Return a value from with

[emilk]

Thanks for a very cool library! I hope it is OK that I come with an unsolicited PR.

I changed the entry with function to return the value of the FnOnce it encapsulates. This is an ergonomic win as it allows us to return a value from a with-scope like so:

let nd_array = autograd::with(|g| {
    let tensor = ...
    tensor.eval(&[])
});

I demonstrate its use in fn test_deconv.

[emilk]

crate::with::<f32, _> no longer compiles (this PR introduces a slight breaking change), so this either needed to be changed to crate::with::<f32, _, _>, or changed to take an explicit argument (and I chose the latter).

[raskr]

Thank you for your proposal!

This is an ergonomic win as it allows us to return a value from a with-scope

Yes I think so too, but as you mentioned, this is a breaking change. How about introducing it as a new function (e.g. ag::run) during v1.x ?

[emilk]

A new run method had been added, keeping the old with as it were. Would you like me to update all examples to use the new run instead, or should we hold off on that for a bit?

[raskr]

@emilk Thank you for the fix!

Would you like me to update all examples to use the new run instead, or should we hold off on that for a bit?

I choose the latter to avoid confusion, and I think the doc of with is explaining about the new function well enough 👍