Trouting

Trouting (short for Type Routing) is a simple class decorator that allows to define multiple interfaces for a method that behave differently depending on input types.

To install for PyPI trouting, run:

pip install trouting

The logo of trouting was generated using Stable Diffusion with prompt "A Kandinsky painting titled The Trout Who Routes" and slightly edited by the author.

Example

Imagine you want to define a class whose method behaves differently depending on whether the input is a string or an integer. You can do this with trouting as follows:

from typing import Any, Union
from trouting import trouting

class MyClass:
    @trouting
    def add_one(self, a: Any) -> Any:
        # fallback method
        raise TypeError(f"Type {type(a)} not supported")

    @add_one.add_interface(a=(int, float))
    def add_one_int(self, a: Union[int, float]) -> float:
        # a is an int or float
        return float(a + 1)

    @add_one.add_interface(a=str)
    def add_one_str(self, a: str) -> str:
        # a is a str
        return a + "1"

Now, when using MyClass, the method add_one will behave differently depending on the input type:

my_class = MyClass()
my_class.add_one(1) # returns 2.0
my_class.add_one("1") # returns "11"
my_class.add_one([1]) # raises TypeError