Terkwood

# Controller option 1, implicit render selected based on format
defmodule MyApp.UserController do
  use Phoenix.Controller
  
  def show(conn, %{"id" => id}) do
    render conn, :show, user: Repo.get(User, id)
  end
end

# Controller option 2, explicit render with format pattern match

Terkwood

Elixir installation guide

Version numbers should be the ones you want. Here I do it with the last ones available at the moment of writing.

The simplest way to install elixir is using your package manager. Sadly, at the time of writing only Fedora shows the intention to keep its packages up to date. There you can simply sudo dnf install erlang elixir and you are good to go.

Anyway, if you intend to work with several versions of erlang or elixir at the same time, or you are tied to a specific version, you will need to compile it yourself. Then asdf is your best friend.

Terkwood

object Lambda extends App {
  
  sealed trait Term
  sealed trait Var[I <: Index] extends Term
  sealed trait App[T1 <: Term, T2 <: Term] extends Term
  sealed trait Abs[T1 <: Term] extends Term
  sealed trait If[T1 <: Term, T2 <: Term, T3 <: Term] extends Term
  sealed trait Bool[T1 <: Boolean] extends Term

  sealed trait Index

Terkwood

There are certain files created by particular editors, IDEs, operating systems, etc., that do not belong in a repository. But adding system-specific files to the repo's .gitignore is considered a poor practice. This file should only exclude files and directories that are a part of the package that should not be versioned (such as the node_modules directory) as well as files that are generated (and regenerated) as artifacts of a build process.

All other files should be in your own global gitignore file. Create a file called .gitignore in your home directory and add anything you want to ignore. You then need to tell git where your global gitignore file is.

Mac

git config --global core.excludesfile ~/.gitignore

Windows

git config --global core.excludesfile %USERPROFILE%\.gitignore

Terkwood

#Inject javascript into HTML pages from console

An easy way to inject Javascripts into the current loaded dom using the developer console in chrome.

jQuery

var script = document.createElement('script');
script.src = 'http://code.jquery.com/jquery-1.7.2.min.js';

Terkwood

#lang racket
(require parser-tools/lex
         (prefix-in re- parser-tools/lex-sre)
         parser-tools/yacc)
(provide (all-defined-out))

(define-tokens a (NUM VAR))
(define-empty-tokens b (+ - EOF LET IN))
(define-lex-trans number
  (syntax-rules ()

Terkwood

Method for Emulating Higher-Kinded Types in Rust

Intro

I've been fiddling about with an idea lately, looking at how higher-kinded types can be represented in such a way that we can reason with them in Rust here and now, without having to wait a couple years for what would be a significant change to the language and compiler.

There have been multiple discussions on introducing higher-ranked polymorphism into Rust, using Haskell-style Higher-Kinded Types (HKTs) or Scala-looking Generalised Associated Types (GATs). The benefit of higher-ranked polymorphism is to allow higher-level, richer abstractions and pattern expression than just the rank-1 polymorphism we have today.

As an example, currently we can express this type:

Terkwood

{-# LANGUAGE
 TypeOperators, MultiParamTypeClasses, FunctionalDependencies,
 FlexibleInstances, UndecidableInstances
 #-}

module Brainfuck where

{- Usage:

Programs are encoded as cons-lists chained by (:-) and terminated by C0.

Terkwood

Description

[Server] GStreamer ---> HTML [Client]

Require

• gstreamer-1.x
• Browser which supports video tag of HTML5

debian

Terkwood

sudo apt install git cmake clang-3.9 opencl-headers ocl-icd-dev ocl-icd-opencl-dev
sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-3.9 100


git clone https://github.com/doe300/VC4C.git
git clone https://github.com/doe300/VC4CL.git
git clone https://github.com/doe300/VC4CLStdLib.git

cd VC4C
cmake -DBUILD_TESTING=OFF -DSPIRV_FRONTEND=OFF