| C:\projects>git clone https://[email protected]/scalaz/scalaz.git | |
| Initialized empty Git repository in C:/projects/scalaz/.git/ | |
| Password: | |
| * Couldn't find host github.com in the _netrc file; using defaults | |
| * About to connect() to proxy corp-55w-proxy.mhc port 8080 (#0) | |
| * Trying 152.159.23.21... * Connected to corp-55w-proxy.mhc (152.159.23.21) port 8080 (#0) | |
| * Establish HTTP proxy tunnel to github.com:443 | |
| * Proxy auth using Basic with user 'blahblah' | |
| > CONNECT github.com:443 HTTP/1.1 | |
| Host: github.com:443 |
| package combinatorsdemo | |
| import scala.util.parsing.combinator.RegexParsers | |
| import scala.util.parsing.input._ | |
| import scala.util.matching.Regex | |
| // type Parser[A] = List[T] => M[(A,List[T])] | |
| // parser to recognize a single token | |
| // parser that always succeeds without consuming input - constant parser | |
| // parser that always fails without consuming input |
| package xmlcombinators | |
| import scala.util.parsing.combinator.Parsers | |
| import scala.util.parsing.input.{NoPosition, Reader} | |
| import javax.xml.stream.events.{Attribute, EndElement, XMLEvent} | |
| import javax.xml.stream.{XMLEventReader, XMLInputFactory} | |
| import collection.mutable.ArrayBuffer | |
| import java.io.File | |
| /** |
| {-#LANGUAGE ExistentialQuantification, Rank2Types #-} | |
| -- using free monad for observable sharing | |
| data Free f a = Pure a | Free (f (Free f a)) | |
| data RemoteF a = | |
| N Int | |
| | Ref Int | |
| | Ap a a |
| /** 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) |
I was curious about the results reported here, which reports that Scala's mutable maps are slower than Java's: http://www.infoq.com/news/2011/11/yammer-scala
In my tests, Scala's OpenHashMap equals or beats java's HashMap:
Insertion 100k elements (String keys) time in ms:
| {-# LANGUAGE Rank2Types, ImplicitParams #-} | |
| import Control.Monad.Reader | |
| import Control.Monad.Trans | |
| -- Skip nodes let us do filtering without lookahead | |
| -- uncons is then a simple loop that removes any Skip nodes | |
| data Step a s = Empty | Yield a s | Skip s | |
| newtype ListT f a = ListT { runListT :: f (Step a (ListT f a)) } |
| object ProjectBuild extends Build { | |
| val pname = "ark" | |
| lazy val project = Project ( | |
| pname, | |
| file ("."), | |
| settings = Defaults.defaultSettings ++ List( | |
| name := pname, | |
| organization := "org." + pname, | |
| version := "0.1", | |
| // logLevel in publishLocal := Level.Debug |
| // simplest thing | |
| trait ViewImpl { | |
| def de(items: List[OBItem]): Omnibox[OBItem] | |
| } | |
| // if you want a tighter bound on the result than OBItem, like if all the elements of the list are of type SomeItem, and you want the result to also be of type Omnibox[SomeItem] | |
| trait ViewImpl { | |
| def de[OB <: OBItem](items: List[OB]): Omnibox[OB] | |
| } |
| {-# Language GADTs, Rank2Types #-} | |
| module Server where | |
| data Server li lo ri ro where | |
| Request :: lo a -> (forall b . li b -> Server li lo ri ro) -> Server li lo ri ro | |
| Respond :: ro a -> (forall b . ri b -> Server li lo ri ro) -> Server li lo ri ro | |
| Stop :: Server li lo ri ro | |
| (|>) :: Server li lo ri ro -> Server ro ri ri2 ro2 -> Server li lo ri2 ro2 |