nuttycom

trait A {
  // define an algebra over the known space of subtypes
  def fold[X](af: A => X, bf: B => X, cf: C => X): X
}

trait B extends A {
  def fold[X](af: A => X, bf: B => X, cf: C => X): X = bf(this)
}

arvearve

Mathematics: What do grad students in math do all day?

by Yasha Berchenko-Kogan

A lot of math grad school is reading books and papers and trying to understand what's going on. The difficulty is that reading math is not like reading a mystery thriller, and it's not even like reading a history book or a New York Times article.

The main issue is that, by the time you get to the frontiers of math, the words to describe the concepts don't really exist yet. Communicating these ideas is a bit like trying to explain a vacuum cleaner to someone who has never seen one, except you're only allowed to use words that are four letters long or shorter.

What can you say?

robinp

object stateTRunner {

  def runWhileUsing[F[+_], S, A, B](st: StateT[F, S, A])(init: S, p: S => Boolean, f: (S, A) => B)(implicit F: Monad[F]): F[List[B]] = {
    def runWhile0(st: StateT[F, S, A], init: S, accum: List[B]): F[List[B]] = {
      if (!p(init)) F.point(accum.reverse)
      else F.bind(st.run(init)) {
        case (s, a) => runWhile0(st, s, f(s, a) :: accum)
      }
    }
    runWhile0(st, init, Nil)

jamie-allen

import akka.actor._
import akka.pattern.ask
import akka.util._
import akka.util.duration._
import scala.util.control.Exception._

/**
 * To test, execute this code and use this command in a shell: "telnet localhost 8080"
 * At the prompt, type in numbers and press enter, and they will be accumulated, returning
 * the total value each time.

oxbowlakes

<?xml version="1.0" encoding="UTF-8"?>
<scheme name="OxbowSolarizedDark" version="1" parent_scheme="Default">
  <option name="LINE_SPACING" value="1.2" />
  <option name="EDITOR_FONT_SIZE" value="13" />
  <option name="EDITOR_FONT_NAME" value="Consolas" />
  <colors>
    <option name="ADDED_LINES_COLOR" value="" />
    <option name="ANNOTATIONS_COLOR" value="2b36" />
    <option name="ANNOTATIONS_MERGED_COLOR" value="" />
    <option name="CARET_COLOR" value="dc322f" />