Pydantic Plugin: Add support for Literal and Enum types

[genro]

Feature Request

Add support for Literal and Enum types in the Pydantic plugin.

Current State

The MVP implementation (v0.6.0) supports:

• Basic types (str, int, float, bool)
• Optional and default values
• Complex types (List, Dict, Set, Tuple)
• Existing Pydantic BaseModel instances

Requested Enhancement

Support Literal and Enum for restricted value sets:

from typing import Literal
from enum import Enum

class Status(Enum):
    PENDING = "pending"
    ACTIVE = "active"
    CLOSED = "closed"

sw = Switcher().plug("pydantic")

@sw
def process_action(
    action: Literal["create", "update", "delete"],
    status: Status
):
    ...

# Valid calls
sw("process_action")("create", Status.ACTIVE)
sw("process_action")("update", "pending")  # String coerced to enum

# Invalid - should raise ValidationError
sw("process_action")("invalid", Status.ACTIVE)

Implementation Notes

• Pydantic v2 natively supports both Literal and Enum
• Should work automatically with dynamic model creation
• Test string-to-enum coercion behavior
• Ensure clear error messages for invalid values

Priority

Medium - Useful for APIs with restricted value sets.

Related

Part of the Pydantic plugin MVP+1 features discussed in initial implementation.

[genro]

Closing this issue in favor of a new one with a detailed implementation plan covering verification, testing, string-to-enum coercion, and documentation.