Add LogLevel as argument to LogFormatter

[rkallos]

RFC text

Closes #3594

[SeanTAllen]

this doesn't need String(4) etc, the constant

"FINE"

will work.

[rkallos]

I'm getting compilation errors on 0.35.1:

/home/richard/code/pony/ponyc/packages/logger/logger.pony:101:32: can't recover to this capability
  fun string(): String iso^ => recover iso "FINE" end
                               ^
    Info:
    /home/richard/code/pony/ponyc/packages/logger/logger.pony:101:44: expression type is String val
      fun string(): String iso^ => recover iso "FINE" end
                                               ^

I went with trying to return String iso^ so LogLevel implements the Stringable interface. I don't see much harm in returning String val, though.

[SeanTAllen]

This is how we currently do in the rest of the standard library:

https://playground.ponylang.io/?gist=4d72cefd46cf9a24ba5e78d4e6e597de

So let's go with that for consistency.

Here's some examples:

primitive ExecveError
  fun string(): String iso^ => "ExecveError".clone()

primitive PipeError
  fun string(): String iso^ => "PipeError".clone()

primitive ForkError
  fun string(): String iso^ => "ForkError".clone()

[rkallos]

Ah, yes. That is much nicer.

Done.

[SeanTAllen]

should the default print the log level?

[rkallos]

I'm leaning toward no. I think it violates expectations slightly by printing the log level used in create(), rather than the log level used in the boolean before logging. E.g:

let logger = StringLogger(Info, env.out)
logger(Error) and logger.log("blah") // would print "INFO: blah"

[SeanTAllen]

I'm leaning towards no as well.

[SeanTAllen]

I don't think there is much value in these test changes. I'd prefer to see them remain as they were.

[rkallos]

Removed.

[SeanTAllen]

Sweet. Thanks @rkallos. Now we can move forward with the Corral change.