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PiperOrigin-RevId: 630460036

nisaba/scripts/natural_translit/utils/BUILD.bazel

@@ -246,6 +246,30 @@ py_test(
     ],
 )
 
+py_library(
+    name = "alignment2",
+    srcs = ["alignment2.py"],
+    deps = [
+        ":expression",
+        ":operation",
+        ":type_op",
+    ],
+)
+
+py_test(
+    name = "alignment2_test",
+    srcs = ["alignment2_test.py"],
+    main = "alignment2_test.py",
+    deps = [
+        ":alignment2",
+        ":expression",
+        ":operation",
+        ":symbol",
+        ":test_op",
+        "@io_abseil_py//absl/testing:absltest",
+    ],
+)
+
 py_library(
     name = "test_op",
     srcs = ["test_op.py"],

nisaba/scripts/natural_translit/utils/alignment2.py

@@ -0,0 +1,358 @@
+# Copyright 2024 Nisaba Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Alignment class for defining a relation between two expressions.
+
+Attributes:
+  alias: Alias of the Expression.
+  left: Left side of the Alignment.
+  right: Right side of the Alignment.
+  preceding: Preceding context.
+  following: Following context.
+  from_bos: If True, preceding context starts from the beginning of the
+    sequence.
+  to_eos: If True, the following context ends at the end of the sequence.
+  operation: Operation that represents the relation between the sides of the
+    alignment.
+  priority: Priority of the alignment. When the applied cost of multiple
+    rules are equal, the rule with the highest priority will be applied.
+  applied_cost: Cost of the alignment when it's applied in context.
+  source: Source of the alignment.
+
+For inspection and debugging purposes, alignments are represented as strings in
+  the following format:
+
+([<preceding context>] <input>:<output> [<following context>], operation)
+
+Alignments can be defined in an inventory as a set of rules to build grammars,
+  or to assess the structural correspondence of two expressions.
+
+Example:
+  `([grapheme:nasal] a:b [grapheme:vowel], alignable (0.00))` means that
+  expression `a` is rewritten as expression `b` with `alignable` operation with
+  0 cost when it's preceded by a grapheme that corresponds to a nasal and
+  followed by a grapheme that corresponds to a vowel.
+
+Alignment sources:
+  ALIGNER: Alignments from an aligner output that doesn't correspond to a
+    predefined rule. Eg. identity or token boundary alignments.
+  CONSTANT: Alignment class constants.
+  ENGLISH: English alignables.
+  FOREIGN: Alignables for foreign languages other than English
+  LEXICON: Alignables that come from a lexicon that will be prioritised over
+    other rules. Eg. frequent affixes or high profile entity names.
+  NATIVE: Alignables for the native language.
+  SPELLOUT: Alignables for spelled out letters.
+  UNSPECIFIED = Alignments from an unspecified source.
+"""
+
+import enum
+# from typing import Union
+from nisaba.scripts.natural_translit.utils import expression as exp
+from nisaba.scripts.natural_translit.utils import operation as op
+# from nisaba.scripts.natural_translit.utils
+# import type_op as ty
+
+
+class Alignment(exp.Expression):
+  """An Expression that represents an alignment of exp.Expressions."""
+
+  class Source(enum.StrEnum):
+    ALIGNER = 'aligner'
+    CONSTANT = 'constant'
+    ENGLISH = 'english'
+    FOREIGN = 'foreign'
+    LEXICON = 'lexicon'
+    NATIVE = 'native'
+    SPELLOUT = 'spellout'
+    UNSPECIFIED = 'unspecified'
+
+  def __init__(self, alias: str = ''):
+    super().__init__(alias)
+    self.left = exp.Expression.ANY
+    self.right = exp.Expression.ANY
+    self.preceding = exp.Expression.ANY
+    self.following = exp.Expression.ANY
+    self.from_bos = False
+    self.to_eos = False
+    self.operation = op.Operation.COMMON.unassigned
+    self.priority = 0
+    self.applied_cost = self.operation.base_cost
+    self.source = Alignment.Source.UNSPECIFIED
+
+  def _side_str(self, side: exp.Expression) -> str:
+    if side.is_any() or len(side) != 1:
+      return str(side)
+    return side.item(0).text
+
+  def _context_str(self, context: exp.Expression) -> str:
+    if context.is_any() or not isinstance(context, Alignment):
+      return ''
+    return '%s:%s' % (
+        self._side_str(context.left),
+        self._side_str(context.right),
+    )
+
