DEV Community: Cole

I Made a Programming Language Where fetch() Is a Syntax Error

Cole — Sun, 01 Nov 2026 19:07:14 +0000

so i made a programming language.

it's called catscript. you print with cat, functions are called hunt, lists are called litter, and if you type fetch anywhere in your code it refuses to run, because this is a cat household.

try it in your browser: https://yupthatscole.github.io/catscript

(no install. the first load takes a few seconds because it's loading python into your browser.)

what it looks like

hunt double(x) {
    bring x * 2
}

kittens = litter["mochi", "pip", "clover"]
cat("there are", size(kittens), "kittens")
cat("double 21 is", double(21))

there are 3 kittens
double 21 is 42

   /\_/\
  ( ^.^ )  purr. it worked.
   > ^ <

every program ends with a cat. a happy one if it worked. an angry one if it didn't.

the cat words

cat(x) prints something (it's also the linux command for printing files, so it's a pun twice)
pspsps("name? ") asks the user for input. you're literally calling them over
hunt makes a function, bring returns something, because cats bring you things
litter[1, 2, 3] is a list
purr and hiss are true and false
empty_bowl is null
knock(x) deletes a variable. knocks it off the table
try { } pounce { } catches errors

errors

errors get a hiss code, a line number, and an insult.

  HISS-404 (line 2): never heard of 'y'. did you make it up?
  did you write this while walking across the keyboard?

   /\_/\
  ( >.< )  HISS.
   > ^ <

dividing by zero is HISS-500: you can't split the fish into zero pieces. a function that calls itself forever is HISS-508: your cat is chasing its tail.

and the dog words (fetch, bark, goodboy, woof, sit, wag) are just banned:

  HISS-403 (line 1, col 1): 'fetch'?? this is a cat household.

how it works

i always assumed making a programming language was some crazy thing. it's actually three parts:

the lexer reads your code and chops it into pieces. cat("hi") becomes cat, (, "hi", )
the parser turns those pieces into a tree, so it knows 1 + 2 * 3 means do the 2 * 3 first
the interpreter walks through the tree and actually runs it

the whole thing is about 1,100 lines of python with no libraries.

the bug

the first time i typed my own code into the playground instead of using the examples, it crashed with a huge python error.

turns out the lexer looks two characters ahead to catch stuff like == and >=. if your code ended on something like ) with nothing after it, it looked at a character that didn't exist and fell off the end of the file.

it worked fine for me because all my example files ended with a blank line. so it only broke the second someone else used it. classic.

now if catscript itself ever crashes, you get HISS-999: catscript tripped over its own tail. this one's not your fault. instead of a wall of python.

it also runs in your browser and vs code

the playground runs the exact same python files in your browser using pyodide, so there's no separate version to keep updated.

there's also a vs code extension that gives .meow files syntax highlighting, a little cat icon, and a run button. dog words get a red squiggle.

try it

playground: https://yupthatscole.github.io/catscript
code: https://github.com/yupthatscole/catscript

write something in catscript and put it in the comments. i want to see what you make

meow

your github repositories are fish now. sorry.

Cole — Sat, 31 Oct 2026 01:11:32 +0000

i was very bored of the green squares on github so i turned them into fish.

github aquarium

basically you enter any github account and it shows their repos as little fish :)

(i drew everything in ms paint btw)

yes, the fish are supposed to look like that. no, i will not be hiring an artist.

try it here: https://github-aquarium.vercel.app

how it works

basically, the site fetches your public repositories using the github api and turns them into fish.

every fish represents a repository, and the species depends on the programming language.

python = fat fish
javascript / typescript = normal fish
rust = crab (obviously)
c / c++ / java = shark
html / css = tiny fish
other languages get different fish too

the number of stars also affects how big the fish is.

you can click on a fish to see which repository it represents, its language, its stars, and a link to the actual repo.

they also swim around, randomly change directions, and attempt to avoid each other. emphasis on attempt.

some examples

linus torvalds

apparently he owns a concerning amount of sharks.

sindresorhus

there are too many fish. send help.

me (yupthatscole)

my repositories are mostly represented by these stupid yellow blobs. i love them.

technical stuff

i built it with vite, vanilla javascript, and pixijs for rendering the aquarium.

it uses github's public api to fetch repository data, so there's no login required.

there's no database, no ai, and no backend. it's just a bunch of poorly drawn fish swimming around based on your github repositories.

there are some limitations, like only displaying up to 25 repositories at once and github's api rate limits, but it works!

anyways

that's pretty much it.

i wanted to make something silly and ended up with a github-powered aquarium.

https://github-aquarium.vercel.app

try putting your username in and tell me what kind of fish you get.

meow

I Built a Task Manager That Insults Me for Using Too Much RAM

Cole — Thu, 29 Oct 2026 21:04:48 +0000

so i was looking at task manager one day and realized how much ram my computer was using.

naturally, instead of closing some programs like a normal person, i decided to make my own task manager.

except this one has a cat.

and he hates you.

introducing meowtop

meowtop is a system monitor i made using python, pyqt6, and psutil.

it shows your cpu, ram, and disk usage, lists running processes, and can notify you when your ram usage gets too high.

but that's boring.

so i added tuft.

tuft is a purple cat who lives inside the app and judges your computer usage. he has different moods, animations, and a concerning number of insults.

if your ram usage gets too high, he'll complain about it. if a program starts using an unreasonable amount of memory, he'll question your decisions.

he also falls asleep when he's bored.

and you can pet him.

he likes that, surprisingly.

how it works

the actual system monitoring is done using psutil, a python library that lets you get information about your computer and running processes.

