Support for Attributes of Any Type in XML Objects

[carlosleandr]

Problem

Would it be possible to implement the storage of attributes of any type similar to what the Yjs package does? For example, you can see Yjs's implementation here:

https://github.com/yjs/yjs/blob/8dc1296a0bd15e70c573160593c2617e0d772f01/src/types/YText.js#L1235-L1268

Currently, more complex attributes from the Yjs package are arriving in the pycrdt package as strings, making it impossible to retrieve them properly. Check the details in the following references:

pycrdt/python/pycrdt/_pycrdt.pyi

Lines 300 to 307 in 2518513

	def attributes(self, txn: Transaction) -> list[tuple[str, str]]:
	"""Gets all attributes, as a list of `(key, value)` tuples."""
	def attribute(self, txn: Transaction, name: str) -> str | None:
	"""Gets an attribute, or `None` if the attribute does not exist."""
	def insert_attribute(self, txn: Transaction, name: str, value: str) -> None:
	"""Inserts or overwrites an attribute."""

pycrdt/src/xml.rs

Lines 76 to 94 in 2518513

	fn attributes(&self, txn: &mut Transaction) -> Vec<(String, String)> {
	let mut t0 = txn.transaction();
	let t1 = t0.as_mut().unwrap();
	let t = t1.as_ref();
	self.$xinner.attributes(t).map(|(k,v)| (String::from(k), v)).collect()
	}
	fn attribute(&self, txn: &mut Transaction, name: &str) -> Option<String> {
	let mut t0 = txn.transaction();
	let t1 = t0.as_mut().unwrap();
	let t = t1.as_ref();
	self.$xinner.get_attribute(t, name)
	}
	fn insert_attribute(&self, txn: &mut Transaction, name: &str, value: &str) {
	let mut _t = txn.transaction();
	let mut t = _t.as_mut().unwrap().as_mut();
	self.$xinner.insert_attribute(&mut t, name, value);
	}

Additional context

Here is an example of an attribute that I find difficult to retrieve properly due to the various possibilities of values and data organization:

tokens = "[{text: welcome, start: 55, end: 56.4567498}, {start: 56.4567498, text: feature:, end: 60.11}, {start: 60.11, end: 65.0001, text: 12.4564}]"```

[davidbrochart]

I would have to look into it, but maybe @ColonelThirtyTwo has ideas?