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@pchiusano
pchiusano / GADTs.scala
Created November 16, 2011 04:30
GADT support in Scala
/** 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)
@nifl
nifl / grok_vi.mdown
Created August 29, 2011 17:23
Your problem with Vim is that you don't grok vi.

Answer by Jim Dennis on Stack Overflow question http://stackoverflow.com/questions/1218390/what-is-your-most-productive-shortcut-with-vim/1220118#1220118

Your problem with Vim is that you don't grok vi.

You mention cutting with yy and complain that you almost never want to cut whole lines. In fact programmers, editing source code, very often want to work on whole lines, ranges of lines and blocks of code. However, yy is only one of many way to yank text into the anonymous copy buffer (or "register" as it's called in vi).

The "Zen" of vi is that you're speaking a language. The initial y is a verb. The statement yy is a simple statement which is, essentially, an abbreviation for 0 y$:

0 go to the beginning of this line. y yank from here (up to where?)

@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