palladin

#time
#r "bin/Release/Streams.Core.dll"

open Nessos.Streams.Core
let rnd = new System.Random()
let data = [|1..10000000|] |> Array.map (fun _ -> int64 <| rnd.Next(1000000))

#r "../../packages/FSharp.Collections.ParallelSeq.1.0/lib/net40/FSharp.Collections.ParallelSeq.dll"
open FSharp.Collections.ParallelSeq

mattwarren

using NodaTime;
using System;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;

namespace JITterOptimisations
{
    public static class Extensions

raichoo

{-# OPTIONS --copatterns #-}
module Test where

open import Data.Nat
open import Data.Bool
open import Data.Vec hiding (map; head; tail; take)

record Functor (F : Set → Set) : Set₁ where
  field
    map : ∀ {A B} → (A → B) → F A → F B

palladin

type Stream<'T> = ('T -> unit) -> unit -> bool


let inline ofArray (source : 'T []) : Stream<'T> =
    fun iterf ->
        let i = ref 0
        fun () -> 
            let flag = !i < source.Length
            if not flag then
                false

OlivierBlanvillain

Revisiting Tagless Final Interpreters

Tageless Final interpreters are an alternative to the traditional Algebraic Data Type (and generalized ADT) based implementation of the interpreter pattern. This document presents the Tageless Final approach with Scala, and shows how Dotty with it's recently added implicits functions makes the approach even more appealing. All examples are direct translations of their Haskell version presented in the Typed Tagless Final Interpreters: Lecture Notes (section 2).

The interpreter pattern has recently received a lot of attention in the Scala community. A lot of efforts have been invested in trying to address the biggest shortcomings of ADT/GADT based solutions: extensibility. One can first look at cats' Inject typeclass for an implementation of [Data Type à la Carte](http://www.cs.ru.nl/~W.Swierstra/Publications/DataTypesA

nicolasstucki

Phantom types

Phantom types are designed to support compile time type evidences without any overhead costs to runtime. Phantom evidences are usually in the form of implicit arguments, which once resolved, can be erased by the compiler.

Because of these properties, phantom types are completely outside of the normal type lattice, and as such these phantom types do not inherit the semantics of Any.

odersky

Principled Meta Programming for Scala

This note outlines a principled way to meta-programming in Scala. It tries to combine the best ideas from LMS and Scala macros in a minimalistic design.

• LMS: Types matter. Inputs, outputs and transformations should all be statically typed.

• Macros: Quotations are ultimately more easy to deal with than implicit-based type-lifting

• LMS: Some of the most interesting and powerful applications of meta-programming