Notebook Support

Zasper implements Jupyter’s wire protocol and reads and writes the .ipynb format directly, so notebooks move between Zasper and JupyterLab unchanged. It makes two guarantees:

• Saving creates no unwanted diff. When Zasper opens and saves a notebook, the file comes out byte-for-byte as Jupyter would have written it, so saving does not create merge conflicts.
• A notebook keeps its own nbformat version. A 4.2 notebook is saved as 4.2 rather than silently upgraded to the newest version, which is what JupyterLab does. Notebooks in formats 2 and 3 are converted to 4.5 when opened.

Saves are atomic: Zasper writes beside the file and then renames over it, so a crash or a full disk cannot leave a half-written notebook.

What Renders

The three missing types are worth knowing about before you run into them:

• text/latex is what SymPy produces after init_printing().
• image/svg+xml is what graphviz and networkx produce, and what matplotlib produces under %config InlineBackend.figure_format = 'svg'.
• image/jpeg covers display() of a JPEG.

Cells that produce these still run correctly; only the display is missing. These are the first things planned after 1.0.

Known Limitations

• Widget state is not saved in the notebook. If you reopen a notebook without a running kernel, widgets show a placeholder instead of their last state. Run the cell again to draw them.
• A cell’s output area ignores clear_output.
• Notebooks are not signed or trusted. Zasper does not yet implement Jupyter’s notebook trust system. Saved text/html output can contain scripts that run when the notebook is opened; that is how Plotly and Bokeh outputs draw themselves. Treat a notebook you did not write like any other downloaded file, and open one you don’t trust in protected mode.