qbjc

qbjc is a QBasic to JavaScript compiler. It can compile a QBasic / QuickBASIC program to:

• A standalone executable Node.js script, with zero external dependencies; or
• An ES6 module that can be imported and executed in both Node.js and browser environments.

Try it out in the qbjc playground: 👉 qbjc.dev 👈

Usage

qbjc playground

The qbjc playground (👉 qbjc.dev 👈) allows you to edit and run QBasic / QuickBASIC programs directly in the browser, no installation required.

Command line usage

# Install qbjc from NPM
npm install -g qbjc

# Compile hello.bas and write output to hello.bas.js
qbjc hello.bas

# Run the compiled program
./hello.bas.js

# ...or run hello.bas directly:
qbjc --run hello.bas

# See all command line options
qbjc --help

API usage

Compiling a QBasic program:

import {compile} from 'qbjc';

...
const {
  // Compiled JavaScript code.
  code,
  // Sourcemap for the compiled JavaScript code.
  map,
  // Abstract syntax tree representing the compiled code.
  astModule,
} = await compile({
  // QBasic source code.
  source: 'PRINT "HELLO WORLD"',
  // Optional - Source file name (for debugging information).
  sourceFileName: 'hello.bas',
  // Optional - Whether to bundle with Node.js runtime code in order
  // to produce a standalone script.
  enableBundling: true,
  // Optional - Whether to minify the output.
  enableMinify: false,
});

Executing the compiled code:

• In browsers (using xterm.js):

  import {Terminal} from 'xterm';
  import {BrowserExecutor} from 'qbjc/browser';
  import {compiledModule} from './hello.bas.js';
  
  // Set up xterm.js Terminal instance
  const terminal = new Terminal(...);
  
  await new BrowserExecutor(terminal).executeModule(compiledModule);

• In Node.js:

  import {NodeExecutor} from 'qbjc/node';
  import {compiledModule} from './hello.bas.js';
  
  await new NodeExecutor().executeModule(compiledModule);

• In Node.js with bundling enabled (i.e. compiled with enableBundling: true):

  import {run} from './hello.bas.js';
  await run();

Compatibility

For detailed compatibility information on individual commands and functions, see 👉 Implementation Status.

What works:

• Core language features

  • Control flow structures - loops, conditionals, GOTO, GOSUB etc.
  • Data types - primitive types, arrays and user-defined types (a.k.a. records)
  • Expressions - arithmetic, string, comparison, boolean
  • SUBs and FUNCTIONs
  • DATA constants
  • Many built-in commands and functions like VAL, STR$, INSTR, MID$

• Text mode

  • Basic text mode I/O - PRINT, INPUT, INKEY$, INPUT$ etc.
  • Text mode screen manipulation - COLOR, LOCATE etc.
  • Note that the current implementation depends on a VT100-compatible terminal emulator.
    • On Windows, this means using WSL or something like PuTTY.
    • In the browser, the implementation uses xterm.js.

• It's just enough to run the original NIBBLES.BAS game that shipped with QBasic:

What doesn't work (yet):

• Graphics and audio
• Events - ON ERROR, ON TIMER etc.
• OS APIs like file I/O, CALL INTERRUPT etc.
• Direct memory access - PEEK, POKE etc.
• Less common syntax, inputs or options
• ...and more - contributions are welcome!

About

qbjc is distributed under the Apache License v2.