Instead of raising KeyError. These semantics match JavaScript behaviour
and make it much more seamless to pass Python dicts through to JavaScript
as though they were JavaScript {} objects.
Signed-off-by: Damien George <damien@micropython.org>
This adds a new undefined singleton to Python, that corresponds directly to
JavaScript `undefined`. It's accessible via `js.undefined`.
Signed-off-by: Damien George <damien@micropython.org>
And change Py None conversion so it converts to JS undefined.
The semantics for conversion of these objects are then:
- Python None -> JavaScript undefined
- JavaScript undefined -> Python None
- JavaScript null -> Python None
This follows Pyodide:
https://pyodide.org/en/stable/usage/type-conversions.html
Signed-off-by: Damien George <damien@micropython.org>
This commit defines a new `JsException` exception type which is used on the
Python side to wrap JavaScript errors. That's then used when a JavaScript
Promise is rejected, and the reason is then converted to a `JsException`
for the Python side to handle.
This new exception is exposed as `jsffi.JsException`.
Signed-off-by: Damien George <damien@micropython.org>
The `reason` in a rejected promise should be an instance of `Error`. That
leads to better error messages on the JavaScript side.
Signed-off-by: Damien George <damien@micropython.org>
When a Promise is rejected on the JavaScript side, the reject reason should
be thrown into the encapsulating generator on the Python side.
Signed-off-by: Damien George <damien@micropython.org>
An exception on the Python side should be passed to the Promise reject
callback on the JavaScript side.
Signed-off-by: Damien George <damien@micropython.org>
With this commit, `interpreter.runPythonAsync(code)` can now be used to run
Python code that uses `await` at the top level. That will yield up to
JavaScript and produce a thenable, which the JavaScript runtime can then
resume. Also implemented is the ability for Python code to await on
JavaScript promises/thenables. For example, outer JavaScript code can
await on `runPythonAsync(code)` which then runs Python code that does
`await js.fetch(url)`. The entire chain of calls will be suspended until
the fetch completes.
Signed-off-by: Damien George <damien@micropython.org>
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>
Damien George