Formula Editor

The Formula Editor is the heart of Formula Foundry — a Monaco-based code editor tuned for spreadsheet formulas. It runs inside the Google Sheets add-on and the Excel add-in, and opens over whichever cell you’re working on.

What’s in the editor

The Editor window has four main areas:

• Tab bar at the top — one tab per formula you’re working on, each bound to a spreadsheet cell.
• Monaco editor in the middle — where you write the formula.
• Side rail on the right — quick access to AI Assistant, Custom Variables, and Snippets panels.
• Bottom toolbar — insert into cell, undo/redo, find, format, translator toggle, and editor options.

Tabs

Each tab holds one formula in flight. Tabs remember the cell they came from, their AI chat history, and the last formula text.

Right-click or use the tab menu to:

• Rename the tab — handy when juggling several formulas.
• Duplicate — clone the current tab to experiment without losing the original.
• Close, Close others, Close to the left, Close to the right.

The number of tabs you can have open at once depends on your plan’s maxOpenTabs quota. Starter caps it at 3; paid plans lift the cap.

Writing formulas

Syntax highlighting

Functions, operators, cell references, strings, and numbers are each color-coded through a Formula Foundry-branded Monaco theme. The theme swaps with your light/dark preference automatically.

Auto-complete

Monaco’s completion widget suggests function names as you type; accept with Tab or Enter. Type @@ to trigger completion for your custom variables in the current spreadsheet.

Live error checking

The parser runs on every keystroke. Anything it can’t parse is underlined; hover for a human-readable message.

Live preview

Below the editor, the Insert Formula Bar shows the formula exactly as it will be written into the cell after variable substitution and locale translation — so what you see is what the spreadsheet gets.

Keyboard shortcuts

The editor uses Monaco’s standard shortcuts.

The AI prompt box has its own keys: Enter to send, Shift + Enter for a newline, Escape to abort a streaming response.

Editor options

The toolbar opens a small preferences popover where you can toggle:

• Font size — stepper from small to large.
• