inscapist

Development environment with Nix Flakes and Direnv

This document is targeted at those who seek to build reproducible dev environment across machines, OS, and time.

It maybe easier for remote teams to work together and not spending hours each person setting up asdf/pyenv/rbenv, LSP servers, linters, runtime/libs. Nix is probably the closest thing to Docker in terms of development environment.

Flake is used here because it provides hermetic build, with absolutely no reliance on system environment (be it Arch/Catalina/Mojave). Also it freezes dependencies in flake.lock so builds are reproducible.

This gist provides the setup to develop Java/Clojure/Python applications on Nix. But it can be easily adapted to ruby, nodejs, haskell.

tiran

Negative Python user experience on Debian/Ubuntu

The user experience of Python on a minimal Debian or Ubuntu installation is bad. Core features like virtual environments, pip bootstrapping, and the ssl module are either missing or do not work like designed and documented. Some Python core developers including me are worried and consider Debian/Ubuntu's packaging harmful for Python's reputation and branding. Users don't get what they expect.

Reproducer

The problems can be easily reproduced with official Debian and Ubuntu containers in Docker or Podman. Debian Stable (Debian 10 Buster) comes with Python 3.7.3. Ubuntu Focal (20.04 LTS) has Python 3.8.5.

Run Debian container

njsmith

import trio
import trio.testing

# A simple protocol where messages are single bytes b"a", b"b", b"c", etc.,
# and each one is acknowledged by echoing it back uppercased. So send b"a",
# get b"A", etc.

# To make it easier to shut down, message b"z" causes the receiver to exit.

async def receiver(stream):

ziirish

class Pool:                                                                                                                                                                                                                                  
    def __init__(self, pool_size):                                                                                                                                                                                                           
        self._size = pool_size                                                                                                                                                                                                               
        self.send_channel, self.receive_channel = trio.open_memory_channel(pool_size)                                                                                                                                                        
                                                                        

mfikes

If you wan't a cljs that acts like clj, but for ClojureScript, there are a few minor changes you can make:

First, add the following entry to ~/.clojure/deps.edn under the :deps key:

org.clojure/clojurescript {:mvn/version "1.10.439"}

Then make copies of clj and clojure named cljs and clojurescript, and put those copies on your path.

njsmith

# Ideally, we would manage async access to stdin/stdout/stderr *without*
# setting them to non-blocking mode, because that can break other processes.
# (See https://github.com/python-trio/trio/issues/174 for much more detail.)

# Of course we can call read/write in a separate thread, but then we lose
# cancellation support.

# This file demonstrates a weird hack to make blocking read/write cancellable,
# and thus at least theoretically possible to integrate into Trio as ordinary
# first-class operations.

jgrahamc

addEventListener('fetch', event => {
  event.respondWith(fetchAndCheckPassword(event.request))
})

async function fetchAndCheckPassword(req) {
  if (req.method == "POST") {
    try {
      const post = await req.formData();
      const pwd = post.get('password')
      const enc = new TextEncoder("utf-8").encode(pwd)

jab

Update

Just use https://github.com/ripeworks/iro which gets the challenge below right!

Mac Color Picking Done Right

Picking a Color on Mac is hard. Mainly due to the fact that several applications floating around the web ( AppStore and independant ), grab the color "incorrectly".

Why incorrectly?

lattner

Async/Await for Swift

• Proposal: SE-XXXX
• Authors: Chris Lattner, Joe Groff

Introduction

Modern Cocoa development involves a lot of asynchronous programming using closures and completion handlers, but these APIs are hard to use. This gets particularly problematic when many asynchronous operations are used, error handling is required, or control flow between asynchronous calls gets complicated. This proposal describes a language extension to make this a lot more natural and less error prone.

This paper introduces a first class Coroutine model to Swift. Functions can opt into to being async, allowing the programmer to compose complex logic involving asynchronous operations, leaving the compiler in charge of producing the necessary closures and state machines to implement that logic.

alandipert

(require '[clojure.repl :as repl])

(defmacro &this []
  `(->> (Exception.)
        .getStackTrace
        (map bean)
        (filter #(= "invoke" (:methodName %)))
        (map #(read-string (repl/demunge (:className %))))
        (keep resolve)
        first))