refactor: Field class independent of Metadata

frictionless/detector/detector.py

@@ -329,7 +329,7 @@ def detect_schema(
 
             # Handle name/empty
             for index, name in enumerate(names):
-                names[index] = name or f"field{index+1}"
+                names[index] = name or f"field{index + 1}"
 
             # Deduplicate names
             if len(names) != len(set(names)):
@@ -360,10 +360,11 @@ def detect_schema(
                     field.float_number = True  # type: ignore
                 elif field.type == "boolean":
                     if self.field_true_values != settings.DEFAULT_TRUE_VALUES:
-                        field.true_values = self.field_true_values  # type: ignore
+                        field._descriptor.true_values = self.field_true_values  # type: ignore
                     if self.field_false_values != settings.DEFAULT_FALSE_VALUES:
-                        field.false_values = self.field_false_values  # type: ignore
+                        field._descriptor.false_values = self.field_false_values  # type: ignore
                 runner_fields.append(field)
+
             for index, name in enumerate(names):
                 runners.append([])
                 for field in runner_fields:

frictionless/fields/boolean.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import Any, Dict, List
+from typing import List
 
 import attrs
 
@@ -29,34 +29,6 @@ class BooleanField(Field):
     true values are ["false", "False", "FALSE", "0"].
     """
 
-    # Read
-
-    def create_value_reader(self):
-        # Create mapping
-        mapping: Dict[str, bool] = {}
-        for value in self.true_values:
-            mapping[value] = True
-        for value in self.false_values:
-            mapping[value] = False
-
-        # Create reader
-        def value_reader(cell: Any):
-            if cell is True or cell is False:
-                return cell
-            if isinstance(cell, str):
-                return mapping.get(cell)
-
-        return value_reader
-
-    # Write
-
-    def create_value_writer(self):
-        # Create writer
-        def value_writer(cell: Any):
-            return self.true_values[0] if cell else self.false_values[0]
-
-        return value_writer
-
     # Metadata
 
     metadata_profile_patch = {

frictionless/schema/field.py

@@ -1,16 +1,19 @@
 from __future__ import annotations
 
+import copy
 import decimal
 import re
 from functools import partial
 from typing import TYPE_CHECKING, Any, Callable, ClassVar, Dict, List, Optional, Pattern
 
 import attrs
+import pydantic
 
 from .. import errors, settings
 from ..exception import FrictionlessException
 from ..metadata import Metadata
 from ..system import system
+from .field_descriptor import BooleanFieldDescriptor, FieldDescriptor
 
 if TYPE_CHECKING:
     from ..types import IDescriptor
@@ -22,6 +25,8 @@
 class Field(Metadata):
     """Field representation"""
 
+    _descriptor: Optional[FieldDescriptor] = None
+
     name: str
     """
     A short url-usable (and preferably human-readable) name.
@@ -50,9 +55,7 @@ class Field(Metadata):
     For example: "default","array" etc.
     """
 
-    missing_values: List[str] = attrs.field(
-        factory=settings.DEFAULT_MISSING_VALUES.copy
-    )
+    missing_values: List[str] = attrs.field(factory=settings.DEFAULT_MISSING_VALUES.copy)
     """
     List of string values to be set as missing values in the field. If any of string in missing values
     is found in the field value then it is set as None.
@@ -154,6 +157,8 @@ def cell_reader(cell: Any):
     def create_value_reader(self) -> types.IValueReader:
         # Create reader
         def value_reader(cell: Any):
+            if self._descriptor and isinstance(self._descriptor, BooleanFieldDescriptor):
+                return self._descriptor.read_value(cell)
             return cell
 
         return value_reader
@@ -192,6 +197,8 @@ def cell_writer(cell: Any, *, ignore_missing: bool = False):
     def create_value_writer(self) -> types.IValueWriter:
         # Create writer
         def value_writer(cell: Any):
+            if self._descriptor and isinstance(self._descriptor, BooleanFieldDescriptor):
+                return self._descriptor.write_value(cell)
             return str(cell)
 
         return value_writer
@@ -244,6 +251,39 @@ def metadata_transform(cls, descriptor: IDescriptor):
         if format and isinstance(format, str) and format.startswith("fmt:"):
             descriptor["format"] = format.replace("fmt:", "")
 
+    @classmethod
+    def metadata_import(
+        cls,
+        descriptor: IDescriptor,
+        *,
+        with_basepath: bool = False,
+        **options: Any,
+    ) -> "Field":
+        descriptor_copy = copy.deepcopy(descriptor)
+        field = super().metadata_import(
+            descriptor,
+            with_basepath=with_basepath,
+        )
+
+        if field.type == "boolean":
+            try:
+                field._descriptor = BooleanFieldDescriptor.model_validate(descriptor_copy)
+            except pydantic.ValidationError as ve:
+                error = errors.SchemaError(note=str(ve))
+                raise FrictionlessException(error)
+
+        return field
+
+    def to_descriptor(self, *, validate: bool = False) -> IDescriptor:
+        if self._descriptor and isinstance(self._descriptor, BooleanFieldDescriptor):
+            descr = self._descriptor.model_dump(exclude_none=True, exclude_unset=True)
+            ## Temporarily, Field properties have priority over
+            ## Field._descriptor properties
+            descr = {**descr, **super().to_descriptor(validate=validate)}
+            return descr
+        else:
+            return super().to_descriptor(validate=validate)
+
     @classmethod
     def metadata_validate(cls, descriptor: IDescriptor):  # type: ignore
         metadata_errors = list(super().metadata_validate(descriptor))
@@ -276,9 +316,7 @@ def metadata_validate(cls, descriptor: IDescriptor):  # type: ignore
                     field.false_values = descriptor["falseValues"]
             _, notes = field.read_cell(example)
             if notes is not None:
-                note = (
-                    f'example value "{example}" for field "{field.name}" is not valid'
-                )
+                note = f'example value "{example}" for field "{field.name}" is not valid'
                 yield errors.FieldError(note=note)
 
         # Misleading

frictionless/schema/field_constraints.py

@@ -0,0 +1,33 @@
+"""field_constraints.py provide pydantic Models for constraints"""
+
+from typing import Any, Dict, Generic, List, Optional, TypeVar, Union
+
+import pydantic
+
+T = TypeVar("T")
+
+
+class BaseConstraints(pydantic.BaseModel, Generic[T]):
+    required: Optional[bool] = None
+    unique: Optional[bool] = None
+    enum: Optional[List[Union[str, T]]] = None
+
+
+class CollectionConstraints(BaseConstraints[str]):
+    minLength: Optional[int] = None
+    maxLength: Optional[int] = None
+
+
+class JSONConstraints(CollectionConstraints):
+    jsonSchema: Optional[Dict[str, Any]] = None
+
+
+class StringConstraints(CollectionConstraints):
+    pattern: Optional[str] = None
+
+
+class ValueConstraints(BaseConstraints[T], Generic[T]):
+    minimum: Optional[Union[str, T]] = None
+    maximum: Optional[Union[str, T]] = None
+    exclusiveMinimum: Optional[Union[str, T]] = None
+    exclusiveMaximum: Optional[Union[str, T]] = None