Transformers With Generic Types

Currently, Gloe doesn’t support the creation of transformers with generic types using the @transformer or any other decorator. However, you can still create transformers with generic types by using the Transformer class directly. Some examples are provided in the gloe.collection package.

Creating the “Zip” Transformer

Suppose we want to build a transformer that receives two lists with the same length and we want to zip them.

The input type of the transformer is a tuple with two lists of the different types: list1 with type list[T] and list2 with type list[S]. So, the input type of the Zip transformer is tuple[list[T], list[U]]

The output type is a list of tuples, each tuple with type tuple[T, S]. So, the output type of the Zip transformer is list[tuple[T, S]].

Lets implement the Zip transformer using the Transformer class directly:

from typing import TypeVar, Generic
from gloe import Transformer

T = TypeVar("T")
U = TypeVar("U")

class Zip(Generic[T, U], Transformer[tuple[list[T], list[U]], list[tuple[T, U]]]):
    def transform(self, data: tuple[list[T], list[U]]) -> list[tuple[T, U]]:
        list1, list2 = data
        return list(zip(list1, list2))


For more information about the Transformer class, check gloe.Transformer.

With this class, we can use each in different types of lists:

list1 = [1, 2, 3]
list2 = ["a", "b", "c"]

zip_transformer = Zip[int, str]()

output = zip_transformer(list1, list2)
print(output)  # [(1, 'a'), (2, 'b'), (3, 'c')]