feat: Add data buffer support to components (form card). #441

[mturoci]

This PR introduces support for non-packed data buffers within ui.visualization components - form cards.

By-name access is supported as well, buffers behave in the same way for form components as they do in cards.

import time

from h2o_wave import site, ui, data

page = site['/demo']

page.add('example', ui.form_card(
    box='1 1 -1 8',
    items=[
        ui.visualization(
            name='my_plot',
            plot=ui.plot([ui.mark(type='interval', x='=profession', y='=salary', y_min=0)]),
            data=data(fields='profession salary', rows=[
                ('medicine', 23000),
                ('fire fighting', 18000),
                ('pedagogy', 24000),
                ('psychology', 22500),
                ('computer science', 36000),
            ]),
        ),
        ui.visualization(
            plot=ui.plot([ui.mark(type='interval', x='=profession', y='=salary', y_min=0)]),
            data=data(fields='profession salary', rows=[
                ('medicine', 21000),
                ('fire fighting', 17000),
                ('pedagogy', 23500),
                ('psychology', 22300),
                ('computer science', 33000),
            ])
        ),
    ],
))

page.save()

time.sleep(5)

page['example'].my_plot.data[0] = ('medicine', 1000)
page.save()

Closes #441

[mturoci]

@geomodular could you please have a look at the Go code once you have a bit of time? I feel like the code is too verbose and a more idiomatic solution exists.

[geomodular]

Looks good for the go part. Just few notes.

[geomodular]

I'd rewrite this as for ... range for better readability:

for _, key := range keys {
  x = get(x, key)
}

[mturoci]

Sure, the problem is I need to ignore the last entry. Do you think this would be more readable?

for _, key := range keys[:len(keys)-1] {
  x = get(x, key)
}

[geomodular]

This can be rewritten as:

for _, k := range ks[startIdx:] {
  x = get(x, k)
}

[mturoci]

Perfect, exactly what I needed 👍

for _, k := range ks[startIdx : len(ks)-1] {
	x = get(x, k)
}

[geomodular]

v.(string) might not be a string and can cause some trouble here. I'd handle it inside the if scope.

[mturoci]

I guess I need to write a nested if with type cast check, right? Or is there a way how to put it to the existing if statement?

[geomodular]

yes, nested if

[geomodular]

At first I was puzzled with make([]string, 0)) but now I see the function is recursive. Seems ok.