README.md — sigil-web-repl

1# sigil-web-repl

A web-based REPL for trying [Sigil](https://codeberg.org/sigil/sigil) in the browser. Uses `sigil-wasm-runtime` as the WebAssembly runtime and delimited continuations for interactive input/output between JavaScript and Sigil.

5## How it works

The REPL runs Sigil compiled to WebAssembly via Emscripten. It uses delimited continuations (prompts) to yield control back to JavaScript when waiting for user input:

91. `repl-start` begins the REPL and yields waiting for input

102. JavaScript collects input from the user

113. JavaScript calls back into WASM with `web-input-resume`

124. The saved continuation is invoked with the input

135. The REPL evaluates the expression and yields again for the next input

15## Requirements

Building this package requires [Emscripten](https://emscripten.org/) and the `sigil-wasm-runtime` C runtime. This is not a standard Sigil package build; it produces `.js` and `.wasm` output files for browser deployment.

19## Dependencies

21- `sigil-wasm-runtime` - WebAssembly C runtime (from sigil monorepo)

22- `sigil-stdlib` - Standard library

23- `sigil-repl` - REPL commands

24- `sigil-ansi` - Terminal color codes

26## Building

Building requires the Emscripten SDK. On Guix systems, use the included helper script to set up an FHS container with emsdk:

30```bash

31# Enter an Emscripten shell (installs emsdk on first run, ~400MB)

32./scripts/emsdk-shell

34# Install dependencies and build inside the shell

35sigil deps install

36sigil build

37```

39Or run the build directly:

41```bash

42./scripts/emsdk-shell sigil deps install && ./scripts/emsdk-shell sigil build

43```

This compiles the Sigil modules, links them into a web application (`sigil-web-repl.js` and `sigil-web-repl.wasm`), and copies the HTML assets to the output directory.

47## Usage

49Add as a dependency in your `package.sgl`:

51```scheme

52(from-git url: "codeberg:sigil/sigil-web-repl")

53```

55## License

57BSD-3-Clause