nb-to-wolfbook

Converts Mathematica files (.nb / .m) to Wolfbook .wb (a VS Code Notebook JSON), and — critically — makes the resulting cells bridge-safe so they evaluate identically through the Wolfbook MCP (runCell / evaluateExpression) as they do in the Mathematica front end.

When to invoke

/nb-to-wolfbook <file-or-directory> — convert .nb/.m to .wb. /nb-to-wolfbook --fix-wb <file.wb> — normalize an EXISTING .wb in place (bridge-safe), backup written.

⚠️ The bug this skill exists to prevent (READ THIS)

A Wolfram cell can wrap one statement over several physical lines:

Eeqv[{j1_},{k1_}] := (-1)^(j1) j1!/(k1-1) Coefficient[
   GenSer, ep[j1,k1]];
MMVbar[j_,k_] := (-1)^(Total[j]+Length[j])
   MMV[j,k];

The front end parses each cell as one unit, so this is fine interactively. But an evaluator that splits a cell on newlines (the Wolfbook MCP runCell, a headless Get of re-serialised text, naive ToExpression) sees broken fragments and either:

• throws Syntax::sntxi: Incomplete expression (the Sum[...,⏎{...}] case), or
• treats the newline as implicit `Times`: (-1)^k ⏎ MMV[...] silently drops to a

product / loses the MMV factor, and def1;⏎def2; becomes Times[def1;, def2;] instead of two definitions.

This corrupts the kernel silently — definitions look present but are wrong — and is exactly what makes a cell-by-cell rebuild "unfaithful." The fix: put each statement on one physical line, collapsing only the intra-statement newlines (insignificant whitespace) and keeping a newline only after a top-level ;. Semantics are unchanged, comments are preserved, and the cell is now safe for any evaluator.

Helper scripts (committed alongside this skill)

• wl_normalize.py — the normalizer. normalize(code) collapses intra-statement

newlines; string/comment/bracket-aware. Also a CLI: python3 wl_normalize.py --wb <file.wb> rewrites every wolfram code cell in place (writes <file>.wb.bak first). Or pipe: ... | python3 wl_normalize.py.

• nb2wb_extract.wls — wolframscript extractor: reads a .nb and emits every cell in

order as faithful InputText via the front end (FrontEndExportPacket[..., "InputText"]`), preserving comments and special characters. Avoids the old lossy "Package export + split on blank lines," which destroyed cell boundaries.

• nb2wb.py — the driver: runs the extractor, normalizes code cells, writes the .wb.

Steps for .nb files (preferred path — needs wolframscript)

python3 .claude/skills/nb-to-wolfbook/nb2wb.py "<file.nb>" ["<out.wb>"]

This produces a faithful, bridge-safe .wb. Report the printed summary line.

If wolframscript is unavailable, fall back to: open the notebook in Mathematica, File → Save As → Package (.m), then use the .m steps below — but STILL run the normalizer on the result (see below), or the multi-line bug persists.

Steps for .m files

1. Read the file.
2. Split into cells: runs of ≥2 blank lines are cell boundaries; a block that is only a

(* === Title === *)-style comment becomes a markdown cell, others are code cells.

1. Normalize each code cell with wl_normalize.normalize (bridge-safety — non-negotiable).
2. Write the .wb with json.dumps(notebook, indent=1, ensure_ascii=False).

.wb format reminders

• kind: 2 = wolfram code cell (set "languageId": "wolfram"), kind: 1 = markdown.
• 1-space indent; value a valid JSON string; outputs: []; UTF-8.
• Always build JSON with Python's json module, never by hand.

Making an existing .wb safe (no reconversion)

python3 .claude/skills/nb-to-wolfbook/wl_normalize.py --wb "numerics/your-notebook.wb"

Normalizes every code cell in place (backup .wb.bak). Use this when a .wb already exists but mis-evaluates through the bridge.

Verify after conversion

Confirm no code cell still has a mid-statement line break (the bridge-unsafe pattern):

def midline(v):  # any line ending in an operator / open bracket = continuation
    return any(l.rstrip().endswith(('+','-','*','/','/.','->',':>',',','**','(','[','{','=','^','@','/;','&&','||')) for l in v.split('\n'))
# expect 0 such code cells after normalize

Output format: Converted: <src> -> <dst> (N code cells, M markdown cells, bridge-safe). If any file could not be converted, say which and why.