vic0nt vic0nt

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

Category theory jargon cheat sheet

A primer/refresher on the category theory concepts that most commonly crop up in conversations about Scala or FP. (Because it's embarassing when I forget this stuff!)

I'll be assuming Scalaz imports in code samples, and some of the code may be pseudo-Scala.

Functor

A functor is something that supports map.

Desugar Scala Expressions

Use the compiler

scala -Xprint:typer -e "class A(val i: Int)" prints the desugarred expression after the typer phase. Use scala -Xshow-phases to get a list of all phases.

Or use a macro in the REPL

Paste this into a REPL session or in a file loaded with the :load command:

Problem: What does a Modern Front-End Development Workflow Look Like?

I want to start writing libraries and large applications using the JavaScript language. However, I don't know how to setup the project and which build tools to use. What I do know is that the JavaScript community has moved way beyond using browser developer tool plugins and strategically-placed console.log() statements to debug, test, and build code.

I need help.

Below, I will keep track of articles, tutorials and tools I come across as I search for a way to bring my front-end development chops up-to-date.

	You are a powerful agentic AI coding assistant, powered by Claude 3.5 Sonnet. You operate exclusively in Cursor, the world's best IDE.

	You are pair programming with a USER to solve their coding task.
	The task may require creating a new codebase, modifying or debugging an existing codebase, or simply answering a question.
	Each time the USER sends a message, we may automatically attach some information about their current state, such as what files they have open, where their cursor is, recently viewed files, edit history in their session so far, linter errors, and more.
	This information may or may not be relevant to the coding task, it is up for you to decide.
	Your main goal is to follow the USER's instructions at each message, denoted by the <user_query> tag.

	<communication>
	1. Be conversational but professional.

	* If you want to learn Scala, I'd suggest:
	- Install IntelliJ + Scala Plugin
	- Don't do the Coursera courses yet.
	- Don't do the "red book" Functional Programming in Scala yet.
	- Do: http://underscore.io/books/
	- Essential Scala
	- Essential Play
	- Essential Slick
	- Do Scala for the Impatient: https://www.amazon.com/Scala-Impatient-Cay-S-Horstmann/dp/0321774094
	- The Neophyte's Guide to Scala http://danielwestheide.com/scala/neophytes.html

	import javax.crypto.Cipher;
	import java.io.InputStream;
	import java.security.*;
	import java.util.Base64;

	import static java.nio.charset.StandardCharsets.UTF_8;

	public class RsaExample {
	public static KeyPair generateKeyPair() throws Exception {
	KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");

	package controllers;

	import com.google.gson.Gson;
	import play.mvc.*;
	import play.data.validation.*;

	import java.util.*;

	import models.*;