In this commit I remove all `*Gadget` types and instead implement the naming convention defined here https://github.com/0xPARC/pod2/issues/181#issuecomment-3051954321
The biggest changes can be summarized by:
- a) Removal of `*Gadget` types and their `eval_*` methods in favour of `verb_object_circuit` functions.
- b) The above functions don't create targets that need to be witness-assigned later. Instead they receive those as arguments. This clearly shows what's the circuit input and output.
I'm specially happy about the changes from b), I think they make the flow of data in the circuit more clear.
Missing things that I did not address in this PR
- The RecursiveCircuit still uses some old naming conventions like `build`.
- We have some `*Target` types that have methods that define constraints. I think we can keep those as they are convenient and I don't see them as strongly breaking the new convention: I see them as the object-oriented way to apply the convention. In those cases the `object` can be omitted from the method when it's implied by the type name, and the `_circuit` suffix doesn't appear because it's implied by the fact that the type is a `*Target`. Examples are: `SignatureTarget::verify -> BoolTarget`, `StatementTarget::has_native_type -> BoolTarget` or `OperationTypeTarget::as_custom -> (BoolTarget, HashOutTarget, Target)`.
Eduard S.
143a8c9d4e