web-sw-cor24-basic

Browser-based COR24 BASIC v1 sandbox. Write and run 1970s-style line-numbered BASIC programs on the COR24 p-code virtual machine, directly in your browser. Zero install.

Live demo: https://sw-embed.github.io/web-sw-cor24-basic/

Part of the Software Wrighter COR24 Tools Project.

Intro

web-sw-cor24-basic is a zero-install browser sandbox for the COR24 BASIC v1 interpreter. Pick a bundled demo from the dropdown — or paste your own BASIC program into the editor — and run it in a p-code VM compiled to WebAssembly. The UI supports INPUT-driven interactive programs, so REPL-style and turn-based games like startrek work out of the box.

Overview

The BASIC interpreter is Pascal compiled to COR24 p-code (.p24). In this project the p-code runs on an in-browser p-code interpreter (pv24t ported to Rust/WASM — see src/runner.rs) rather than on the COR24 hardware emulator, so the only thing shipped to the browser is the .p24 image and a small loader.

Build time (sibling repo):
  sw-cor24-basic/src/basic.pas  --[p24p compiler]-->  build/basic.p24

Build time (this repo):
  ../sw-cor24-basic/build/basic.p24  --copy-->  assets/basic.p24
  examples/*.bas                         --embed--> Rust string table

Browser runtime:
  basic.p24     -> loaded by pa24r into a Rust p-code interpreter
  BASIC source  -> fed as stdin; auto-appended `RUN` for line-numbered progs
  INPUT         -> pauses execution; host resumes when user submits a line
  stdout bytes  -> streamed into the output panel (auto-scrolls)

• Frontend: Yew 0.21 (CSR), WASM
• P-code loader: pa24r
• P-code interpreter: in-tree port of pv24t
• BASIC interpreter: sw-cor24-basic (Pascal -> p-code)

Build

# 1. Build the BASIC interpreter p-code in the sibling repo
cd ../sw-cor24-basic && ./scripts/build-basic.sh

# 2. Copy the interpreter binary into this project
cp ../sw-cor24-basic/build/basic.p24 assets/

# 3. Dev server (http://localhost:9072/)
./scripts/serve.sh

# 4. Build the release bundle for GitHub Pages
./scripts/build-pages.sh

build-pages.sh holds an exclusive dist/ lock (same lock as serve.sh) so a running dev server cannot race the wasm-bindgen pipeline and leave empty artifacts that manifest as SRI failures in the browser.

Usage

1. Open the app (locally or the live demo link above).
2. Pick a demo from the demo dropdown (or paste your own BASIC into the source panel on the left).
3. Click Run. Output streams into the right-hand panel and auto-scrolls to the bottom.
4. If the program uses INPUT, an input row appears below the output — type your line and press Enter (or click Send). For long-running interactive programs (like startrek) there is no instruction budget: play as long as you like.
5. Reset reloads the current demo's source. Clear wipes the output panel. Stop halts a running program.

Keyboard shortcuts:

• Ctrl/Cmd+Enter — Run from the source panel
• Esc — Stop the running program
• Enter (in the input row) — submit an input line

Demos

Bundled in examples/ and registered in src/demos.rs. Full write-ups in docs/demos.md.

Name	Interactive	Summary
bitwise-demo		BAND/BOR/BXOR/SHL/SHR plus tagged-int helpers and byte packing.
calc		Arithmetic, variables, ABS.
cont-demo		STOP mid-program, then CONT from the REPL to resume.
count		Minimal FOR/NEXT loop, 1..10.
data-demo		DATA/READ/RESTORE, including RESTORE <line> and negative values.
dim-demo		DIM integer arrays, scalar/array namespace separation, expression subscripts.
factorial		Iterative factorial with FOR/NEXT.
fibonacci		First 10 Fibonacci numbers.
fizzbuzz		IF/GOTO branching, 1..15.
guess	✓	Guess-the-number game with INPUT and IF/GOTO.
hello		"HELLO WORLD" one-liner.
memdump		POKE a short message, read it back with PEEK.
mod-demo		MOD operator — clean FizzBuzz without (I/N)*N=I.
on-demo		ON expr GOSUB for O(1) bytecode-style dispatch.
robot-chase	✓	Turn-based 16x16 robot chase on a POKE/PEEK grid. Numpad-style movement, teleport, LRS, and robot-vs-robot collision logic.
startrek	✓	Classic Star Trek game across an 8x8 galaxy. Uses INPUT, GOSUB/RETURN, PEEK/POKE as arrays, and a home-rolled PRNG.
trek-adventure	✓	Numeric-menu text adventure: save the Enterprise before orbit decays. Uses IF/AND, GOSUB/RETURN, room/item state across ~380 lines.

To add a new demo, see docs/adding-demos.md.

Sibling repos

Repo	Role
sw-cor24-basic	BASIC interpreter source
sw-cor24-emulator	COR24 hardware emulator
sw-cor24-pcode	P-code VM, assembler, linker
web-sw-cor24-pcode	Browser p-code debugger (same pattern)
web-sw-cor24-snobol4	Browser SNOBOL4 sandbox (GH Pages pattern)

Links

• Blog: Software Wrighter Lab
• Discord: Join the community
• YouTube: Software Wrighter

Copyright

Copyright (c) 2026 Michael A. Wright

License

MIT -- see LICENSE for details.