Add mypy

[ChihChengLiang]

Fixed #114

[icemelon]

I also suggest changing the line-length to 100. I think 120 is a bit too long.

[ChihChengLiang]

@icemelon I created #117 for the line-length change. Feel free to give some reviews or comments :)

[ChihChengLiang]

Hi @han0110 @icemelon,
I have some questions about the instruction part. Not sure what do you think about them.

[ChihChengLiang]

There's no write_only_persistent, do we want to keep state_write_only_persistent?

[han0110]

No, I think we forgot to remove this in previous PR.

[ChihChengLiang]

Should the output of rlc_to_int_exact FQ?

[han0110]

Yes

[ChihChengLiang]

This task is blocked. We are constantly juggling 3 types:

• IntEnum
• FQ
• RLC

Usually, a cell in a table would be of different types. For example, a value of TxTable could be gasPrice, which is stored in RLC. A value could also be caller_address, which is an FQ.

This makes our txTable lookup outputs Union[RLC, FQ], and we later need to eliminate the type to 1 possibility, which is not Python really good at.

We keep RLC because usually, we want RLC.le_bytes for computation. But the RLC.value is what is acutally stored.

[ChihChengLiang]

close in favor of @han0110's new approach. PR would be submitted soon after recent spec PRs are merged.

[ed255]

This task is blocked. We are constantly juggling 3 types:

* IntEnum

* FQ

* RLC

Usually, a cell in a table would be of different types. For example, a value of TxTable could be gasPrice, which is stored in RLC. A value could also be caller_address, which is an FQ.

This makes our txTable lookup outputs Union[RLC, FQ], and we later need to eliminate the type to 1 possibility, which is not Python really good at.

We keep RLC because usually, we want RLC.le_bytes for computation. But the RLC.value is what is acutally stored.

This sounds like a case where duck typing is needed, and for the typing we should use something like an Interface. I've taken a look at python support for "Interfaces" and there's Protocol which allows expressing types that must implement some methods.
See https://stackoverflow.com/a/60766965 for an example, and see for the docs https://stackoverflow.com/a/60766965

So we could have something like

class Expression(Protocol):
    def value(self) -> FQ:
        ...

And have IntEnum, FQ and RLC implement the method value