# JupyterLab Doc

## Installation
Install JupyterLab

1. Probably the easiest way is to use [conda](https://conda.io/en/latest/) (note that you can also use Miniconda which would a smaller installation if you don't want to have the entire Anaconda)
2. Create a conda environment for sage: `conda create -n sage` (note: your folder will be called `sage`. you can also name this folder something else other than `sage`)
4. Install JupyterLab: `conda install -c conda-forge jupyterlab=1.0.1`

Now you can start JupyterLab using the command `jupyter lab` on the terminal while in your sage environment.

Install Sagemath kernel

1. In a command window, run the command
`jupyter kernelspec install /path/to/sage/local/share/jupyter/kernels/sagemath --user`
(if you have multiple Sagemath installations, you can do `/path/to/sage/local/share/jupyter/kernels/sagemath/ --user --name ChosenName`)

2. To link Jupyterlab to Sage, first open the file `kernel.json` which may be located in `Library/Jupyter/kernels/sagemath/kernel.json` or in a different path. To look up the path, first look up the available kernels.
* To check the available kernels, type `jupyter kernelspec list` or `sage kernelspec list` (I am not sure which one is correct - someone please edit this line)
* Add
`"env":{"SAGE_ROOT":"/path/to/sage"}`
at the end of the dictionary in the file `kernel.json`.

To make Jupyterlab an app in Chrome:

1) If this is your first time modifying Jupiter Notebook configuration, generate it by typing in a command window:
`jupyter lab --generate-config`
2) Edit the file
`~/.jupyter/jupyter_notebook_config.py`
and add the line
`c.LabApp.browser = ‘/path/to/Google Chrome/ —-app=%s’`
For example, on a Mac, add the line
`c.LabApp.browser = '/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --app=%s’`

## Activating and deactivating the Conda environment (I am not sure whether this is the proper term - please edit)
1. To activate Jupyter Lab, go to the terminal and type `conda activate [Name of your conda environment, which is this example is Sage]`
2. Once the environment is activated, type `jupyter lab` on the terminal. This should open a browser (your default browser) running JupyterLab.
3. To deactivate, type `conda deactivate`

## Keyboard shortcuts that may be useful
We want to (re)define some keyboard shortcuts
* Activate the next tab: `Ctrl+PageDown`
* Activate the previous tab: `Ctrl+PageUp`
* Set syntax highlighting for current editor: `Ctrl+P`
* New Console for noteook / texteditor: `Alt+B`

In JupyterLab open the Advanced Settings Editor (`Settings -> Advanced Settings Editor`) and open `Keyboard Shortcuts`.
Copy and paste the following to the editor and save. This code works for Jupyterlab >= 1.0.0

{
    "shortcuts": [
        {
            "command": "application:activate-next-tab",
            "keys": [
                "Ctrl PageDown"
            ],
            "selector": "body"
        },
        {
            "command": "application:activate-previous-tab",
            "keys": [
                "Ctrl PageUp"
            ],
            "selector": "body"
        },
        {
            "command": "codemirror:change-mode",
            "keys": ["Accel P"],
            "args": { "name": "Python" },
            "selector": ".jp-FileEditor"
        },
       
        {
            "command": "filemenu:create-console",
            "keys": ["Alt B"],
            "selector": ".jp-FileEditor"
        },
    ]
}

## Problems
* `view(...)` "freezes cell"
* `attach(*files)` does not work

## Other usefull stuff
* [Enable Widgets](https://ipywidgets.readthedocs.io/en/stable/user_install.html)