Notebook

Python Notebook

Install Python extension
Open samples/hello.py. Python notebook related commands should be rendered as codelens
- Click Run Cell
- For first time users, it will install Notebook related dependencies, which might take a few minutes
- Once all the dependencies installed, you can
Open samples/hello.ipynb. A jupyter notebook will be opened in a webview
- Every cell in the editor is a monaco editor, in which you can write code with language features support, like Auto Complete, Hover and Siganature help.

open a ipynb file
- a text editor is opened first, then closed and finally a webview is opened
editors in the webview
- load monaco-editor through webpack
- no web worker in webview, everything then runs in the main thread, e.g., link detection
- every notebook cell is a monaco editor with its own standalone services.
  - 👓standalone services can be shared across different instances of monaco editor.
- full monaco editor created even when it's readonly mode
  - 👓colorize api can be used here
themes
- tokenization with textmate web assembly
language features
- language services run in the main extension side, which listen to changes and requests from the webview
  - model creation/deletion and content change
  - completion, hover and signature requests
  - 👓 it's not using monaco-languageclient
keybindings
- listen to keyboard events on the editor and handle simple ones meta+up/down, meta+s.
- the rest of them are all Monaco builtin ones
missing pieces
- debugging
- keymaps/commands from VS Code
- decorations/codelens/etc contributed by other extensions

Editor
- Custom Editor with mixed rendering:
  - markdown, html, latex, svg, text. Sanitize and render as HTML
  - source code with Monaco Editor
- Every cell and output is a web component
Data are loaded through Notebook Provider
- the shape is similar to all other providers
- provide available kernels
- notebook manager (for managing notebook file in the custom editor)
  - provides content (Cells)
  - provides a session manager
    - creates a session for every notebook
    - session is responsible for launching kernels and handling requests and responses to the kernel
  - kernel is responsible for code cell execution
- provide save handler for notebooks
Missing pieces
- Currently all editors in the notebook is specially initialzied
  - It pretends to be in a diff editor (to disable a bunch of features)
  - No minimap, rulers, indent guides
  - No parameter hints, no bracket matching
  - I didn't get suggestion working, however Jupyter notebook extension sends completion request to @jupyterlab/services
- Since every code cell is a standalone monaco editor, there is no language features across cells, like suggestions from above code cells.
  - Technically it can be solved by registering a completion provider for Notebook cells' models.
- Debugging
- No rendering virtualization.

Common
- Performance is reasonable if Monaco Editor is optimized in both Web view and Core
- Language features require additional work for hooking up language server with code cell content
  - Jupyter notebook messages support Code Completion only at this moment
- Debugging support requires additional work as well
Python (running in webview)
- Cons
  - Keymaps
  - Extensions
- Pros
  - No work required in core
  - Highly customizable
ADS (running in core)
- Cons
  - require domain knowledge of Notebook
  - require content sanitization or using webview/iframes to prevent it from affecting the core
- Pros
  - editors work the same way as others
  - no additional cost for loading monaco editor and grammars, no trade for tokenization with webassembly
  - the UI/UX would be consistent

A jupyter notebook consists of cells and there are three major types of cells supported
- Code cell.
- Markdown cell.
- TextCell.
How a code cell is being executed
- See details