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Language Reference

Tastes — Different Ways to Write the Same Thing

Ever had to write a school essay in two different languages? The story is the same, just the words change. That's what tastes do for CatLang.

A taste is just a different "accent" for writing CatLang code. You pick whichever one feels most comfortable to you. They all produce the same CatWeb JSON at the end — no difference in what your buttons do, how your scripts run, or what your page looks like.

In simple terms: It's like choosing between British and American spelling. "Colour" vs "color" — different letters, same meaning. CatLang has two accents: indent (Python style) and bracket (JS style). Pick the one that looks right to you.

#
Your Code → [Taste Reader] → Middle Step → [Output Builder] → CatWeb JSON

The "taste reader" takes whatever style you wrote in and turns it into a middle format. The "output builder" doesn't care which style you used — it just builds the JSON from that middle format. This means all tastes are equally powerful. Nothing is locked behind one style.

#

Uses colons : and indentation (like Python). Clean, easy to read:

python
script "game":
    on loaded:
        l_username = input_get_text("username")
        log("{l_username}")

    fn setup():
        create_table("items")
        log("Ready")

If you've never coded before, start here. It's the simplest to read and write.

Bracket Taste

Uses curly braces { } and semicolons ; (like JavaScript, C++, C#):

python
script "game" {
    on loaded {
        l_username = input_get_text("username");
        log("{l_username}");
    }

    fn setup() {
        create_table("items");
        log("Ready");
    }
}

If you're already comfortable with JS or C-style languages, this'll feel like home.

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Pick your taste when you run Catpile:

bash
cpile --taste indent my_script.cat
cpile --taste bracket my_script.cat

Or save it in your project config so you don't have to type it every time:

json
{"taste": "bracket"}
#

Want to add your own style? Each taste is just a class that reads code and spits out the same middle format.

1. Create the reader file

python
# catpile/tastes/lua.py
from catpile.tastes import Taste
from catpile.ir import Program

class LuaTaste(Taste):
    def parse(self, source: str) -> Program:
        # Your tokenizer + parser here
        # Must return IR Program
        pass

2. Register it

python
# catpile/tastes/registry.py
from .lua import LuaTaste

TASTES = {
    "indent": "catpile.parser.CatpileParser",
    "bracket": "catpile.tastes.bracket.BracketTaste",
    "lua": LuaTaste,  # Add yours
}

3. What your reader must handle

  • Script headers (script "name":)
  • Event handlers (on loaded:, on pressed("btn"):)
  • Function definitions (fn name(params):)
  • Control flow (if/else, repeat, foreach, break, return)
  • Variables and scope prefixes
  • String interpolation ({var} inside strings)
  • Dict/list literals ({key: val}, [item, item])
  • Math expressions (x + y * 2)

Key Patterns

python
# Function detection
if token.kind == "IDENT" and token.value == "fn":
    # function: fn {name}({params}): {body}

# Event detection
if token.kind == "IDENT" and token.value == "on":
    # event: on {name}["("{target}")"]: {body}

# Statement dispatch
if token.value in ("if", "elseif", "else"):
    # conditionals
elif token.value == "repeat":
    # loops
elif token.value == "foreach":
    # foreach loops
elif token.value == "break":
    # break
else:
    # action call
#

See VSCode Extension Guide.