Update IRC appender to v3 appender style

[crisptrutski]

Refers to: #41

Includes some small incidental fixes/tweaks, but maintained backwards compatibility I believe.

Non-backwards compatible changes that present themselves:

1. Replace global conn atom with one scoped/created inside make-irc-appender.
2. Replace prefix-fn pattern with fmt-output-fn usage

Also happy to add some tests (guess I'd just mock the irclj functions?)

[ptaoussanis]

Hey Chris, this looks great - thank you! Sorry for the delayed reply btw, have been travelling.

Replace global conn atom with one scoped/created inside make-irc-appender.

Sound good to me. I get the impression that the current global conn is effectively private, so don't think this should be breaking in most cases.

Replace prefix-fn pattern with fmt-output-fn usage

I think that'd be an acceptable break, but thanks for checking.

Also happy to add some tests (guess I'd just mock the irclj functions?)

If you think there's something specifically worth automated testing, otherwise wouldn't worry about it.

So I'll wait on an updated PR with the additional 2 changes? Again, much appreciated! Cheers :-)

[crisptrutski]

No worries on delay - how were the travels?

Took a stab at those extra changes, and left just a smidgeon of testability via comments.

RE: the prefix-fn business, seemed like that function was never being called, at least in my testing. Should behave along lines of original intention now (level is wrapped in [..] though). Using a fmt-output-fn option in the actual appender config to leave this configurable, not sure if that was the appropriate pattern.

Now that you're back at the helm I'll be on the look out for more places to sneak my code into your high profile libraries ;)

[crisptrutski]

Also let me know if you want these commits squashed up a bit, err'd on the side of micro incase you wanted any changes knocked out.

[ptaoussanis]

No worries on delay - how were the travels?

Oh, they were still ongoing :-) Back now, really sorry about the huge delay getting this merged - was trying to actually take a real work-free vacation for once, so no non-critical work for a few weeks :-)

Now that you're back at the helm I'll be on the look out for more places to sneak my code into your high profile libraries ;)

Sure, always happy to see good PRs like these! (I'll be a lot more responsive now btw).

Also let me know if you want these commits squashed up a bit, err'd on the side of micro incase you wanted any changes knocked out.

No, no - this is perfect, can squash from my end if I like. Merging now.

Cheers and, again, thanks!