Call for speakers for PS Unscripted May 2018


Has anyone learned a useful PS concept or library recently? Tried to use PS to solve a common app design problem? You should share your knowledge at the PS Unscripted meetup.

Topics likely to appear this time:

  • Demo(s) of some things enabled by the PureScript 0.12 release.
  • Detecting equality of functions and simulating GADTs in PureScript, motivated by implementing JSON decoders.


I’ve been doing some work on purescript-elm again lately, after a long hiatus. (It’s a work-in-progress to translate the Elm framework into Purescript).

There are a few things I could talk about sometime:

  • What the Elm 0.18 version of the Elm Architecture looks like in a Purescript implementation (the model-update-view triplet, and Elm’s effect managers)

  • Strategies to use when you really want to detect the equality of functions (despite it being impossible).

  • Simulating GADTs in Purescript using Leibniz equality and Rank-N functions. (There are some good blog posts on this, but it’s nice to see examples – it’s not the easiest thing to wrap your head around).


I have a few experimental UI-related libraries that I could talk about:

  • purescript-sdom
  • purescript-incremental and purescript-purview
  • purescript-react-explore and purescript-smash


I could also talk about some fun 0.12-enabled stuff (e.g.


I think this month’s gathering is a good time to talk about the 0.12 release, so I’d like to have @justinw talk about some 0.12 stuff.

@paf31, you’ve mentioned being able to talk about some of your lib at past gatherings, but your time has always been short. If you’re available for this month’s meetup, I think you have priority in the queue. :slight_smile:


Actually, I’d prefer to do next month if @justinw can do this one. I’m already preparing a talk on react-explore at the moment, so I can either reuse that one, or prepare something else.


@paf31 Sure, then if you’re interested, @rgrempel, there’s likely also time for one of your topics at this month’s.


OK, I think it would be easiest for me to focus on the work I’ve done recently on translating Elm’s approach to JSON decoders into Purescript. That will touch on topics 2 and 3 – what to do when you want equality checking for functions (despite it being impossible), and simulating GADTs in Purescript using Leibniz equality.

That will be quicker for me to prepare than topic 1 – perhaps I can do that one in the future sometime.


@rgrempel That sounds fascinating! I hope you can make it!

Unrelated - I’d like to move the gathering’s content planning from that word doc to gathering here. I’ll just make a new thread for each month’s. I’ll do that now - I’ll link from that gathering to here. :slight_smile:


Sounds good, I’ll plan on it. How much time should I be thinking of? Perhaps 30 minutes?


Yeah, 30 minutes is good. :+1: I’d expect several minutes of discussion/questions during/after.


I uploaded and added timings to this month’s PS Unscripted video:

It was nice to hype the 0.12rc of the compiler – thanks for showing what’s possible @justinw!
It was really awesome to see how much of GADTs we can simulate in PureScript! So great to see a concrete example of Coyoneda I can reference! Thanks so much @rgrempel!