SystemFw

Balaji Sivaraman @balajisivaraman_twitter

Hi all, I need some help understanding a piece of Doobie code from the examples. It is the StreamingCopy one: (https://github.com/tpolecat/doobie/blob/series/0.4.x/yax/example/src/main/scala/example/StreamingCopy.scala). I am using a modified version of the fuseMap2 example from that file. Here’s how I’ve modified it for my requirements:

  def fuseMap[F[_]: Catchable: Monad, A, B](
      source: Process[ConnectionIO, A],
      sink: Vector[A] => ConnectionIO[B],
      delete: ConnectionIO[Unit]
  )(
 sourceXA: Transactor[F],

marcelog

{
  "Version": "2012-10-17",
  "Id": "arn:aws:sqs:YOUR-AWS-REGION:YOUR-AWS-ACCOUNT-ID:YOUR-QUEUE-NAME/SQSDefaultPolicy",
  "Statement": [
    {
      "Sid": "example-statement-ID",
      "Effect": "Allow",
      "Principal": {
        "AWS": "*"
      },

eed3si9n

lazy val root = (project in file(".")).
  settings(
    scalaVersion := "2.11.8",
    // libraryDependencies += "org.scala-lang.modules" %% "scala-xml" % "1.0.4",
    dependencyOverrides += "org.scala-lang.modules" %% "scala-xml" % "1.0.5"
  )

djspiewak

Explaining Miles's Magic

Miles Sabin recently opened a pull request fixing the infamous SI-2712. First off, this is remarkable and, if merged, will make everyone's life enormously easier. This is a bug that a lot of people hit often without even realizing it, and they just assume that either they did something wrong or the compiler is broken in some weird way. It is especially common for users of scalaz or cats.

But that's not what I wanted to write about. What I want to write about is the exact semantics of Miles's fix, because it does impose some very specific assumptions about the way that type constructors work, and understanding those assumptions is the key to getting the most of it his fix.

For starters, here is the sort of thing that SI-2712 affects:

def foo[F[_], A](fa: F[A]): String = fa.toString

UnkindPartition

#!/usr/bin/perl

# (c) Roman Cheplyaka, 2016
# License: MIT

# Usage:
#
# combined_to_csv FILE1 FILE2 ... > FILE.csv
#
# The resulting CSV file can be read in R with:

bishboria

These links no longer work. Springer have pulled the free plug.

Graduate texts in mathematics

duplicates = multiple editions

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

A Classical Introduction to Modern Number Theory, Kenneth Ireland Michael Rosen

dwijnand

+-----------------------------------------------------------------------------------------------------+
|  name   |  bits  | bytes  |  min  | actual min value           |  max   | actual max value          |
|---------+--------+--------+-------+----------------------------+--------+---------------------------|
| boolean |  1-bit |   --   | false |                            | true   |                           |
| byte    |  8-bit | 1-byte | -2^7  | -128                       | 2^7-1  | 127                       |
| short   | 16-bit | 2-byte | -2^15 | -32'768                    | 2^15-1 | 32'767                    |
| char    | 16-bit | 2-byte | 0     | '\u0000'                   | 2^16-1 | '\uffff'  (65535)         |
| int     | 32-bit | 4-byte | -2^31 | -2'147'483'648             | 2^31-1 | 2'147'483'647             |
| long    | 64-bit | 8-byte | -2^63 | -9'223'372'036'854'775'808 | 2^63-1 | 9'223'372'036'854'775'807 |
| float   | 32-bit | 4-byte | +/- -3.4028235 * 10^38             | +/- 3.4028235 * 10^38

djspiewak

Collections Redesign Proposal

I'm going to start off by motivating what I'm doing here. And I want to be clear that I'm not "dissing" the existing collections implementation or anything as unproductively negative as that. It was a really good experiment, it was a huge step forward given what we knew back in 2.8, but now it's time to learn from that experiment and do better. This proposal uses what I believe are the lessons we can learn about what worked, what didn't work, and what is and isn't important about collections in Scala.

This is going to start out sounding really negative and pervasively dismissive, but bear with me! There's a point to all my ranting. I want to be really clear about my motivations for the proposal being the way that it is.

Problems

Generic Interfaces

tpolecat

EDIT: This gist has been promoted and is now a blog post.

Kinda-Curried Type Parameters

Scala methods can have multiple lists of value parameters but only one list of type parameters, which is occasionally irritating when some are inferable and others are not. Consider this method which has two type parameters, one inferable and one not.

import scalaz._, Scalaz._

propensive

Welcome to Scala version 2.10.5 (OpenJDK 64-Bit Server VM, Java 1.6.0_27).
Type in expressions to have them evaluated.
Type :help for more information.

// We're using returnResult mode, so that methods return `Result`s instead of throwing exceptions
scala> import rapture.core._, modes.returnResult._
import rapture.core._
import modes.returnResult._

// Our LaTeX backend of choice is xelatex