This reduces memory use by reusing objects, and improves identity/equality
relationships of JavaScript objects on the Python side.
In 77bd8fe5b8 PyProxy's were reused when the
same Python object was proxied across to JavaScript. This commit does the
same thing but for JsProxy's going from JS to Python. If an existing
JsProxy reference exists for the JS object about to be proxied across, then
it's reused.
This helps reduce the number of alive objects (memory use), and, more
importantly, improves equality relationships of JavaScript objects on the
Python side. Eg we now get, on the Python side:
import js
print(js.Object == js.Object)
that prints True. Previously it was False.
Note that this change does not make identity work with `is`, for example
`js.Object is js.Object` is actually False. With more work that could be
made True but for now we leave that as-is.
The behaviour with this commit matches Pyodide semantics.
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>
This reverts part of commit fa23e4b093, to
make it so that Python `None` converts to JavaScript `null` (and JavaScript
`null` already converts to Python `None`). That's consistent with how the
`json` module converts these values back and forth.
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>
