Joshua T Kalis he/him/his

Lambda Jam 2014


Transit (format)

"Transit is a format and set of libraries for conveying values between applications written in different programming languages." - http://blog.cognitect.com/blog/2014/7/22/transit


JSON Deficits


Transit Goals

  1. Schema-less (self-describing "at the bottom")
  2. Extensible
  3. Performant
  4. Reach the browser


Reactive Programming

Let the data flow.


Reactive - Traits/Goals


Responsive + Event-driven

a = b + c

Imperative - Statically assign the result of the computation on the right to the identifier on the left.

When b or c change, a will not change.

Reactive - Create a relationship between the identifier on the left and the computation on the right.

When b or c change, a will re-evaluate.


Reactive - Notes


Interactive vs. Reactive

Interactive - Programs respond at the speed of the interactions.

Reactive - Programs respond at the speed of the environment.


Design and Architecture for Actors

System design for process-based concurrency


Synonyms

Actor === Agent === Process


Process-based Concurrency Mantra

  1. Processes are not threads.
  2. Processes are really cheap.
  3. Goto 1.

Supervision Hierarchy Map

Imagine a soda vending machine; this might be a - over-simplified - diagram of its actors.

    +------------+
    |   System   |
    | Supervisor |
    +------------+
      /        \
     /          \
+---------+ +------------+
| Cooling | |  Vending   |
| System  | | Supervisor |
+---------+ +------------+
              /        \
             /          \
       +-----------+ +----------+
       | Selection | |   Soda   |
       |  Handler  | | Fetching |
       +-----------+ +----------+

Let it Crash


"Did you try and turn it off and back on again?"


No Joke

Return to a known "good" state of a system.


Random Stuff


"... debugging ... is a powerful exercise in the learning process." - Gerald Jay Sussman


"Because, physics." - Erik Meijer