Allow Latex and Markdown formatting in widget options

Problem

It would be cool if users could format options for multiselect boxes and the like using LaTeX and/or Markdown. For example:

st.selectbox('', ['$k_A$', '$k_B$', '$k_D$', 'k<sub>C</sub>'])

Solution

MVP: What’s the smallest possible solution that would get 80% of the problem out of the way?

Possible additions: What are other things that could be added to the MVP over time to make it better?

Preferred solution: If you don’t like the MVP above, tell us why, and what you’d like done instead.

Additional context

HT Emmanual_Pean on the Streamlit forum: https://discuss.streamlit.io/t/html-or-latex-in-selectbox/2002

[CFrez]

This would also be useful to have for labels inside of widgets. This is a screen shot of my use case, with the code, showing what should be if it was done in just text, vs it not rendering within the widget.

st.header('Given Properties')

col11, col12 = st.beta_columns(2)

with col11:
    '---'
    r'Backill Weight $\gamma$ pcf'
    '---'
    'Backfill Friction Angle $\phi$ degrees'

with col12:
    backfill = {}
    st.subheader('Backfill Soil Properties')
    backfill['weight'] = st.number_input(
        r'Backfill Weight $\gamma$ pcf', value=120, step=5)
    backfill['degree'] = st.number_input(
        'Backfill Friction Angle $\phi$ degrees', value=30)

Out of curiosity I just looked at the simple widgets: ✘ st.text('$\phi$') ✘ st.text(r'$\phi$') ✓ st.markdown('$\phi$') ✓ st.latex('\phi') ✓ st.write('$\phi$') ✓ st.title('$\phi$') ✓ st.header('$\phi$') ✓ st.subheader('$\phi$')

Looking into these, it seems like the difference is if it gets treated like text or markdown. Markdown goes through a process of getting rendered by Katex.

Would it be possible to just have any string that goes through a widget get processed the same way as the markdown?

[rafisics]

I am also waiting for this feature to add LaTeX inside st.checkbox() and st.markdown().