smarter

Generalized Algebraic Data Types in Scala

Basic GADTs

Here's an ADT which is not a GADT, in Haskell:

data Expr = IntExpr Int | BoolExpr Bool

OlivierBlanvillain

import shapeless.{HList, HNil, ::}
import shapeless.ops.hlist.{Selector, Prepend}
import shapeless.test.illTyped

object TypeLevelBacktrack extends App {
  /** [[Parent]] / [[Child]] relationship, father side. */
  trait FatherOf[Parent, Child]

  /** [[Parent]] / [[Child]] relationship, mother side */
  trait MotherOf[Parent, Child]

queertypes

{-# LANGUAGE FlexibleContexts, DeriveFunctor #-}
--------------------------------------------------------------------------------
-- It's no secret - Allele Dev enjoys writing Haskell
--
-- This is a tiny example of using Free monads + improve.
--------------------------------------------------------------------------------
module Control.Teletype where

import Control.Monad
import Control.Monad.Free

vt0r

GnuPG 2.2.x Build Instructions

Below are my build instructions for GnuPG 2.2.10, released on August 30th, 2018. These instructions are built for a headless Ubuntu 18.04 LTS server (and have also been tested on Ubuntu 14.04/16.04).

If you prefer, you may use the below install script to install GnuPG 2.2.x by running the following commands:

curl -OL "https://gist.githubusercontent.com/vt0r/a2f8c0bcb1400131ff51/raw/e0d2011d7b89bfe5b83c3f29f21949fb21354dd9/install-gnupg22.sh" && sudo -H bash ./install-gnupg22.sh

Install the needed dependencies

retronym

indylambda: Putting invokedynamic to work for Scala

Java 8 introduced lambdas to the Java language. While the design choices differ in many regards from Scala's functions, the underlying mechanics used to represent Java lambdas is flexible enough to be used as a target for the Scala compiler.

Lambdas in Java

Java does not have canonical heirarchy of generic function types (ala scala.FunctionN), but instead allows a lambda to be used as a shorthand for an anonymous implementation of an Functional Interface

Here's an example of creating a predicate that closes over one value:

colestanfield

// Create a new MergeStrategy for aop.xml files
val aopMerge: MergeStrategy = new MergeStrategy {
  val name = "aopMerge"
  import scala.xml._
  import scala.xml.dtd._

  def apply(tempDir: File, path: String, files: Seq[File]): Either[String, Seq[(File, String)]] = {
    val dt = DocType("aspectj", PublicID("-//AspectJ//DTD//EN", "http://www.eclipse.org/aspectj/dtd/aspectj.dtd"), Nil)
    val file = MergeStrategy.createMergeTarget(tempDir, path)

tstone

implicit class StringOps(s: String) {
  
  val one = { println("one"); "one" }
  val two = { println("two"); "two" }
  lazy val three = { println("three"); "value" }

}

scala> "asdf".three
one

ashrithr

#!/bin/bash

function usage () {
script=$0
cat <<USAGE
Creates scala project structure to be used with sbt

Syntax
`basename $script` project_name artifact_id