129 lines
3.0 KiB
Markdown
129 lines
3.0 KiB
Markdown
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MicroPython.js
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==============
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MicroPython transmuted into Javascript by Emscripten.
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Dependencies
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------------
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Building micropython.js bears the same requirements as the standard MicroPython
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ports with the addition of Emscripten (and uglify-js for the minified file).
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A standard installation of Emscripten should provide functional code, however
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if memory errors are encountered it may be worthwhile to modify the tool.
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`emscripten-fastcomp/lib/Target/JSBackend.cpp` may require the minor fix
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found in JSBackend.patch. This patch attempts to address situations where
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C code running through Emscripten is denied access to Javascript variables
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leading to false-positives in the MicroPython garbage collector as variables
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with pointers exclusively in Javascript will be erased prematurely.
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Refer to Emscripten documentation for instructions on building Emscripten
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from source.
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Build instructions
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------------------
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In order to build micropython.js, run:
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$ make
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To generate the minified file micropython.min.js, run:
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$ make min
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Running with Node.js
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--------------------
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Access the repl with:
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$ node build/micropython.js
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Stack size may be modified using:
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$ node build/micropython.js -X stack=64K
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Where stack size may be represented in Bytes, KiB or MiB.
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MicroPython scripts may be executed using:
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$ node build/micropython.js hello.py
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Alternatively micropython.js may by accessed by other javascript programs in node
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using the require command and the general API outlined below. For example:
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```javascript
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var mp_js = require('./build/micropython.js');
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mp_js_init(64 * 1024);
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mp_js_do_str("print('hello world')\n");
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```
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Running with HTML
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-----------------
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The prerequisite for browser operation of micropython.js is an element with
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the id `mp_js_stdout` which receives `print` events. The following code
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demonstrates basic functionality:
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```html
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<!doctype html>
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<html>
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<head>
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<script src="build/micropython.js"></script>
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</head>
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<body>
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<div id='mp_js_stdout'></div>
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<script>
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mp_js_stdout.addEventListener('print', function(e) {
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document.write(e.data);
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}, false);
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mp_js_init(64 * 1024);
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mp_js_do_str('print(\'hello world\')');
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</script>
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</body>
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</html>
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```
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MicroPython code execution will suspend the browser so be sure to atomize usage
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within this environment. Unfortunately interrupts have not been implemented for the
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browser.
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Testing
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-------
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Run the test suite using:
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$ make test
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API
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---
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The following functions have been exposed to javascript.
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```
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mp_js_init(stack_size)
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```
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Initialize MicroPython with the given stack size in bytes. This must be
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called before attempting to interact with MicroPython.
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```
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mp_js_do_str(code)
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```
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Execute the input code. `code` must be a `string`.
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```
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mp_js_init_repl()
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```
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Initialize MicroPython repl. Must be called before entering characters into
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the repl.
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```
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mp_js_process_char(char)
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```
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Input character into MicroPython repl. `char` must be of type `number`. This
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will execute MicroPython code when necessary.
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