Generators

CSnakes supports Python generators using the typing.Generator type annotation. The typing.Generator type annotation is used to specify a generator function that yields values of a specific type.

CSnakes will convert a Python Generator to a CLR type in the CSnakes.Runtime.Python namespace that implements the IGeneratorIterator interface.

The IGeneratorIterator implements both IEnumerable<T> and IEnumerator<T> interfaces, so you can use it in foreach loops and LINQ queries.

For example the Python function:

from typing import Generator


def example_generator(length: int) -> Generator[str, int, bool]:
    for i in range(length):
        x = yield f"Item {i}"
        if x:
            yield f"Received {x}"

    return True

Will return a IGeneratorIterator<string, long, bool>. You can use this in a C# foreach loop:

var generator = env.ExampleGenerator(5);

foreach (string item in generator)
{
    Console.WriteLine(item);
}

IGeneratorIterator also implements a Send method that allows you to send values back into the generator.

The type of .Send is the TSend type parameter of the Generator type annotation and returns TYield. In the example above, the TSend type is long, so you can send a long value back into the generator:

var generator = env.ExampleGenerator(5);
string nextValue= generator.Send(10);