xln — Excel names as code

xln shows an Excel workbook's defined names (line items, constants, LAMBDA functions) and the formulas of its named cells as text in VS Code. You read, search, check and edit them there, and xln writes the edits back into the .xlsx. It reads and writes the file itself: Excel does not need to be running, and nothing is installed in Excel.

It runs in desktop VS Code and in vscode.dev (Edge or Chrome, on a local folder), so it works on lab PCs where nothing can be installed.

Quick start

1. Pull. Open the folder that holds your workbook. Right-click model.xlsx in the Explorer → xln: Pull workbook. xln writes model.xln/ beside it: one .xln file per sheet under names/sheets/, and module files for LAMBDAs and other names.

2. Edit. Write formulas after the = of each name, as in Excel's formula bar:

   Sales @C3# = SEQUENCE(1, 5, 20000, 3400);
   COGS @C4# = Sales * 0.6;
   Gross_income @C5# = Sales - COGS;
   

   Completion offers names in scope and Excel functions; signature help shows LAMBDA parameters and their doc comments.

3. Check. Mistakes are underlined as you type: unknown names and functions, wrong argument counts, another sheet's local name read without its sheet. xln: Audit workbook reports checks C1–C15 on the whole workbook: functions stored without the prefix Excel needs (they show #NAME?), broken references, unused names, fixed references into spills, copy drift, cycles, labels that no longer match a renamed name.

4. Build. Right-click the .xln folder → xln: Build workbook. A dialog lists what will change; confirm, then open the workbook in Excel. On the desktop, xln: Build and reopen in Excel closes, writes and reopens it in one step.

Change layout and labels in Excel, save, and pull again; write formulas in xln and build. Edit one side at a time.

Also: a formula view of each sheet (names on cells, in order of appearance or of calculation), cell usages of a name, name search, Rename Symbol (F2) that also renames the name in the workbook's cell formulas on the next build, and a shared LAMBDA library with provenance (@from).

What xln never does

• No add-in, no macros. Nothing runs inside Excel.
• No hidden transformations. A pull writes the names as the workbook has them; a build writes only what you changed, and the dialog lists every change first. xln never renames a name or changes its scope on its own: the checker points at a problem, you make the edit.
• No silent overwrite. A desktop build stops while Excel has the file open, keeps the previous file as model.backup.xlsx, reads the result back and restores the original on a mismatch. A name or cell changed in both Excel and xln stops the build. In the browser the build writes a new file, model.xln.xlsx, and leaves yours alone.
• No cells or layout. xln does not add rows, move cells or write labels: Excel owns those.

Documentation

• User guide: install, the pull–edit–build loop on a small income statement, spills and #, scope, modules and LAMBDAs, the library, common messages, vscode.dev.
• The .xln language: the precise rules of the text format.
• For AFE (Excel Labs) users: the requests AFE users made, what xln does about each, and opening an AFE workbook with xln.
• Changelog.

Requirements

VS Code 1.110 or later, desktop (macOS, Windows) or vscode.dev in Edge or Chrome. Workbooks in .xlsx or .xlsm format.

Licence

MIT, © 2026 Luca Erzegovesi.