History

Damien George bd0bacb637 javascript/library: Use Buffer.alloc() since new Buffer() is deprecated.		2019-04-28 22:14:28 +10:00
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JSBackend.patch	javascript: Add new port targeting JavaScript via Emscripten.	2019-03-13 23:47:32 +11:00
library.h	javascript: Add new port targeting JavaScript via Emscripten.	2019-03-13 23:47:32 +11:00
library.js	javascript/library: Use Buffer.alloc() since new Buffer() is deprecated.	2019-04-28 22:14:28 +10:00
main.c	javascript: Add new port targeting JavaScript via Emscripten.	2019-03-13 23:47:32 +11:00
Makefile	javascript: Fix Emscripten async load, and to compile with modern clang.	2019-03-13 23:52:15 +11:00
modutime.c	javascript: Add new port targeting JavaScript via Emscripten.	2019-03-13 23:47:32 +11:00
mpconfigport.h	javascript: Add new port targeting JavaScript via Emscripten.	2019-03-13 23:47:32 +11:00
mphalport.c	javascript: Fix Emscripten async load, and to compile with modern clang.	2019-03-13 23:52:15 +11:00
mphalport.h	javascript: Fix Emscripten async load, and to compile with modern clang.	2019-03-13 23:52:15 +11:00
node_run.sh	javascript: Add new port targeting JavaScript via Emscripten.	2019-03-13 23:47:32 +11:00
qstrdefsport.h	javascript: Add new port targeting JavaScript via Emscripten.	2019-03-13 23:47:32 +11:00
README.md	javascript: Add new port targeting JavaScript via Emscripten.	2019-03-13 23:47:32 +11:00
wrapper.js	javascript: Fix Emscripten async load, and to compile with modern clang.	2019-03-13 23:52:15 +11:00

README.md

MicroPython.js

MicroPython transmuted into Javascript by Emscripten.

Dependencies

Building micropython.js bears the same requirements as the standard MicroPython ports with the addition of Emscripten (and uglify-js for the minified file).

A standard installation of Emscripten should provide functional code, however if memory errors are encountered it may be worthwhile to modify the tool. emscripten-fastcomp/lib/Target/JSBackend.cpp may require the minor fix found in JSBackend.patch. This patch attempts to address situations where C code running through Emscripten is denied access to Javascript variables leading to false-positives in the MicroPython garbage collector as variables with pointers exclusively in Javascript will be erased prematurely. Refer to Emscripten documentation for instructions on building Emscripten from source.

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);
mp_js_do_str("print('hello world')\n");

Running with HTML

The prerequisite for browser operation of micropython.js is an element with the id mp_js_stdout which receives print events. The following code demonstrates basic functionality:

<!doctype html>
<html>
  <head>
    <script src="build/micropython.js"></script>
  </head>
  <body>
    <div id='mp_js_stdout'></div>
    <script>
      mp_js_stdout.addEventListener('print', function(e) {
        document.write(e.data);
      }, false);

      mp_js_init(64 * 1024);
      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.

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.

mp_js_process_char(char)

Input character into MicroPython repl. char must be of type number. This will execute MicroPython code when necessary.