revolt

Value substitutor for district42 schema

Installation

pip3 install revolt

Usage

from district42 import schema
from revolt import substitute

UserSchema = schema.dict({
    "id": schema.int,
    "name": schema.str | schema.none,
    "id_deleted": schema.bool,
})

substituted = substitute(UserSchema, {"id": 1, "name": "Bob"})

# syntax sugar
substituted = UserSchema % {"id": 1, "name": "Bob"}

Documentation

• Documentation
  • Custom Types
    • 1. Declare Schema
    • 2. Register Substitutor
    • 3. Register Representor
    • 4. Use

Custom Types

1. Declare Schema

from typing import Any
from uuid import UUID
from district42 import Props, SchemaVisitor, SchemaVisitorReturnType as ReturnType
from district42.types import Schema
from niltype import Nilable


class UUIDProps(Props):
    @property
    def value(self) -> Nilable[UUID]:
        return self.get("value")


class UUIDSchema(Schema[UUIDProps]):
    def __accept__(self, visitor: SchemaVisitor[ReturnType], **kwargs: Any) -> ReturnType:
        return visitor.visit_uuid(self, **kwargs)

    def __call__(self, /, value: UUID) -> "UUIDSchema":
        return self.__class__(self.props.update(value=value))

2. Register Substitutor

from typing import Any
from uuid import UUID
from niltype import Nil
from revolt import Substitutor


class UUIDSubstitutor(Substitutor, extend=True):
    def visit_uuid(self, schema: UUIDSchema, *, value: Any = Nil, **kwargs: Any) -> UUIDSchema:
        assert isinstance(value, UUID) and schema.props.value is Nil

        return schema.__class__(schema.props.update(value=value))

3. Register Representor

from typing import Any
from district42.representor import Representor
from niltype import Nil


class UUIDRepresentor(Representor, extend=True):
    def visit_uuid(self, schema: UUIDSchema, *, indent: int = 0, **kwargs: Any) -> str:
        r = f"{self._name}.uuid"

        if schema.props.value is not Nil:
            r += f"({schema.props.value!r})"

        return r

4. Use

from uuid import uuid4
from district42 import register_type, schema

register_type("uuid", UUIDSchema)

print(schema.uuid % uuid4())
# schema.uuid(UUID('8289806e-4f61-45a1-993b-1aa1b289735b'))

Full code available here: district42_exp_types/uuid