
elif self in {
DiscourseRelationTag.CONTRAST,
DiscourseRelationTag.CONTRAST_NO_DIRECTION,
}:
return DiscourseRelationLabel.CONTRAST
elif self in {
DiscourseRelationTag.CONCESSION,
DiscourseRelationTag.CONCESSION_FORWARD,
DiscourseRelationTag.CONCESSION_BACKWARD,
DiscourseRelationTag.CONCESSIVE_CONDITION,
}:
return DiscourseRelationLabel.CONCESSION
elif self in {
DiscourseRelationTag.EVIDENCE,
DiscourseRelationTag.EVIDENCE_FORWARD,
DiscourseRelationTag.EVIDENCE_BACKWARD,
}:
return DiscourseRelationLabel.EVIDENCE
raise AssertionError # unreachable
[docs]
def is_swap_needed(self) -> bool:
"""談話関係が逆方向であれば True．"""
return self in {
DiscourseRelationTag.CAUSE_REASON_BACKWARD,
DiscourseRelationTag.CAUSE_REASON_BACKWARD2,
DiscourseRelationTag.PURPOSE_BACKWARD,
DiscourseRelationTag.CONDITION_BACKWARD,
DiscourseRelationTag.CONCESSION_BACKWARD,
DiscourseRelationTag.EVIDENCE_BACKWARD,
}
[docs]
@dataclass
class DiscourseRelation:
"""談話関係クラス"""
CLAUSE_FUNCTION_PAT: ClassVar[re.Pattern] = re.compile(r"節-機能-(?P<label>.+)")
BACKWARD_CLAUSE_FUNCTION_PAT: ClassVar[re.Pattern] = re.compile(r"節-前向き機能-(?P<label>.+)")
DISCOURSE_RELATION_PAT: ClassVar[re.Pattern] = re.compile(
r"(?P<sid>[^/]+)/(?P<base_phrase_index>\d+)/(?P<tag>[^/]+)"
)
sid: str #: 主辞の文ID．
base_phrase_index: int #: 主辞の基本句インデックス．
label: DiscourseRelationLabel #: 談話関係ラベル．
tag: DiscourseRelationTag #: 談話関係タグ．
modifier: "Clause" #: 修飾節．
head: "Clause" #: 主辞節．
is_explicit: bool = False #: 明示的な談話関係ならTrue．．
def __hash__(self) -> int:
return hash((self.label, self.modifier, self.head))
def __eq__(self, other: object) -> bool:
if not isinstance(other, type(self)):
return False
return self.label == other.label and self.modifier == other.modifier and self.head == other.head
[docs]
@classmethod
def from_clause_function_fstring(cls, fstring: str, modifier: "Clause") -> Optional["DiscourseRelation"]:
"""節機能を表す素性文字列から初期化．
Args:
fstring: 節機能を表す素性文字列．
modifier: 修飾節．
.. note::
節機能由来で認定された談話関係は明示的 (explicit) とみなす．
"""
match = cls.CLAUSE_FUNCTION_PAT.match(fstring)
if match is None:
return None
label = match["label"]
if not DiscourseRelationTag.has_value(label):
return None
tag = DiscourseRelationTag(label)
label = tag.label
head = modifier.parent
if head is None:
return None
if tag.is_swap_needed():
# NOTE: Currently, no clause function requires swap.
modifier, head = head, modifier # pragma: no cover
return cls(
sid=modifier.sentence.sid,
base_phrase_index=head.end.index,
label=label,
tag=tag,
modifier=modifier,
head=head,
is_explicit=True,
)
[docs]
@classmethod
def from_backward_clause_function_fstring(cls, fstring: str, head: "Clause") -> Optional["DiscourseRelation"]:
"""前向き節機能を表す素性文字列から初期化．
Args:
fstring: 前向き節機能を表す素性文字列．
head: 主節．
.. note::
前向き節機能由来で認定された談話関係は明示的 (explicit) とみなす．
"""
match = cls.BACKWARD_CLAUSE_FUNCTION_PAT.match(fstring)
if match is None:
return None
label = match["label"]
if not DiscourseRelationTag.has_value(label):
return None
tag = DiscourseRelationTag(label)
label = tag.label
if not head.sentence.has_document():
return None # cannot find modifier
if head.sentence.index == 0:
return None # cannot find modifier
modifier = head.sentence.document.sentences[head.sentence.index - 1].clauses[-1]
if tag.is_swap_needed():
modifier, head = head, modifier
return cls(
sid=head.sentence.sid,
base_phrase_index=head.end.index,
label=label,
tag=tag,
modifier=modifier,
head=head,
is_explicit=True,
)
[docs]
@classmethod
def from_discourse_relation_fstring(cls, fstring: str, modifier: "Clause") -> Optional["DiscourseRelation"]:
"""談話関係を表す素性文字列から初期化．
Args:
fstring: 談話関係を表す素性文字列．
modifier: 修飾節．
"""
match = re.match(cls.DISCOURSE_RELATION_PAT, fstring)
if match is None:
logger.warning(f"'{fstring}' is not a valid discourse relation fstring")
return None
sid = match["sid"]
base_phrase_index = int(match["base_phrase_index"])
tag = match["tag"]
if not DiscourseRelationTag.has_value(tag):
logger.warning(f"unknown discourse relation label '{tag}' found")
return None
tag = DiscourseRelationTag(tag)
category = tag.label
head_sentence: "Sentence" | None = None
if modifier.sentence.has_document():
sentences = modifier.document.sentences
else:
sentences = [modifier.sentence]
for sentence in sentences:
if sentence.sid == sid:
head_sentence = sentence
break
if head_sentence is None:
logger.warning(f"{sid} not found")
return None
if base_phrase_index >= len(head_sentence.base_phrases):
logger.warning(f"index out of range in {sid}")
return None
head_base_phrase = head_sentence.base_phrases[base_phrase_index]
head = head_base_phrase.clause
if head.end != head_base_phrase:
logger.warning(f"invalid clause tag in {sid}")
return None
if tag.is_swap_needed():
modifier, head = head, modifier
return cls(sid, base_phrase_index, category, tag, modifier, head)
[docs]
def to_fstring(self) -> str:
"""談話関係を素性文字列に変換する．"""
return f"<談話関係:{self.sid}/{self.base_phrase_index}/{self.label.value}>"