📚 Context

st.write() does something awesome with classes and generic object instances: it passes them to st.help() so the user can see that class's/object's docstring, member variables, methods, and much more.

However, if the user called st.write() on an instance of a Python dataclass, all that would be displayed was the class's name. This PR fixes that, by making the behavior for dataclass instances match the one described above.

• What kind of change does this PR introduce?

  • Bugfix
  • Feature
  • Refactoring
  • Other, please describe:

🧠 Description of Changes

• Add bullet points summarizing your changes here

  • This is a breaking API change
  • This is a visible (user-facing) change

👁️ What it looks like

Given this code...

import streamlit as st
from dataclasses import dataclass


@dataclass
class Vector:
    """A little 2D vector class."""
    x = 0
    y = 0

    def length(self):
        return x**2 + y**2


v = Vector()
v.x = 10
v.y = 20

st.write(v)

...this is what you get today

...and this is what you get after this PR

🧪 Testing Done

• Screenshots included
• Added/Updated unit tests
• Added/Updated e2e tests - No need. This change doesn't impact any of the rendering logic beyond what's already caught in the unit test.

🌐 References

None

Contribution License Agreement

By submitting this pull request you agree that all contributions to this project are made under the Apache 2.0 license.