feat: serialize pd.Dataframe as csv

[manzt]

Requires that gosling.[dev] for installation. If we can support this feature without the data-server (using the json data-type), but this would currently lead to embedding the full dataset multiple times in the chart definition becaused we don't support data references: gosling-lang/gosling.js#508

import gosling as gos # import registers `pd.Dataframe.gos` namespace
import pandas as pd

df = pd.Dataframe(...)
data = df.gos.csv(...)
gos.Track(data).mark_bar().encode(...)

It might be good to dig into these methods more deeply for safer serialization of dataframes: https://github.com/altair-viz/altair/blob/master/altair/utils/data.py#L178-L217

[manzt]

Thanks for pointing this out. Let me take a look!

[sehilyi]

This is an exciting feature!

I tried to replicate one of the examples that require data transformation, and using Pandas is so satisfying for this!