ISETL WebTypeScript · WebAssemblyAn interactive language for exploring mathematics, made usable in a modern browser. Write a program, inspect its sets, and draw with the original interpreter.
This project began as a place to preserve ISETL sources, executables, and manuals. The web version lets that language keep being used: no old operating system, installation, or account required. The original C interpreter runs locally through WebAssembly.
An editor with syntax highlighting, a persistent console, runnable examples, and local file import and export. Your programs execute in your browser.
Compare variables with union, intersection, difference, and symmetric difference. Follow the members through a diagram and step through each region.
The original drawing commands and plotting libraries render on a canvas beside your code.
The Cantor example constructs a subset that is missing from a finite map. It makes the diagonal argument tangible; it is an illustration, not a formal proof checker.
Read the Cantor proof
Examples, bug reports, accessibility improvements, documentation, and browser testing are welcome. The TypeScript runtime can also be used independently in another app.
The new web code is MIT licensed. The original interpreter and archived materials retain their own notices; the original manual permits copying subject to a restriction against sale for profit.