emhoracek

;;; Personal configuration -*- lexical-binding: t -*-

;; Save the contents of this file under ~/.emacs.d/init.el
;; Do not forget to use Emacs' built-in help system:
;; Use C-h C-h to get an overview of all help commands.  All you
;; need to know about Emacs (what commands exist, what functions do,
;; what variables specify), the help system can provide.

;; Add the NonGNU ELPA package archive
(require 'package)

emhoracek

<h2>The Basics</h2>
<div class="basics">
  <label>
    <span>Character name: </span>
    <input spellcheck="false" type="text" name="attr_character_name"/>
  </label>
  <label>
    <span>Pronouns: </span>
    <input spellcheck="false" type="text" name="attr_pronouns"/>

emhoracek

On NOT Using PostgreSQL Advisory Locks in Haskell

Recently two different administrative users of a Haskell app I maintain started a long-running background job at the same time. This resulted in some Bad Things happening which I would like to prevent in the future!

So I want a lock. This app runs on at least two servers at any given time, so it needs to be a distributed lock, and for Reasons (not relevant to this blogpost) I can't use our Redis cache. So the PostgreSQL database it is!

emhoracek

{-

After feeling like you've been falling for a few minutes, you look at the device's tiny screen. 
"Error: Device must be calibrated before first use. Frequency drift detected. Cannot maintain
destination lock." Below the message, the device shows a sequence of changes in frequency 
(your puzzle input). A value like +6 means the current frequency increases by 6; a value like 
-3 means the current frequency decreases by 3.

For example, if the device displays frequency changes of +1, -2, +3, +1, then starting from 
a frequency of zero, the following changes would occur:

emhoracek

Using PostgreSQL Advisory Locks in Haskell

Recently two different administrative users of a Haskell app I maintain started a long-running background job at the same time. This resulted in some Bad Things happening which I would like to prevent in the future!

So I want a lock. This app runs on at least two servers at any given time, so it needs to be a distributed lock, and for Reasons (not relevant to this blogpost) I can't use our Redis cache. So the PostgreSQL database it is!

emhoracek

Magazine
  create_issue -> Draft
  Subscriber
    Subscribed
      cancel -> Lapsed
      renew -> Subscribed
    Lapsed
      renew -> Subscribed
    Subscriber?
      subscribed -> LastIssue?

emhoracek

class Order < Struct.new(:line_items, :discount_name)
  def discount
    DiscountDatabase.find_by_name(discount_name)
  end

  def discounted_line_item_prices
    line_items.map do |li|
      li.discounted_total(discount)
    end
  end

emhoracek

{
  "objs": [
    {
      "cells": [
        {
          "palette": 0,
          "offset": {
            "x": 0,
            "y": 0
          },

emhoracek

module Perceptron where

import Prelude hiding (and)

data Perceptron =
  Perceptron { inputs :: [Input]
             , bias :: Int } deriving (Eq, Show)

data Input = Input { value :: Bool
                   , weight :: Int } deriving (Eq, Show)

emhoracek

Keybase proof

I hereby claim:

• I am emhoracek on github.
• I am horrorcheck (https://keybase.io/horrorcheck) on keybase.
• I have a public key whose fingerprint is 8453 9205 8D53 6218 B02B C890 946A 8DC3 D3D7 A323

To claim this, I am signing this object: