python / python/typing

[feature] Get the type from a variable

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#769 14 comments 74 reactions 0 assignees View on GitHub

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topic: feature
Dominant language
Python
Stars
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Forks
302
Avg merge
23h
Merged PRs (30d)
8

Description

Feature
A similar feature in typescript

const foo: number = 1
type Foo = typeof foo  // type Foo = number

function bar(x: string): void {

}

type Bar = typeof bar // type Bar = (x: string) => void

Pitch
The expected way in future python.
Possible implementation: implement __class_getitem__ for type :


foo: int = 1
Foo = type[foo]  # equivalent to Foo = int

def bar(x: string) -> None :
    ...
Bar = type[bar]  # equivalent to Bar = Callable[[str], None]

Contributor guide

No contributing guide indexed for this repository

First steps

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

Research direction

No repository file or test is named, so start with the TypeScript typeof-types reference and the discussion on this issue. Clarify the intended behavior for variables and functions under the proposed type[...] syntax; done means the typing semantics and compatibility requirements are agreed well enough to implement and test.

Written by the indexing model from the issue text.

Assessment

Tech stack
python, typescript
Domain
developer-experience
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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