+  def _pre_str(self) -> str:
+    text = self._context_str(self.preceding)
+    prefix = exp.Atomic.CTRL.bos.text if self.from_bos else ''
+    return '[%s%s] ' % (prefix, text) if text else ''
+
+  def _fol_str(self) -> str:
+    text = self._context_str(self.following)
+    suffix = exp.Atomic.CTRL.eos.text if self.to_eos else ''
+    return ' [%s%s]' % (text, suffix) if text else ''
+
+  def __str__(self):
+    if self.operation.is_assigned():
+      operation = ', %s' % str(self.operation)
+    else:
+      operation = ''
+    return '(%s%s:%s%s%s)' % (
+        self._pre_str(),
+        self._side_str(self.left),
+        self._side_str(self.right),
+        self._fol_str(),
+        operation,
+    )
+
+  def tsv_row(self) -> str:
+    return '\t'.join([
+        self.alias,
+        ''.join([item.text for item in self.left]),
+        ''.join([item.text for item in self.right]),
+        str(self.operation.match),
+        str(self.applied_cost),
+    ])
+
+  def _set_side(self, side: exp.Expression.OR_SYMBOL) -> exp.Expression:
+    if not isinstance(side, exp.Expression):
+      return exp.Atomic.read(side)
+    return side
+
+  @classmethod
+  def simple(
+      cls,
+      left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+      right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+  ) -> 'Alignment':
+    alignment = cls()
+    alignment.left = alignment._set_side(left)
+    alignment.right = alignment._set_side(right)
+    return alignment
+
+#   @classmethod
+#   def constant(
+#       cls,
+#       alias: str = '',
+#       left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       operation: op.Operation = op.Operation.COMMON.unassigned,
+#   ) -> 'Alignment':
+#     alignment = cls(alias)
+#     alignment.left = alignment._set_side(left)
+#     alignment.right = alignment._set_side(right)
+#     alignment.operation = operation
+#     alignment.source = Alignment.Source.CONSTANT
+#     return alignment
+
+  # TODO: Expand context to allow Cat and Or of alignments.
+  # Eg. a rule with `preceding=((vowel_grapheme:any) | (any:vowel_phoneme)))`
+  # will apply if it's preceded by an alignment that has a vowel grapheme on the
+  # left side or a vowel phoneme on the right side, regardless of what they are
+  # aligned with.
+#   def _set_context(
+#       self, left: exp.Expression.OR_SYMBOL, right: exp.Expression.OR_SYMBOL
+#   ) -> 'Alignment':
+#     if left.is_any() and right.is_any():
+#       return Alignment.ANY
+#     return Alignment.simple(left, right)
+
+#   @classmethod
+#   def rule(
+#       cls,
+#       alias: str = '',
+#       left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       preceding_left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       preceding_right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       following_left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       following_right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       from_bos: bool = False,
+#       to_eos: bool = False,
+#       operation: op.Operation = op.Operation.COMMON.alignable,
+#       priority: int = 0,
+#       applied_cost: Union[float, ty.Nothing] = ty.UNSPECIFIED,
+#       source: Source = Source.UNSPECIFIED,
+#   ) -> 'Alignment':
+#     rule = cls()
+#     rule.alias = alias
+#     rule.left = rule._set_side(left)
+#     rule.right = rule._set_side(right)
+#     rule.preceding = rule._set_context(preceding_left, preceding_right)
+#     rule.following = rule._set_context(following_left, following_right)
+#     rule.from_bos = from_bos
+#     rule.to_eos = to_eos
+#     rule.operation = operation
+#     rule.priority = priority
+#     if isinstance(applied_cost, float):
+#       rule.applied_cost = applied_cost
+#     else:
+#       rule.applied_cost = rule.operation.base_cost
+#     rule.source = source
+#     return rule
+
+#   @classmethod
+#   def deletion(
+#       cls,
+#       alias: str = '',
+#       left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       preceding_left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       preceding_right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       following_left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       following_right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       from_bos: bool = False,
