39bd0b8a0a
This commit improves the webassembly port by adding: - Proxying of Python objects to JavaScript with a PyProxy type that lives on the JavaScript side. PyProxy implements JavaScript Proxy traps such as has, get, set and ownKeys, to make Python objects have functionality on the JavaScript side. - Proxying of JavaScript objects to Python with a JsProxy type that lives on the Python side. JsProxy passes through calls, attributes, subscription and iteration from Python to JavaScript. - A top-level API on the JavaScript side to construct a MicroPython interpreter instance via `loadMicroPython()`. That function returns an object that can be used to execute Python code, access the Python globals dict, access the Emscripten filesystem, and other things. This API is based on the API provided by Pyodide (https://pyodide.org/). As part of this, the top-level file is changed from `micropython.js` to `micropython.mjs`. - A Python `js` module which can be used to access all JavaScript-side symbols, for example the DOM when run within a browser. - A Python `jsffi` module with various helper functions like `create_proxy()` and `to_js()`. - A dedenting lexer which automatically dedents Python source code if every non-empty line in that source starts with a common whitespace prefix. This is very helpful when Python source code is indented within a string within HTML or JavaScript for formatting reasons. Signed-off-by: Damien George <damien@micropython.org>
MicroPython WebAssembly
MicroPython for WebAssembly.
Dependencies
Building webassembly port bears the same requirements as the standard MicroPython ports with the addition of Emscripten (and uglify-js for the minified file).
The output includes micropython.js (a JavaScript wrapper for the
MicroPython runtime) and firmware.wasm (actual MicroPython compiled to
WASM).
Build instructions
In order to build micropython.js, run:
$ make
To generate the minified file micropython.min.js, run:
$ make min
Running with Node.js
Access the repl with:
$ node build/micropython.js
Stack size may be modified using:
$ node build/micropython.js -X stack=64K
Where stack size may be represented in Bytes, KiB or MiB.
MicroPython scripts may be executed using:
$ node build/micropython.js hello.py
Alternatively micropython.js may by accessed by other javascript programs in node using the require command and the general API outlined below. For example:
var mp_js = require('./build/micropython.js');
mp_js_init(64 * 1024);
await mp_js_do_str("print('hello world')\n");
Running with HTML
The prerequisite for browser operation of micropython.js is to listen to the
micropython-print event, which is passed data when MicroPython code prints
something to stdout. The following code demonstrates basic functionality:
<!doctype html>
<html>
<head>
<script src="build/micropython.js"></script>
</head>
<body>
<pre id="micropython-stdout"></pre>
<script>
document.addEventListener("micropython-print", function(e) {
let output = document.getElementById("micropython-stdout");
output.innerText += new TextDecoder().decode(e.detail);
}, false);
var mp_js_startup = Module["onRuntimeInitialized"];
Module["onRuntimeInitialized"] = async function() {
mp_js_startup();
mp_js_init(64 * 1024);
await mp_js_do_str("print('hello world')");
};
</script>
</body>
</html>
MicroPython code execution will suspend the browser so be sure to atomize usage within this environment. Unfortunately interrupts have not been implemented for the browser.
Testing
Run the test suite using:
$ make test
API
The following functions have been exposed to javascript.
mp_js_init(stack_size)
Initialize MicroPython with the given stack size in bytes. This must be called before attempting to interact with MicroPython.
await mp_js_do_str(code)
Execute the input code. code must be a string.
mp_js_init_repl()
Initialize MicroPython repl. Must be called before entering characters into the repl.
await mp_js_process_char(char)
Input character into MicroPython repl. char must be of type number. This
will execute MicroPython code when necessary.