Mapper

mapper

Mapper Protocol for generic object transformation.

Mapper

Bases: Protocol

Protocol for mapping objects from one type to another.

Mappers encapsulate transformation logic between types. This is a
foundational abstraction that can be used across any context where
object transformation is needed.

Variance is inferred automatically by the type checker from usage.

---

Type Parameters

• SourceType — The input type to be transformed.
• TargetType — The output type after transformation.

Example

class UserDTO:
    def __init__(self, username: str, email: str):
        self.username = username
        self.email = email


class User:
    def __init__(self, name: str, contact_email: str):
        self.name = name
        self.contact_email = contact_email


class UserMapper(Mapper[UserDTO, User]):
    def map(self, source: UserDTO) -> User:
        return User(
            name=source.username,
            contact_email=source.email,
        )


mapper = UserMapper()
dto = UserDTO(username="alice", email="alice@example.com")
user = mapper.map(dto)

Source code in src/forging_blocks/foundation/mapper.py

class Mapper[SourceType, TargetType](Protocol):
    """Protocol for mapping objects from one type to another.

    Mappers encapsulate transformation logic between types. This is a
    foundational abstraction that can be used across any context where
    object transformation is needed.

    Variance is inferred automatically by the type checker from usage.

    ---
    **Type Parameters**
    -------------------
    - **SourceType** — The input type to be transformed.
    - **TargetType** — The output type after transformation.

    Example:
        ```python
        class UserDTO:
            def __init__(self, username: str, email: str):
                self.username = username
                self.email = email


        class User:
            def __init__(self, name: str, contact_email: str):
                self.name = name
                self.contact_email = contact_email


        class UserMapper(Mapper[UserDTO, User]):
            def map(self, source: UserDTO) -> User:
                return User(
                    name=source.username,
                    contact_email=source.email,
                )


        mapper = UserMapper()
        dto = UserDTO(username="alice", email="alice@example.com")
        user = mapper.map(dto)
        ```
    """

    def map(self, source: SourceType) -> TargetType:
        """Transform a source object into a target object.

        Args:
            source: The source object to be transformed.

        Returns:
            The transformed target object.

        """
        ...

map(source: SourceType) -> TargetType

Transform a source object into a target object.

Parameters:

Name	Type	Description	Default
source	SourceType	The source object to be transformed.	required

Returns:

Type	Description
TargetType	The transformed target object.

Source code in src/forging_blocks/foundation/mapper.py

def map(self, source: SourceType) -> TargetType:
    """Transform a source object into a target object.

    Args:
        source: The source object to be transformed.

    Returns:
        The transformed target object.

    """
    ...