Improve selectors to split a circuit network signal group

[Kystael]

TL;DR

Add an option to selector combinators to select input by group so that they can select the N first signals they receive, N being either constant or parameter.

What?

I would like to be able to split network signals in different groups, by selecting a defined count of signals given to a selector. As selecting a single signal works, it could use either a variable or a constant.

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In this example, we could set filters of an inserter with a single selector instead of a big array of combinators.

Why?

Currently, we can select a signal from a signal group using the "Select Input" mode of a selector combinator, but we can only select one using the index, leading to a big array of combinators.

In this next example I set the requests of requestor chests by group so that my train content matches the logistic group used by the constant combinator, without separating stacks of the same item type in two wagon.

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If we want to split N signals into two groups, we need more than Nx2 combinators. In order to handle a dynamic number of signals, we have to ensure that there is well enough combinators, even if at some point we want to split 4 signals into two groups. In other words, the maximum limit of signal to split is static.

Another solution to split groups currently without selector combinator, still takes as much room (still takes 2 combinators for each signal).

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Concrete use case example

I replicated most of the functionality of logistic requests to the train so that I can ask anything to a train, from anywhere, without needing 30 different trains.
Without the signal split, I would lose a significant amount of cargo space in my train. With the signal split, I lose a significant amount of room in the train station and will probably put more combinators than needed so that I can handle more signals if I decide to edit the logistic group related to that train.
Here is my creation : I lose space because some wagons split their content (so here I didn't split signals). I also didn't explain the full logic to simplify what's already complex enough.

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With ALT-mode ON :

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One of the end goals is to create a train with everything needed for outposting. Maybe in the future I will find a usage to have distant crafting spaces with separated logistic network and this will handle also this case properly (I just have to add everything needed for crafting in the logistic requests).

Anyway, I am pretty sure this change has other uses, notably to have sushi belts with dynamic content and filter inserters without too many combinators. I'm sure it would give more flexibility to set request of requestor chests in some factories with dynamic logistic input.

I think being able to read content of each wagon would also solve my specific issue, but I think improving the selector combinator would cover more use cases and could be as complex of a change.

What do you think ? Is it too niche ? Can you think of cases where you had the issue ?
I found this topic but it covered two different issues so the one I am presenting here wasn't considered as the subject : viewtopic.php?f=6&t=118104&p=627991&hil ... ut#p627991

Thank you very much for your time reading my post and for your potential response.