Files
lda-wf/src/wf_authoring/nodes/result.py
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43 lines
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Python

from __future__ import annotations
from dataclasses import dataclass
from typing import Generic, TypeVar, overload
from pydantic import BaseModel
OutputT_co = TypeVar("OutputT_co", bound=BaseModel, covariant=True)
@dataclass(frozen=True, slots=True)
class NodeReturn(Generic[OutputT_co]):
"""A node result that explicitly selects the outgoing workflow outcome."""
outcome: str
output: OutputT_co
class Nothing(BaseModel):
"""Empty output model for nodes that only choose an outcome."""
NoOutput = NodeReturn[Nothing]
"""Type alias for outcome-only nodes that return no output payload."""
@overload
def outcome(name: str) -> NodeReturn[Nothing]: ...
@overload
def outcome(name: str, output: OutputT_co) -> NodeReturn[OutputT_co]: ...
def outcome(
name: str,
output: OutputT_co | None = None,
) -> NodeReturn[OutputT_co] | NodeReturn[Nothing]:
"""Create a node result with an optional output model."""
if output is None:
return NodeReturn(outcome=name, output=Nothing())
return NodeReturn(outcome=name, output=output)