* Move some constants in preparation
This makes some minor changes to constants to facilitate splitting out a
stepwise interpreter.
* Extract a step function from the interpreter
This is generally useful for testing, but specifically, we want to be
able to run this side-by-side with the C++ interpreter, and check that
every bit of our state matches along the way.
This change is as minimal as possible, to avoid divergence until after
it can be compared against C++. E.g., the massive `match opcode {…}`
block that has been moved should only change the dereferencing of
`op_count`.
* Add a `State` struct to make stepping easier
* Expose step interpreter
* Add a stepwise comparison interpreter
The C++ changes aren’t in place yet, so this is currently just an A/A test.
This changes our closures into structs containing a function, because
that’s how we can pass around functions with universally-quantified
lifetimes.
* Make interpreters more flexible
Previously the `ZcashScript` impls didn’t use `self`, so the types were
just tags. However, with the new `StepwiseInterpreter`, they need
`self`.
This also removes `RustInterpreter` in favor of a `rust_interpreter`
function that instantiates an appropriate `StepwiseInterpreter`.
* Add a function for C++/Rust comparison interpreter
* Fix fuzzer
* Clean up `use` in lib.rs
* Fix weird indentation
* Make various fields non-`pub`
* Add a `new` constructor for `Stack`
* Remove incorrect comment
* Appease Clippy
Adds `Default` impls for `Stack` and `State`.
* Rename `State::manual` to `State::from_parts`
cc157ffdce