Document custom gates

[xevisalle]

Summary

Atm, the documentation includes how custom gates are used at the Plonk protocol level. However, how the specific custom gates are constructed is still something TBC. We should document them.

[Crisis82]

Any progress with the custom gates documentation?
I'm using your library in a personal project and I would like to implement my own generic power custom gate, but I'm stuck trying to find the documentation.

[xevisalle]

Any progress with the custom gates documentation? I'm using your library in a personal project and I would like to implement my own generic power custom gate, but I'm stuck trying to find the documentation.

thank you for your interest in our library! Unfortunately, we are prioritizing other tasks at the moment. Nevertheless, the specs include how the arithmetic gate is implemented, and where the other custom ones are placed in the protocol. Hopefully with this and the code, you can apply your changes.