nb-to-wolfbook

name	nb-to-wolfbook
description	Convert Mathematica .nb or .m files to Wolfbook .wb format so they open and run in VS Code. Use when bringing existing .nb/.m files into Wolfbook, or to make an existing .wb bridge-safe.

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 (bridge-safe + PUA→ASCII). /nb-to-wolfbook --fix-wb <file.wb> — normalize an EXISTING .wb in place (bridge-safe + PUA→ASCII), backup written. /nb-to-wolfbook --puafix <file.wb> — de-rectangle ONLY (PUA→ASCII, no newline reflow): the smallest diff that removes the rectangle glyphs from an already-bridge-safe .wb.

⚠️ 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.

The subtle case that slipped through once (the MMVbar regression)

MMVbar[...] := (-1)^(Total[j]+Length[j]) MMV[...] is one RowBox (the space is implicit Times), merely soft-wrapped for display in the .nb. The FE's "InputText" export ignores PageWidth (verified: Cell option, ExportPacket option, wrapping-Notebook option — all still wrap) and turns the wrap into a hard newline with a continuation indent: ... Length[j])\n MMV[...]. The line ends in ) — a complete value — so the old "does the line end in an operator?" heuristic said "statement boundary, keep the newline," and the MMV factor was dropped (MMVbar became a bare sign). This sat latent in the committed .wb/.nb for months.

The fix (in wl_normalize.normalize): a depth-0 newline followed by a continuation indent (spaces/tabs then more code, not a blank line) is a wrap → collapse to a space; genuine statement breaks export at column 0, so they are still kept. Backstop: find_split_hazards (CLI --check) flags any definition whose RHS is split across a top-level newline.

⚠️ The OTHER bug: PUA operators render as empty rectangles

Mathematica stores ==, ->, :> (and the constants I, E) as characters in the Unicode Private Use Area (\[Equal]=U+F431, \[Rule]=U+F522, \[RuleDelayed]=U+F51F, \[ImaginaryI]=U+F74E, \[ExponentialE]=U+F74D, \[LongEqual]=U+F7D9). The kernel parses them IDENTICALLY to the ASCII forms, and Mathematica's own fonts have glyphs for them — but the front-end "InputText" export keeps the literal PUA chars, so the .wb carries them too. A code font without the Wolfram PUA (VS Code's default, most monospace fonts) then draws each as an empty rectangle (tofu) — e.g. a cell's If[w == 1, If[k == 2, …]] showed as If[w ▯ 1, If[k ▯ 2, …]]. Nothing is broken; it is purely a display problem, but a confusing one.

The fix (in wl_normalize.pua_to_ascii, called first inside normalize): replace each PUA operator/constant with its ASCII equivalent (\[Equal]→==, \[Rule]→->, \[RuleDelayed]→:>, \[LongEqual]→==, \[ImaginaryI]→I, \[ExponentialE]→E). Kernel-identical, displays in any font. String-aware: PUA inside "..." string literals is left untouched (that is data, not code); PUA inside (* comments *) IS converted (display text, safe). Word-boundary-safe: the letter constants I/E get spaces inserted only when an adjacent alphanumeric would otherwise glue them into a different symbol (2\[ImaginaryI]→2 I, never 2I-as-something-else). Standard-Unicode operators that are NOT PUA (\[And]∧, \[Or]∨, \[LessEqual]≤, \[Element]∈, Greek letters ω/α/…) render fine and are deliberately left alone — converting them would be scope creep. Any PUA char with no ASCII mapping is reported (still a rectangle; decide by hand).

⚠️ Editing a .wb that is OPEN in VS Code: the live editor buffer overwrites on-disk edits, so a disk-level fix gets silently clobbered when the buffer next saves. Close the notebook tab (or edit via the Wolfbook MCP), THEN run the fix, THEN reopen.

Helper scripts (committed alongside this skill)

• wl_normalize.py — the normalizer. normalize(code) first runs pua_to_ascii (PUA operators → ASCII; see the rectangle bug above) then collapses intra-statement newlines (incl. FE soft-wraps via the continuation-indent signal); string/comment/bracket-aware. CLIs: python3 wl_normalize.py --wb <file.wb> rewrites every wolfram code cell in place (newline reflow + PUA→ASCII; writes <file>.wb.bak; warns on residual hazards/PUA); python3 wl_normalize.py --puafix <file.wb> does PUA→ASCII only (no reflow, minimal diff); python3 wl_normalize.py --check <file.wb> reports split-statement hazards AND any rectangle-rendering PUA chars (exit 1 if any). 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.
3. Normalize each code cell with wl_normalize.normalize (bridge-safety — non-negotiable).
4. 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

Run the checker (catches the )-suffix / implicit-Times split that a naive operator-suffix test misses — the MMVbar regression — AND reports any rectangle-rendering PUA chars left in code cells):

python3 .claude/skills/nb-to-wolfbook/wl_normalize.py --check "<file.wb>"
# expect: "OK: no split-statement hazards ..." and "OK: no PUA (rectangle) chars ..."  (exit 0)

The driver also prints any hazard inline. Output format: Converted: <src> -> <dst> (N code cells, M markdown cells, bridge-safe). If any file could not be converted, say which and why. A flagged hazard is usually a genuine split to fix; an occasional false positive is a real two-statement cell that lacks a ; separator — add the ; (or split into two cells) to clear it.