https://github.com/15r10nk/lazy-imports-lite
lazy-imports-lite changes the semantics of python imports and defers the import until it is used the first time like in PEP 690
https://github.com/15r10nk/lazy-imports-lite
Last synced: 6 months ago
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lazy-imports-lite changes the semantics of python imports and defers the import until it is used the first time like in PEP 690
- Host: GitHub
- URL: https://github.com/15r10nk/lazy-imports-lite
- Owner: 15r10nk
- Created: 2024-02-07T07:42:39.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2025-01-07T00:34:17.000Z (9 months ago)
- Last Synced: 2025-01-07T01:24:34.230Z (9 months ago)
- Language: Python
- Size: 70.3 KB
- Stars: 11
- Watchers: 1
- Forks: 0
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- Funding: .github/FUNDING.yml
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README
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**lazy-imports-lite** changes the semantics of python imports and defers the import until it is used the first time like in [PEP 690](https://peps.python.org/pep-0690).
I liked the idea of lazy imports and wanted to use them for my projects without having to change my code.
I hope this project allows more people to use lazy imports in their projects.
> [!NOTE]
> It is important to note that this project is not affiliated in any way with the original PEP.
> I hope this project allows a wider adoption of lazy imports, but there is currently no plan to standardize it.
> [!IMPORTANT]
> **lazy-imports-lite** is still in early development and may contain bugs.
> Make sure to test your code carefully before you use it.
## Key Features
- lazy imports almost like [PEP 690](https://peps.python.org/pep-0690)
- no code changes required
- can be enabled per module (by keyword in the package)
How is it different to PEP 690?
- It has not the same performance as the implementation from the pep. Every access to parts of imported modules is transformed to an attribute access `x` -> `x._lazy_value`.
- Exceptions during deferred import are converted to `LazyImportError`.
- modules which use `exec` or `eval` can not be transformed.
## Usage
- add `lazy-imports-lite` to your project dependencies.
- add lazy-imports-lite-enabled to the keywords of your `pyproject.toml`.
```
[project]
keywords=["lazy-imports-lite-enabled"]
```
This enables lazy imports for all top-level imports in your modules in your project.
One way to verify if it is enabled is to check which loader is used.
``` pycon
>>> import your_project
>>> print(type(your_project.__spec__.loader))
```
## Implementation
`lazy-imports-lite` works by rewriting the AST at runtime before the code is compiled.
The following code:
``` python
from foo import bar
def f():
print(bar())
```
is internally transformed to:
``` python
import lazy_imports_lite._hooks as __lazy_imports_lite__
globals = __lazy_imports_lite__.make_globals(lambda g=globals: g())
bar = __lazy_imports_lite__.ImportFrom(__package__, "foo", "bar")
def f():
print(bar._lazy_value())
```
This transformation should be never visible to you (the source location is preserved) but it is good to know if something does not work as expected.
You can view a preview of this transformation with `lazy-imports-lite preview ` if you want to know how your code would be changed.
## TODO
- [ ] mutable `globals()`
- [ ] cache generated bytecode
## Issues
If you encounter any problems, please [report an issue](https://github.com/15r10nk/lazy-imports-lite/issues) along with a detailed description.
## License
Distributed under the terms of the [MIT](http://opensource.org/licenses/MIT) license, "lazy-imports-lite" is free and open source software.