chore: minor refactor incl. explicit typing (#39)

Signed-off-by: Panos Vagenas <[email protected]>

docling_core/transforms/chunker/base.py

@@ -4,12 +4,17 @@
 #
 
 """Define base classes for chunking."""
+import re
 from abc import ABC, abstractmethod
-from typing import Iterator, Optional
+from typing import Final, Iterator, Optional
 
-from pydantic import BaseModel, model_validator
+from pydantic import BaseModel, Field, field_validator
 
 from docling_core.types import BoundingBox, Document
+from docling_core.types.base import _JSON_POINTER_REGEX
+
+# (subset of) JSONPath format, e.g. "$.main-text[84]" (for migration purposes)
+_DEPRECATED_JSON_PATH_PATTERN: Final = re.compile(r"^\$\.([\w-]+)\[(\d+)\]$")
 
 
 def _create_path(pos: int, path_prefix: str = "main-text") -> str:
@@ -19,21 +24,21 @@ def _create_path(pos: int, path_prefix: str = "main-text") -> str:
 class Chunk(BaseModel):
     """Data model for Chunk."""
 
-    path: str
+    path: str = Field(pattern=_JSON_POINTER_REGEX)
     text: str
     heading: Optional[str] = None
 
-    @model_validator(mode="before")
+    @field_validator("path", mode="before")
     @classmethod
-    def _json_pointer_from_json_path(cls, data):
-        path = data.get("path")
-        if path.startswith("$."):
-            parts = path.split("[")
-            data["path"] = _create_path(
-                pos=parts[1][:-1],
-                path_prefix=parts[0][2:],
-            )
-        return data
+    def _json_pointer_from_json_path(cls, path: str):
+        if (match := _DEPRECATED_JSON_PATH_PATTERN.match(path)) is not None:
+            groups = match.groups()
+            if len(groups) == 2 and groups[0] is not None and groups[1] is not None:
+                return _create_path(
+                    pos=int(groups[1]),
+                    path_prefix=groups[0],
+                )
+        return path
 
 
 class ChunkWithMetadata(Chunk):

docling_core/transforms/metadata_extractor/simple_metadata_extractor.py

@@ -6,13 +6,13 @@
 """Simple metadata extractor module."""
 
 
-from typing import Any
+from typing import Any, Final
 
 from docling_core.transforms.metadata_extractor import BaseMetadataExtractor
 from docling_core.types import Document as DLDocument
 
-_DL_DOC_HASH = "dl_doc_hash"
-_ORIGIN = "origin"
+_DL_DOC_HASH: Final[str] = "dl_doc_hash"
+_ORIGIN: Final[str] = "origin"
 
 
 class SimpleMetadataExtractor(BaseMetadataExtractor):

docling_core/types/base.py

@@ -6,7 +6,7 @@
 """Define common models across types."""
 from datetime import datetime, timezone
 from enum import Enum
-from typing import Generic, Hashable, List, Literal, Optional, TypeVar
+from typing import Final, Generic, Hashable, List, Literal, Optional, TypeVar
 
 from pydantic import (
     AfterValidator,
@@ -28,6 +28,9 @@
 from docling_core.utils.alias import AliasModel
 from docling_core.utils.validators import validate_datetime, validate_unique_list
 
+# (subset of) JSON Pointer URI fragment id format, e.g. "#/main-text/84":
+_JSON_POINTER_REGEX: Final[str] = r"^#(?:/([\w-]+)(?:/(\d+))?)?$"
+
 LanguageT = TypeVar("LanguageT", bound=str)
 IdentifierTypeT = TypeVar("IdentifierTypeT", bound=str)
 DescriptionAdvancedT = TypeVar("DescriptionAdvancedT", bound=BaseModel)

docling_core/types/experimental/document.py

@@ -20,6 +20,7 @@
 from typing_extensions import Annotated
 
 from docling_core.search.package import VERSION_PATTERN
+from docling_core.types.base import _JSON_POINTER_REGEX
 from docling_core.types.doc.tokens import DocumentToken
 from docling_core.types.experimental import BoundingBox, Size
 from docling_core.types.experimental.labels import DocItemLabel, GroupLabel
@@ -28,9 +29,6 @@
 LevelNumber = typing.Annotated[int, Field(ge=1, le=100)]
 CURRENT_VERSION: Final = "1.0.0"
 
-# (subset of) JSON Pointer URI fragment identifier format:
-_JSON_POINTER_REGEX = r"^#(/[\w\-]+(/\d+)?)?$"
-
 
 class BasePictureData(BaseModel):  # TBD
     """BasePictureData."""

test/test_chunk.py

@@ -0,0 +1,16 @@
+#
+# Copyright IBM Corp. 2024 - 2024
+# SPDX-License-Identifier: MIT
+#
+
+from docling_core.transforms.chunker.base import Chunk
+
+
+def test_chunk_migration():
+    input_path = "$.main-text[42]"  # deprected path format
+    expected_path = "#/main-text/42"
+    chunk = Chunk(
+        path=input_path,
+        text="foo",
+    )
+    assert chunk.path == expected_path