Ask HN: What do you code when learning a new language/framework?

a simple (not fully compliant) http 1 server from raw sockets usually gives me a good overview of the languages features and limitations

A memcached server:

https://ronreiter.medium.com/how-to-write-a-memcached-server...

Is it useless if it has value to the creator?

Me: Normally backend/data-processing stuff, senior level.

My "hello world" project is almost always Conway's Game of Life, and I try pretty hard to follow the idioms of the language when I do it.

I like Conway's Game of Life because it's easy enough to not be too frustrating, but challenging enough to where you actually have to think about the problem a bit, at least if you're planning on following language idioms. Usually I just "render" to the command line, though occasionally I will get ambitious and figure out SDL or OpenGL bindings.

Admittedly most of my projects involve servers in some way, so after I've done the Game of Life, I usually start playing with the networking libraries like ZeroMQ and the libraries to call command-line programs, and I make a distributed video processor using ffmpeg.

my classic is an mbox filter. Read a mailbox, determine who sent it and when, and rewrite an output mailbox with different filter conditions applied (e.g., only mails from nigerian princes, only mails younger than a month). determines for me how file I/O, error handling, indices / data structures pointing to messages work, sorting, etc.