Feature proposal: cell output export

[marckruzik]

Hello, I am glad to see the work which has been done here!

I am using a lot of notebooks, and I would like to automate them, and get specific cells output.
I think the easier way to do so would be to run a notebook using dotnet-repl, identify a cell, and get its raw output as a file.
I have a crude pipeline, and I am looking for a way to improve it, either with existing nugets, or by suggesting a feature.

The problems

1: a way to give a name or id to a cell
I am talking about a user defined name, not an automatic one like the cell number.

• Using ipynb format, we can have a first line comment such as #id:myFinalOutput, which can be parsed later from the cell source.
• Using trx format, the first line of the cell is used to create a parameter testName="Cell X: first_line_of_the_cell".
• Maybe a magic command would be better?

2: a way to get a raw output of the cell

• Using ipynb format, the output looks like this:

"outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\r\n",
      "1\r\n",
      "2\r\n",
      "3\r\n"
     ]
    }
   ]

• Using trx format, the output looks like this;

      <Output>
        <StdOut>0
1
2
3</StdOut>
      </Output>

It's possible to parse the files. But I think it would be better if dotnet-repl outputs directly the raw output to a a file.

Proposal for one output

The notebook

#!cellid myFinalOutput
Console.WriteLine("Hello World");

The command line
dotnet repl --run /path/to/notebook.ipynb --output-path /path/to/output.txt --cellid myFinalOutput

The output (output.txt)
Hello World

As the output is raw, it could also be some html.

Proposal for several outputs

Managing several outputs for several cells.

The notebook

#!cellid myIntermediaryOutput
2 + 2

#!cellid myFinalOutput
Console.WriteLine("Hello World");

The command line
dotnet repl --run /path/to/notebook.ipynb --output-path /path/to/folder --cellid myIntermediaryOutput,myFinalOutput

• myIntermediaryOutput.txt
  4
• myFinalOutput.txt
  Hello World

[jonsequitur]

VS Code Insiders has added support for cell tags, which can be parsed from the .ipynb. Microsoft.DotNet.Interactive.Documents](https://www.nuget.org/packages/Microsoft.DotNet.Interactive.Documents/) might need to add support for it but it should be very minor change.