oxbowlakes

/**
 * Part Zero : 10:15 Saturday Night
 *
 * (In which we will see how to let the type system help you handle failure)...
 *
 * First let's define a domain. (All the following requires scala 2.9.x and scalaz 6.0)
 */

import scalaz._
import Scalaz._

ms-tg

/**
 * Without worrying about concurrency, we can simply cache the return value,
 *   using null to indicate that it has not yet been calculated...
 */
public class Memoize1 extends Original {
    private Integer total;    

    @Override 
    public int total() {
        if (total == null) { 

jeffreyolchovy

import scala.math.{BigInt, BigDecimal}

object RecursiveStreams
{
  // natural numbers
  lazy val N: Stream[BigInt] = Stream.cons(BigInt(1), N.map(_ + 1))

  // fibonacci series
  lazy val fib: Stream[BigInt] = Stream.cons(BigInt(0), Stream.cons(BigInt(1), fib.zip(fib.tail).map(a => a._1 + a._2)))

phette23

# put this in your .bash_profile
if [ $ITERM_SESSION_ID ]; then
  export PROMPT_COMMAND='echo -ne "\033];${PWD##*/}\007"; ':"$PROMPT_COMMAND";
fi

# Piece-by-Piece Explanation:
# the if condition makes sure we only screw with $PROMPT_COMMAND if we're in an iTerm environment
# iTerm happens to give each session a unique $ITERM_SESSION_ID we can use, $ITERM_PROFILE is an option too
# the $PROMPT_COMMAND environment variable is executed every time a command is run
# see: ss64.com/bash/syntax-prompt.html

rgs

Falsehoods programmers believe about prices

1. You can store a price in a floating point variable.
2. All currencies are subdivided in 1/100th units (like US dollar/cents, euro/eurocents etc.).
3. All currencies are subdivided in decimal units (like dinar/fils)
4. All currencies currently in circulation are subdivided in decimal units. (to exclude shillings, pennies) (counter-example: MGA)
5. All currencies are subdivided. (counter-examples: KRW, COP, JPY... Or subdivisions can be deprecated.)
6. Prices can't have more precision than the smaller sub-unit of the currency. (e.g. gas prices)
7. For any currency you can have a price of 1. (ZWL)
8. Every country has its own currency. (EUR is the best example, but also Franc CFA, etc.)

pchiusano

This is material to go along with a 2014 Boston Haskell talk.

We are going to look at a series of type signatures in Haskell and explore how parametricity (or lack thereof) lets us constrain what a function is allowed to do.

Let's start with a decidedly non-generic function signature. What are the possible implementations of this function which typecheck?

wrangle :: Int -> Int

estliberitas

'use strict';

// Usage
//   node check-markdown-links.js path/to/markdown/file.md

// What it does:
// - Warns when `[ref][]` or `[title][ref]` style links don't have references defined on a page
// - Warns when `[ref]: URL` reference is not used anywhere
// - Warns when two `[ref]: URL` references point to same `URL`
// - Warns when `[ref]: URL` reference is defined in non-lexical order

developmentalmadness

package com.dvMENTALmadness

import akka.actor.ActorSystem
import akka.stream.ActorMaterializer
import akka.http.scaladsl.Http
import akka.http.scaladsl.model._
import scala.concurrent.Await
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.duration._

junegunn

# GIT heart FZF
# -------------

is_in_git_repo() {
  git rev-parse HEAD > /dev/null 2>&1
}

fzf-down() {
  fzf --height 50% --min-height 20 --border --bind ctrl-/:toggle-preview "$@"
}

kritzcreek

Kinds

In PureScript there are types of different kinds. Kinds are types for types. For example Int has kind Type, and we write it as Int :: Type. You can ask for the kind of a type in purs psci

> :k Int
Type

Type constructors take types to other types. For example Array (which still needs another type to form a type a value could have, like Array Int):