Thomas Bandt aspnetde

[F#] Implementing Coroutines (async/await) using continuations

Coroutines or async/await is not a new concept as it was named in 1958 by Melvin Conway. Coroutines had support in languages such as Simula(1962), Smalltalk(1972) and Modula-2(1978) but I think one can argue that coroutines came into mainstream with C# 5(2012) when Microsoft added async/await to C#.

The problem with subroutines

A thread can only execute a single subroutine at a time as a subroutine starts and then runs to completion. In a server environment subroutines can be problematic as in order to service connections concurrently we would usually would start a thread per connection, this was the idiom a few years ago. A thread depending on the operating system and settings needs about 1 MiB of user stack space meaning 1,024 threads needs 1 GiB of for just user stack space. In addition there's the cost of kernel stack space, book-keeping and scheduling of threads. This drives cost of VM/hardwa

Ever wanted to delete all your likes/favorites from Twitter but only found broken/expensive tools? You are in the right place.

Go to: https://twitter.com/{username}/likes
Open the console and run the following JavaScript code:

setInterval(() => {
  for (const d of document.querySelectorAll('div[data-testid="unlike"]')) {
    d.click()
 }

Example of Kamal deployment from Github Actions.

Add your applications .env variables to the Github repo as a repository secret, you can find this under the repo settings => secrets and variables => actions

https://github.com/username/repo_name/settings/secrets/actions

you are going to need an ssh private key that your deployment server is aware of (add public key to servers .ssh/authorized_keys) and add the ssh private key as a repo secret

create action workflows

	// A reply to: https://twitter.com/davidfowl/status/1282445306261471232
	// This implements a connection of some kind that can be started and stopped asynchronously.
	// We must ensure that we don't try to start it while it is stopping or vice-versa.

	// A few internal types first...

	/// Contains whatever state needs to be held on to while connected.
	type private ConnectedState = { Id: int }

	/// The state of the internal agent. Describes the current status of the connection,

	// ========= Event Sourcing in a nutshell

	(*
	FriendlyName: string
	Aggregate friendly name.

	Initial: 'State
	Initial (empty) state we will start with.

	Decide: 'Command -> 'State -> 'Event list