Experimental repo to run Rusts itertools in Python.

Initially, this will be mostly used as a proof of concept. This is to investigate the comparisons between:

• rust's itertools functionality vs python's itertools functionality
• rust's itertools functionality vs more_itertools functionality
• new rust functions vs more_itertools functionality
• new rust functions vs new python functions around itertools

Practically, this means not all functionality from rust's itertools will be available

Often, the major goal of porting Rust functionality over to Python is for speed. So far, my initial experimentation has shown that that gain is very low (or even non-existant) due to 2 main reasons:

• itertools is mostly written in C so already quite fast and roughly on par with Rust
• even for more_itertools and new python functions: not having to copy over the results back to Python is a major gain vs the rust implementations for the type of functions we deal with here. Example: there are over 36 million permutations of the numbers 0 to 9 (incl 9). Generating in Rust and then accessing from Python takes 2.24 seconds on my pc, where the CPython itertools takes 0.557 seconds to do the same.

There are some exceptions though, especially for:

• newly written Python code that is not in CPython (both more_itertools and additional functions in this repo)
• situations where the Rust compiler can work wonders in reducing logic down to more direct logic
• some tools for which the ratio of compute vs iteration is not as much towards iteration

Next to this, you can use this repository for functionality not available in Python's itertools or if you prefer the way the Rust version is setup.

The Github Actions setup to automatically crossbuild Python packages across operating systems has been based on the setup in the rtoml project (although first using the old setuptools based setup, because of the link on the setuptools-rust page..).

Of course, also credit to the Rust itertools project and inspiration from the more-itertools and of course the core Python itertools projects.

• Add support for all functionality of any of the itertools packages
• Make both a tuple and a list version of each method where applicable
• Make an iterable PyClass (see https://pyo3.rs/v0.22.3/class/protocols#iterable-objects) that can be reused