Metadata-Version: 2.1
Name: pyre-extensions
Version: 0.0.5
Summary: Type system extensions for use with the pyre type checker
Home-page: https://github.com/pypa/sampleproject
Author: Facebook
Author-email: pyre@fb.com
License: UNKNOWN
Platform: UNKNOWN
Classifier: Development Status :: 3 - Alpha
Classifier: Environment :: Console
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: MIT License
Classifier: Programming Language :: Python
Classifier: Topic :: Software Development
Classifier: Operating System :: OS Independent
Description-Content-Type: text/markdown

# Pyre Extensions
This module defines extensions to the standard “typing” module that are supported by the [Pyre typechecker](https://pypi.org/project/pyre-check/).

## ArgSpec 
ArgSpecs are a special kind of type variable that captures callable parameter specifications
(known as argspecs in the runtime) instead of types, allowing the typing of decorators which 
transform the return type of the given callable.  
For example:
```
from typing import TypeVar, Callable, List
from pyre_extensions import ArgSpec
Tparams = ArgSpec("Tparams")
Treturn = TypeVar("Treturn")
def unwrap(f: Callable[Tparams, List[Treturn]) -> Callable[Tparams, Treturn]: ...
@unwrap
def foo(x: int, y: str, z: bool = False) -> List[int]:
    return [1, 2, 3]
```
decorates foo into a callable that returns int, but still has the same parameters, including their 
names and whether they are required.


