Add the ability to programatically re-run the streamlit script

Problem

I am building a small labeling too where I read in an example, the user will select labels from a list of check boxes and click submit in order to save the labels, when they submit a field in the data for it being labeled is added so in the next read it skips that example. The problem is that the submit button will cause a rerun where the labels are collected and saved but it doesn’t cause another re-run that will cause the data to be reread (this will move the app on to the next question)

Solution

I think a solution would be a st.rerun() function that you can call to reexecute the script from the top. In my cause this would be called after my save and trigger a re-read. Basically it would do the same thing I am currently using a second Next button for but remove the need for user interaction.

[SimonBiggs]

The code for this has changed to:

def rerun():
    raise st.script_runner.RerunException(st.script_request_queue.RerunData(None))

[SimonBiggs]

A neater fix seems to be the following:

import streamtlit as st

def rerun():
    raise st.ScriptRunner.RerunException(st.ScriptRequestQueue.RerunData(None))

Worked this out from the comment written over at:

# Data attached to RERUN requests
RerunData = namedtuple(
    "RerunData",
    [
        # WidgetStates protobuf to run the script with. If this is None, the
        # widget_state from the most recent run of the script will be used instead.
        "widget_state"
    ],
)

Meaning, passing None to RerunData defaults to no change in state.