arturmkrtchyan

|----------------------------------------------------------------------------------------|--------------------|
|                                    Object Header (64 bits)                             |        State       |
|-------------------------------------------------------|--------------------------------|--------------------|
|                  Mark Word (32 bits)                  |      Klass Word (32 bits)      |                    |
|-------------------------------------------------------|--------------------------------|--------------------|
| identity_hashcode:25 | age:4 | biased_lock:1 | lock:2 |      OOP to metadata object    |       Normal       |
|-------------------------------------------------------|--------------------------------|--------------------|
|  thread:23 | epoch:2 | age:4 | biased_lock:1 | lock:2 |      OOP to metadata object    |       Biased       |
|-------------------------------------------------------|--------------------------------|--------------------|
|               

eevee

HEY: I've turned this into a blog post, which is a little more in depth.

🚨 https://eev.ee/blog/2016/06/04/converting-a-git-repo-from-tabs-to-spaces/ 🚨

---

Death to tabs, long live spaces

Do this

jdegoes

Applied Functional Programming with Scala - Notes

Copyright © 2016-2018 Fantasyland Institute of Learning. All rights reserved.

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

jashkenas

Spurred by recent events (https://news.ycombinator.com/item?id=8244700), this is a quick set of jotted-down thoughts about the state of "Semantic" Versioning, and why we should be fighting the good fight against it.

For a long time in the history of software, version numbers indicated the relative progress and change in a given piece of software. A major release (1.x.x) was major, a minor release (x.1.x) was minor, and a patch release was just a small patch. You could evaluate a given piece of software by name + version, and get a feeling for how far away version 2.0.1 was from version 2.8.0.

But Semantic Versioning (henceforth, SemVer), as specified at http://semver.org/, changes this to prioritize a mechanistic understanding of a codebase over a human one. Any "breaking" change to the software must be accompanied with a new major version number. It's alright for robots, but bad for us.

SemVer tries to compress a huge amount of information — the nature of the change, the percentage of users that wil

retronym

class A
class A2 extends A
class B

trait M[X]

//
// Upper Type Bound
//
def upperTypeBound[AA <: A](x: AA): A = x

lg0

<!-- copy this to YOUR_THEME.tmTheme-->
  <dict>
	    <key>name</key>
	    <string>diff: deleted</string>
	    <key>scope</key>
	    <string>markup.deleted</string>
	    <key>settings</key>
	    <dict>
	        <key>background</key>
	        <string>#EAE3CA</string>

milessabin

scala> import shapeless._, syntax.singleton._, record._
import shapeless._
import syntax.singleton._
import record._

scala> object ->> {
     |   def unapply[K, V](f: FieldType[K, V])(implicit k: Witness.Aux[K]) = Option((k.value, f: V))
     | }
defined module $minus$greater$greater

brendanzab

A graph-based core for a dependently typed language

Abstract

An overly-ambitious attempt to re-think the core calculus of dependent type theory by basing it on graphs as opposed to lambdas, Π-types, Σ-types, etc. The hope is that this might allow us to investigate dependency more closely, and allow us to refine programs to target different environments in an easier way than with traditional programming representations.

Introduction

pchiusano

/** GADTs in Scala and their limitations */

/** Background: what is an algebraic data type (ADT) ? 
  * ADT: (possibly) recursive datatype with sums and products
  * In scala - a trait with case classes (case class is product, subtyping is sum) 
  */

/** Motivation: untyped embedded DSL doesn't prevent nonsensical expressions */
sealed trait Expr { 
  def apply(other: Expr) = Ap(this, other)

scotu

.highlight { background-color: #ffffcc }
.highlight .c { color: #586E75 } /* Comment */
.highlight .err { color: #93A1A1 } /* Error */
.highlight .g { color: #93A1A1 } /* Generic */
.highlight .k { color: #859900 } /* Keyword */
.highlight .l { color: #93A1A1 } /* Literal */
.highlight .n { color: #93A1A1 } /* Name */
.highlight .o { color: #859900 } /* Operator */
.highlight .x { color: #CB4B16 } /* Other */
.highlight .p { color: #93A1A1 } /* Punctuation */