for example, getting cpu and ram usage is pretty simple:

cpu = psutil.cpu_percent(interval=None)
ram = psutil.virtual_memory().percent

then i use PyQt6 to display everything in a desktop application.

the interface updates every couple of seconds, and the process list gets refreshed separately so the entire app doesn't freeze while checking everything that's running.

because making a task manager that lags your computer would be a little embarrassing.

giving tuft a personality

tuft uses a sprite sheet with different animations for different moods.

he can be normal, concerned, confused, angry, happy, or asleep.

his mood changes depending on what's happening with your computer.

i also made him clickable, so you can pet him. he'll get happy for a few seconds before going back to judging you.

there's also a button specifically for roasting your computer.

completely necessary feature.

the windows defender incident

once i finished, i tried packaging everything into an exe using pyinstaller.

it worked.

and then windows defender decided meowtop was a trojan.

so that's great.

from what i've investigated, it might be a false positive related to how pyinstaller packages executables, but i haven't confirmed that yet.

for now, i'm just publishing the source code instead of distributing an exe that windows is actively trying to delete.

apparently tuft is a national security threat.

anyway

this started as a tiny python window showing two percentages and somehow turned into an entire system monitor with an animated cat.

it's not meant to replace windows task manager, but it was a fun project and i learned more about pyqt6, system monitoring, threads, and making desktop interfaces.

the source code is on github if you want to try it yourself, look through it, or see how it works.

github: meowtop

meow.

meet catweb: a browser for windows (with a cat)

Cole — Sun, 25 Oct 2026 22:49:40 +0000

so i have a browser now. it's called catweb, a pixel cat named tuft lives on the new tab page.

download: https://yupthatscole.github.io/catweb-releases/

what it is

catweb is a windows browser written in rust.

websites run on webview2, the same engine microsoft edge uses, so most sites just work. catweb draws everything around the page itself: tabs, address bar, menus, settings, downloads, and tuft.

there's also catweb native, a from-scratch rendering engine. it's an experimental side project, and tabs using it get an "Experimental" label. don't sign in to anything in those.

what it does

built-in ad and tracker blocking (easylist), toggle per site
tries https first, strips tracking junk from links
private tabs that forget everything when closed
tabs in the title bar, drag to reorder, reopen closed tabs (ctrl+shift+t)
address bar suggestions, bookmarks bar, history, downloads panel
imports your chrome bookmarks and history
themes and accent colors (default is "lavender soft")
updates itself and checks a signature before installing anything
silly settings, off by default. yes, the switches meow.
privacy
no accounts, no analytics, no telemetry. on its own, catweb only talks to:

github, once a day, to check for updates (can be turned off)
sites you visit, to grab their icons (never in private tabs)
microsoft smartscreen, for dangerous sites and downloads (on by default, can be turned off)
history and bookmarks stay on your pc. catweb doesn't save passwords.

it hasn't had an outside security audit, so i wouldn't use it for banking yet.

the smartscreen thing

catweb isn't code-signed (that costs money every year), so windows will warn you. click "More info", then "Run anyway".

if you want to check it first:

virustotal: https://www.virustotal.com/gui/file/ea48b93c00d2345afdcbc42327ce868ffac0f0fcb33bd4c1df12320d2c864cec/detection
every release has a sha-256 checksum next to the download

what's next

a vpn/proxy option someday, making catweb native good enough for real sites.

bugs

found one? open an issue at https://github.com/yupthatscole/catweb-releases/issues and say what you did and what happened.

meow

I built a little social site with zero npm dependencies (and a cat runs it)

Cole — Sun, 25 Oct 2026 21:56:35 +0000

I've been building catcloud, a small corner of the internet where everyone gets their own page to decorate, kind of like old GeoCities/MySpace pages. It's run by Tuft, a purple pixel cat who is officially the CEO. He writes memos.

You get a page at catcloud.party/@yourname that you can paint however you want: colors, layouts, pictures, or raw HTML/CSS. There are guestbooks, a mini pixel cat on every page that visitors can pet and feed, trading cards, a small arcade, and a live hangout room where everyone's mini cats walk around together.

Here's how it's built, because a few parts were fun to figure out.

Zero dependencies
The whole thing runs on plain Node 22: node:http for the server and the built-in node:sqlite for the database. There's nothing in node_modules, no framework, and no build step. The frontend is plain JavaScript too.

Hosting it for free
It runs on the Cloudflare Workers free plan. The whole app lives inside one SQLite-backed Durable Object, so it's still "one server with one database", just on someone else's computer. The same code also runs on a normal PC with npm start.

Letting people write raw HTML safely
People can put their own HTML and CSS on their page. To make that safe, each page renders inside a sandboxed iframe with a strict Content-Security-Policy and no scripts allowed. That way someone's page can look however they want, but it can't run code or touch anyone's account.

Pixel art without image editors
Most of the art (game sprites, furniture, cat clothes) is drawn as little text grids in JavaScript, where each letter is a color. The browser turns them into outlined pixel sprites at 4x. It's a lot easier to tweak a hat when the hat is a string.

Games that are hard to cheat
The arcade pays out coins, so people would want to cheat it. The server picks every round from a seed, then re-checks the results when you finish: it replays the round and checks that you didn't move faster than the game allows. If the numbers don't add up, no coins.

A live room on a free plan
The hangout room uses Server-Sent Events. To keep traffic tiny, the cats' walking paths come from a shared seed, so the server only sends "this cat did something" events, never positions. Every browser works out where each cat is on its own.

Try it
It's free and still new, so it's pretty quiet right now. If you make a page, drop your link in the comments and I'll sign your guestbook. I'd love feedback on what's confusing or broken!

👉 https://catcloud.party