Recap: January 3, 2017 Meetup

Thanks, all who rocked out at our first meetup of 2017! Member David Jones recorded tonight’s talk: look for it soon on our Youtube channel,

Thanks as always to our awesome sponsors who made tonight possible. And congrats to Dave and Meining, winners of Manning’s Elixir In Action and The Little Elixir and OTP Guidebook, respectively.

The Talk

Steve Grossi walked through some experiments with making music in Elixir: We covered:

  • Communicating with the SoX audio library from Elixir
  • Using supervised processes to play audio simultaneously
  • Relying on Elixir 1.4’s upcoming Registry module as a metronome to send messages to groups of processes
  • Building a self-correcting timing mechanism when process messages arrive later than expected

Look for a recording of the talk to be posted here once it’s ready.

Then we ended the evening with an hour of musical hacking and discussion. Some highlights:

  • Ben Falk pointed out that appending items to the end of a linked list is relatively slow on the BEAM, and suggested using a queue instead, for which he’d written a library. Check out the pull request!
  • I learned the difference between performing GenServer setup in start_link vs. init. start_link happens in the originating process, while init happens in the GenServer process. So perform any memory-intensive setup in start_link to keep the GenServer’s own memory footprint small.
  • Lucas Falk suggested using guard clauses to ensure we actually get lists when we’re expecting them. Always a good practice!

Please note that we’re switching to a bi-monthly schedule, so our next event will be on March 7, 2017! We’re looking for speakers—please let me know if you’re interested!