Ask HN: What coding stuff do you know off the top of your head?

It comes and goes. I always know most of the syntax of languages I know, but with a bias towards languages I've been using recently or very familiar with. For example, I don't know C++ syntax that well off the top of my head right now, but there have been times in the past when I did, and I could quickly get back into it by coding in C++.

Similar for libraries. There are some libraries like NumPy that I know most common functions off the top of my head, but I still need to look things up frequently. Then there are libraries like Hugging Face where I have to check the documentation every time.

Surprisingly LLM stuff. After years of teaching bootcamps, writing tutorials, I get a good feel of where humans make mistakes. It's similar with LLMs, though in different ways.

Like one of the less common hacks I did was to use YAML over JSON for communicating, because the way it tokenizes data gives it a few extra IQ points when processing YAML. If there's a mistake, I can quickly identify which part of the pipeline it's failing on.

* How to decisively filter competent front end developers in about 3 minutes. Competent people think in terms of graphs that can be walked, accessed, and modified directly. The incompetent ones think in terms of databases in that they can only make queries and expect abstractions and tools to fill their knowledge gap.

* People who write high performance software spend an absurd amount of time measuring things and possibly writing their own tools to provide deeper insights. Other people that talk about performance are hallucinating.

* There are developers that think in terms of other people. Those people put more effort into documentation, content, and architecture. It’s all about what they say. There are developers that think in terms of themselves. They focus on what they believe is easy and stylish. It’s all about what they are willing to do, how to do it, and how it looks.

Everything developers know off the top of their heads come from stuff like those three bullet points and the hours they spend practicing it.

I know how to create hello.com using debug in MS-DOS.

  debug

  a 100
  mov ah,9
  mov dx,120
  int 21
  mov ax,4c00
  int 21

  e 120 "Hello, World!" 0d 0a 24
  r cx 
  80
  n hello.com
  w
  q

  hello

You can try it out here[1]. (Hit F3 twice to exit setup first)

[1] https://www.pcjs.org/software/pcx86/sys/dos/microsoft/6.22/

I know how to exit vim

How to center a div

I kid, I kid :)

Cmd-c, cmd-v