Event Type Declaration / Logging about vyper

[DavidKnott]

@fubuloubu Here's the format I'm currently implementing for event logging.

 MyLog: __log__({arg1: num, arg2: indexed(address)})

def example():
    MyLog(1, 0x1d805bC00b8fa3c96aE6C8FA97B2FD24B19a9801)

[fubuloubu]

Does the inside of the log need to be a structure?

[DavidKnott]

I'd prefer it not being a structure but this :

  MyLog: __log__(arg1: num, arg2: indexed(address))

Isn't valid python3.6 syntax.

[fubuloubu]

Hmm, I guess that makes sense. It's norither a function call not a structure, so it wouldn't parse

Two questions:

1. Is __log__ a Python object/function?
2. Does MyLog name get represented in the output Bytecode (for searching purposes), or is it more of a type declaration e.g. this log call matches these types?

[DavidKnott]

1. No, __log__ is just a clear way to differentiate events from globals in contracts.
2. MyLog is for type declaration (to be called later) though it will be used for searching in that it will be included in the keccak which will be used to create the event_id in the topics (topics are the part of an event that can be searched for).

[fubuloubu]

Can it be a type then? e.g. MyLog: log({arg1: num, arg2: indexed(address)})

Actually, I'm using it more like public here... Could it work like public? (And create the right logger function behind the scenes?)

Further, if set as a type like that, you could set individual entries e.g. self.MyLog.arg1 = foo and self.MyLog.arg2 = bar and have it commit after all entries are set in a given contract method? (e.g. write at the end of the method)

Random thoughts...

[DavidKnott]

MyLog: log({arg1: num, arg2: indexed(address)}) works, though I think using log instead of __log__ could make it harder to read as __log__ is more obvious.

We could make it so that individual entries can be set, though I don't think we should because then someone reading the code will have to do more work to figure out what's being logged.

I think both your ideas would improve writability at the detriment to readabi

[JackieXu]

I also prefer __log__ over log. It looks a bit out of place, but that further accentuates the difference, giving the reader feedback that it's something to look at.

I spent a bit trying to see if the syntax used by Python's typing module would work (e.g. MyLog: Log[num, indexed[address]]), but that looks a bit strange.

[DavidKnott]

@JackieXu MyLog: Log[num, indexed[address]] I like this syntax, the issue is that it doesn't allow for the event inputs to be named which is important for readability.

[DavidKnott]

Closing this issue now that the functionality has been added.

[fubuloubu]

Nice! That's a major one!