Rintcius Blok rintcius

create-react-native-app purescript-app; cd purescript-app
pulp init --force
pulp build
src/Main.js

var React = require("react");
var RN = require("react-native");

exports.text = function(props){

map :: (a -> b) -> f a -> f b

for example for lists []

map :: (a -> b) -> [a] -> [b]

and for Maybe

map :: (a -> b) -> Maybe a -> Maybe b

Applied Functional Programming with Scala - Notes

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

Explaining Miles's Magic

Miles Sabin recently opened a pull request fixing the infamous SI-2712. First off, this is remarkable and, if merged, will make everyone's life enormously easier. This is a bug that a lot of people hit often without even realizing it, and they just assume that either they did something wrong or the compiler is broken in some weird way. It is especially common for users of scalaz or cats.

But that's not what I wanted to write about. What I want to write about is the exact semantics of Miles's fix, because it does impose some very specific assumptions about the way that type constructors work, and understanding those assumptions is the key to getting the most of it his fix.

For starters, here is the sort of thing that SI-2712 affects:

def foo[F[_], A](fa: F[A]): String = fa.toString

"A little bit of slope makes up for a lot of y-intercept"

01/13/2012. From a lecture by Professor John Ousterhout at Stanford, class CS140

Here's today's thought for the weekend. A little bit of slope makes up for a lot of Y-intercept.

[Laughter]

Mac OS X 10.11 El Capitan

Custom recipe to get OS X 10.11 El Capitan running from scratch, setup applications and developer environment. This is very similar (and currently mostly the same) as my 10.10 Yosemite setup recipe (as found on this gist https://gist.github.com/kevinelliott/0726211d17020a6abc1f). Note that I expect this to change significantly as I install El Capitan several times.

I use this gist to keep track of the important software and steps required to have a functioning system after a semi-annual fresh install. On average, I reinstall each computer from scratch every 6 months, and I do not perform upgrades between distros.

This keeps the system performing at top speeds, clean of trojans, spyware, and ensures that I maintain good organizational practices for my content and backups. I highly recommend this.

You are encouraged to fork this and modify it to your heart's content to match your own needs.

	module Main where

	import Prelude hiding (add)
	import Control.Monad.Eff (Eff)
	import Data.Function.Uncurried
	import Data.Array
	import Data.Foreign
	import Data.List as L
	import Data.Maybe (Maybe(..))
	import Data.Tuple

	// These lines go in ~/.sbt/0.13/global.sbt
	watchSources ++= (
	(baseDirectory.value * "*.sbt").get
	++ (baseDirectory.value / "project" * "*.scala").get
	++ (baseDirectory.value / "project" * "*.sbt").get
	)

	addCommandAlias("rtu", "; reload ; test:update")
	addCommandAlias("rtc", "; reload ; test:compile")
	addCommandAlias("ru", "; reload ; update")

	% sbtx dependencyGraph
	... blah blah ...
	[info] * Welcome to the sbt build definition for Scala! *
	[info] Check README.md for more information.
	[error] Not a valid command: dependencyGraph
	[error] Not a valid project ID: dependencyGraph


	% sbtx -Dplugins=graph dependencyGraph
	... blah blah ...

	// module Hetero

	exports.mkExists = function(fa) {
	return fa;
	};

	exports.runExists = function(f) {
	return function(fa) {
	return f(fa);
	};