Typeclasses with several methods

Open

#83 opened on Jun 24, 2020 2 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty: 5/5
Estimated time: Over a week
Newbie friendliness: 25/100

Issue type: Feature
Clarity: Mostly clear
Activity status: Stale
Tech stack: python
Domain: tooling

Research direction

No files, tests, or entry points are named. Start by tracing how the current typeclass mechanism represents and binds implementations, then determine how a Python Protocol with several methods, including the classmethod, should be supported. Done means the proposed Functor shape works and its implementation binding is defined and covered by tests.

Written by the indexing model from the issue text.

Description

enhancement help wanted

There's a common use-case when we need to create a type-class with several methods. Like:

class Functor(Protocol[T]):
    def map(self, function: Callable[[T], Functor[V]]) -> Functor[V]:
        ...

    @classmethod
    def from_value(cls, inner_value: V) -> Functor[V]:
        ...

Currently, there's no way we can do that.

I propose something like this:

@typeclass
class Functor(Protocol[T]):
    def map(self, function: Callable[[T], Functor[V]]) -> Functor[V]:
        ...

    @classmethod
    def from_value(cls, inner_value: V) -> Functor[V]:
        ...

I am not sure how to bound it to the actual implementation.

Dominant language: Python
Stars: 730
Forks: 30
PR merge metrics: No merged PRs in 30d

Contributor guide

Open the contributing guide

First steps

Read the whole issue, then the project's contributing guide.
Comment on the issue to say you are picking it up — it saves two people doing the same work.
Fork the repository and make your change on a branch.
Open a pull request that references the issue number.

Similar issues

Calibration reader uses the wrong batches after set_range and cannot replay bounded ranges Open

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

microsoft/Olive#2688 · Opened Sep 25, 2026
Registry special-param check rejects PEP 604 `X | None` (only unwraps typing.Union) Open

Difficulty 2/5 1-3 hours Newbie friendliness 86/100

browser-use/browser-use#5905 · Opened Sep 25, 2026
Set header user-agent to AYON API version Open

type: enhancement

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

ynput/ayon-python-api#363 · Opened Sep 25, 2026
load_pretrained_model deep-copies the whole state dict, doubling peak load memory Open

bug needs triage

Difficulty 2/5 1-3 hours Newbie friendliness 88/100

modelscope/FunASR#3728 · Opened Sep 25, 2026
[Bug] FollowBench post-processing runs eval() on model output (arbitrary code execution) Open

Difficulty 2/5 1-3 hours Newbie friendliness 88/100

open-compass/opencompass#2655 · Opened Sep 25, 2026

More Python issues