Multiple inputs/outputs for "Python Script"

[borondics]

Orange version

3.4.dev0+1b1813c

Expected behavior

Often times it would be extremely useful to be able to connect several inputs to the Python Script widget and be able to do operations with them to generate one or multiple outputs.

Would it be possible to have in_data and out_data as an array and handle arbitrary number of inputs/outputs? (Or at least for the input part, because I see how outputting an array can confuse other widget functionality)

Actual behavior

Python Script accepts only one input and provides one output channel.

[janezd]

This wouldn't be difficult to implement, but we have to decide what it will look like.

The natural way to access multiple data sets would be by indexing, e.g. in_data[0], in_data[1]... If we do so, we break compatibility with the existing code where in_data[0] used to be the first data instance.

We could let in_data be the Table, if there is just one, or a list of tables, if there are multiple. This wouldn't work well for scripts that can accept multiple tables but also work with just a single table.

One solution may be to have in_data.get_token(i), which returns the i-th table (we should come up with a better name than get_token. If there is just one signal, in_data would still contain the table, but also have a get_token method. If there are multiple signals, in_data without get_token would be ... hm, what?

The technical implementation of this is not very clean, but it would work.

[jschueller]

hi, news on this ?

[janezd]

@jerneju started working on it in #2418, but the current PR breaks compatibility with existing code. What about this option:

• in_data contains the table if there is exactly one; None otherwise
• multi_data is a list of tables; it can be empty, have a single table or multiple tables.

This solution doesn't require monkey-patching (like get_token above), and it supports scripts that expect a single table, as well as scripts that accept multiple tables but can work with one.

[janezd]

I'm sorry, I'm stupid. That's what's essentially already in #2418.

[kernc]

Fixed in #2506.