+#       to_eos: bool = False,
+#       operation: op.Operation = op.Operation.COMMON.deletion,
+#       priority: int = 0,
+#       applied_cost: Union[int, float, ty.Nothing] = ty.UNSPECIFIED,
+#       source: Source = Source.UNSPECIFIED,
+#   ) -> 'Alignment':
+#     return cls.rule(
+#         alias,
+#         left,
+#         exp.Atomic.CTRL.eps,
+#         preceding_left,
+#         preceding_right,
+#         following_left,
+#         following_right,
+#         from_bos,
+#         to_eos,
+#         operation,
+#         priority,
+#         applied_cost,
+#         source,
+#     )
+
+#   @classmethod
+#   def insertion(
+#       cls,
+#       alias: str = '',
+#       right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       preceding_left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       preceding_right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       following_left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       following_right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       from_bos: bool = False,
+#       to_eos: bool = False,
+#       operation: op.Operation = op.Operation.COMMON.insertion,
+#       priority: int = 0,
+#       applied_cost: Union[int, float, ty.Nothing] = ty.UNSPECIFIED,
+#       source: Source = Source.UNSPECIFIED,
+#   ) -> 'Alignment':
+#     return cls.rule(
+#         alias,
+#         exp.Atomic.CTRL.eps,
+#         right,
+#         preceding_left,
+#         preceding_right,
+#         following_left,
+#         following_right,
+#         from_bos,
+#         to_eos,
+#         operation,
+#         priority,
+#         applied_cost,
+#         source,
+#     )
+
+#   @classmethod
+#   def interchangeable(
+#       cls,
+#       alias: str = '',
+#       left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       preceding_left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       preceding_right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       following_left: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       following_right: exp.Expression.OR_SYMBOL = exp.Expression.ANY,
+#       from_bos: bool = False,
+#       to_eos: bool = False,
+#       operation: op.Operation = op.Operation.COMMON.interchangeable,
+#       priority: int = 0,
+#       applied_cost: Union[int, float, ty.Nothing] = ty.UNSPECIFIED,
+#       source: Source = Source.UNSPECIFIED,
+#   ) -> tuple['Alignment', 'Alignment']:
+#     common = (
+#         preceding_left,
+#         preceding_right,
+#         following_left,
+#         following_right,
+#         from_bos,
+#         to_eos,
+#         operation,
+#         priority,
+#         applied_cost,
+#         source,
+#     )
+#     left_to_right = cls.rule(alias + '_l2r', left, right, *common)
+#     right_to_left = cls.rule(alias + '_r2l', right, left, *common)
+#     return left_to_right, right_to_left
+
+#   def is_any(self) -> bool:
+#     return self.left.is_any() and self.right.is_any()
+
+#   def is_eps(self) -> bool:
+#     return self.left.is_eps() and self.right.is_eps()
+
+#   def is_nor(self) -> bool:
+#     return self.left.is_nor() and self.right.is_nor()
+
+#   def _copy_context(
+#       self, context: exp.Expression
+#   ) -> tuple[exp.Expression, exp.Expression]:
+#     if isinstance(context, Alignment):
+#       return context.left.copy(), context.right.copy()
+#     return exp.Expression.ANY, exp.Expression.ANY
+
+#   def copy(self) -> 'Alignment':
+#     if (
+#         self == Alignment.ANY
+#         or self == Alignment.EPSILON
+#         or self == Alignment.ERROR
+#     ):
+#       return self
+#     return Alignment.rule(
+#         self.alias,
+#         self.left.copy(),
+#         self.right.copy(),
+#         *self._copy_context(self.preceding),
+#         *self._copy_context(self.following),
+#         self.from_bos,
+#         self.to_eos,
+#         self.operation,
+#         self.priority,
+#         self.applied_cost,
+#         self.source,
+#     )
+
+
+# Alignment.ANY = Alignment.constant('any')
+# Alignment.EPSILON = Alignment.constant(
+#     'empty', exp.Atomic.CTRL.eps, exp.Atomic.CTRL.eps
+# )
+# Alignment.ERROR = Alignment.constant(
+#     'error',
+# exp.Atomic.CTRL.nor, exp.Atomic.CTRL.nor, op.Operation.COMMON.error
+# )