[PSR-14] Meeting Summary - 2018-05-10

[Larry Garfield]

The latest summary from the PSR-14 Working Group:

* We had short presentations/brain dumps on Java, Node, Python, and Ruby and
what appears to be "state of the art" for event management in those
ecosystems.
* The big takeaway is that no one seems to be doing anything radically
different than the general pattern in PHP, give or take quirks of each
language. If anything, it appears PHP has a more robust event-dispatching-
mediated-observer type ecosystem than anyone else, which is rather amusing.
:-)
* Of note, Node.js, despite being a largely asynchronous environment, uses
synchronous events. It's up to each listener to kick its own body off to an
async task if appropriate. The WG is strongly considering this as a viable
approach for handling asynchronous event listeners for PSR-14.
* Both Python and Node favor "arbitrary series of function arguments" over a
defined event object. Java naturally uses a typed event object, as do most
current PHP implementations (Drupal being the notable semi-exception.) The WG
strongly favors a typed object at this point.
* Node.js also has a feature where an exception in a listener gets turned into
an "error event" automatically. This may be something to consider for PSR-14
but may also be left to implementers. TBD.
* We spent a fair bit of time chewing on the question of listener ordering.
There's a number of mechanisms in the wild in various languages and it's not
clear yet what approach would be best for us to take, or if it would be better
to punt entirely. TBD.

Next steps:

* We'll be getting brief presentations on the state of the art in C# and Go in
our next meeting to round-out the research.
* Members of the WG are working on "must have" and "nice to have" lists to
compare/defend at the next meeting.

ATTENTION PROJECT REPS: If there is something your project views as a "must
have" or "nice to have" for event dispatching, please reach out to the Editor
(me, Larry) before 24 May. I'll aggregate those and present at the next
meeting.

--Larry Garfield, PSR-14 Editor