hsavit1

import { buildSchema, graphql } from "graphql";

// Construct a schema, using GraphQL schema language
let graphqlSchema = buildSchema(`
  type Query {
    recipes: [Recipe]
    recipes_by_pk(id: Int!): Recipe
  }
  type Recipe {
    id: ID!

hsavit1

defmodule SqlParser do
  def run() do
    input = "select col1 from (
      select col2, col3 from (
        select col4, col5, col6 from some_table
      )
    )
    "
    IO.puts("input: #{inspect(input)}\n")
    IO.inspect(parse(input))

hsavit1

Keybase proof

I hereby claim:

• I am hsavit1 on github.
• I am henry_s (https://keybase.io/henry_s) on keybase.
• I have a public key ASBehtOERO0XSzcL87y6jBqgpvrxRE2XOHqBxl2LZc4Z5Qo

To claim this, I am signing this object:

hsavit1

// connect() is a function that injects Redux-related props into your component.
// You can inject data and callbacks that change that data by dispatching actions.
function connect(mapStateToProps, mapDispatchToProps) {
  // It lets us inject component as the last step so people can use it as a decorator.
  // Generally you don't need to worry about it.
  return function (WrappedComponent) {
    // It returns a component
    return class extends React.Component {
      render() {
        return (

hsavit1

If you want a run-down of the 1.3 changes and the design decisions behidn those changes, check out the LonestarElixir Phoenix 1.3 keynote: https://www.youtube.com/watch?v=tMO28ar0lW8

To use the new phx.new project generator, you can install the archive with the following command:

$ mix archive.install https://github.com/phoenixframework/archives/raw/master/phx_new.ez

Bump your phoenix dep

Phoenix v1.3.0 is a backwards compatible release with v1.2.x. To upgrade your existing 1.2.x project, simply bump your phoenix dependency in mix.exs:

hsavit1

extension Array {
    var match : (head: T, tail: [T])? {
      return (count > 0) ? (self[0],Array(self[1..<count])) : nil
    }
}

func map<A,B>(f: A -> B, arr: [A]) -> [B] {
    if let (head,tail) = arr.match {
        return [f(head)] + map(f, tail)
    } else {

hsavit1

A composable pattern for pure state machines with effects

State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?

There are existing design patterns for state machines, but all the patterns I've seen conflate side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.

Here I present a composable pattern for pure state machiness with effects,

hsavit1

defmodule Server do
  def start(callback_module, state \\ nil) do
    parent = self
    spawn fn ->
      loop(callback_module, parent, state)
    end
  end

  def loop(callback_module, parent, state) do
    receive do

hsavit1

defmodule Speaker do
  def speak do
    receive do
      {:say, msg} -> 
        IO.puts(msg)
        speak
      _other ->
        speak # throw away the message
    end
  end

hsavit1

defprotocol Functor do
  def fmap(data, func)
end

defprotocol Applicative do
  def pure(data)
  def run(wrapped_func, data)
end

defprotocol Monad do