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Yura Lazarev Unisay

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@viktorklang
viktorklang / ScalaEnum.scala
Created June 30, 2011 23:12
DIY Scala Enums (with optional exhaustiveness checking)
trait Enum { //DIY enum type
import java.util.concurrent.atomic.AtomicReference //Concurrency paranoia
type EnumVal <: Value //This is a type that needs to be found in the implementing class
private val _values = new AtomicReference(Vector[EnumVal]()) //Stores our enum values
//Adds an EnumVal to our storage, uses CCAS to make sure it's thread safe, returns the ordinal
private final def addEnumVal(newVal: EnumVal): Int = { import _values.{get, compareAndSet => CAS}
val oldVec = get
@dherman
dherman / emacs-cheat-sheet.md
Created August 2, 2012 16:22
My emacs cheat sheet

In penance for cracking stupid jokes on Twitter, here's my Emacs cheat sheet. Emacs has a steep learning curve, so I've tried to order them by importance so you could learn them in stages.

One overall rule of thumb: pay attention to the minibuffer (the line at the bottom of the editor). It will often guide you through a process, and also gives you hints about what state you're in, such as the middle of a multi-chord sequence.

The other rule of thumb: when in doubt, C-g it out.

Basics (mandatory)

You simply can't get by without having these at your fingertips.

@stephenhardy
stephenhardy / git-clearHistory
Created April 26, 2013 22:14
Steps to clear out the history of a git/github repository
-- Remove the history from
rm -rf .git
-- recreate the repos from the current content only
git init
git add .
git commit -m "Initial commit"
-- push to the github remote repos ensuring you overwrite history
git remote add origin git@github.com:<YOUR ACCOUNT>/<YOUR REPOS>.git
@martintrojer
martintrojer / exprPattern.scala
Last active July 2, 2021 06:23
expression problem
object exprPattern extends App {
sealed trait Expr
case class Add(e1: Expr, e2: Expr) extends Expr
case class Sub(e1: Expr, e2: Expr) extends Expr
case class Num(n: Int) extends Expr
def value(e: Expr): Int = e match {
case Add(e1, e2) => value(e1) + value(e2)
case Sub(e1, e2) => value(e1) - value(e2)
case Num(n) => n
@willurd
willurd / web-servers.md
Last active July 8, 2024 17:56
Big list of http static server one-liners

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000
@agemooij
agemooij / SnakifiedSprayJsonSupport.scala
Last active November 18, 2020 14:34
An example of how to customize the field mapping in spray-json to do generic transformation, in this case translating between camelcased Scala attributes and snakecase JSON attributes
/**
* The MIT License (MIT)
*
* Copyright (c) 2013-2015 Andrew Snare, Age Mooij
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
@djspiewak
djspiewak / streams-tutorial.md
Created March 22, 2015 19:55
Introduction to scalaz-stream

Introduction to scalaz-stream

Every application ever written can be viewed as some sort of transformation on data. Data can come from different sources, such as a network or a file or user input or the Large Hadron Collider. It can come from many sources all at once to be merged and aggregated in interesting ways, and it can be produced into many different output sinks, such as a network or files or graphical user interfaces. You might produce your output all at once, as a big data dump at the end of the world (right before your program shuts down), or you might produce it more incrementally. Every application fits into this model.

The scalaz-stream project is an attempt to make it easy to construct, test and scale programs that fit within this model (which is to say, everything). It does this by providing an abstraction around a "stream" of data, which is really just this notion of some number of data being sequentially pulled out of some unspecified data source. On top of this abstraction, sca

@weavenet
weavenet / delete_all_object_versions.sh
Created May 4, 2015 05:21
Delete all versions of all files in s3 versioned bucket using AWS CLI and jq.
#!/bin/bash
bucket=$1
set -e
echo "Removing all versions from $bucket"
versions=`aws s3api list-object-versions --bucket $bucket |jq '.Versions'`
markers=`aws s3api list-object-versions --bucket $bucket |jq '.DeleteMarkers'`
@Avaq
Avaq / combinators.js
Last active July 4, 2024 07:20
Common combinators in JavaScript
const I = x => x
const K = x => y => x
const A = f => x => f (x)
const T = x => f => f (x)
const W = f => x => f (x) (x)
const C = f => y => x => f (x) (y)
const B = f => g => x => f (g (x))
const S = f => g => x => f (x) (g (x))
const S_ = f => g => x => f (g (x)) (x)
const S2 = f => g => h => x => f (g (x)) (h (x))
@etorreborre
etorreborre / reader-lenses.scala
Last active March 10, 2016 16:49
Use of lenses to access only specific parts of a configuration when using the Reader monad
package application
import cats.data.Reader
import cats.data.Kleisli._
import monocle.macros.Lenses
object Application {
/**
* A general configuration for the system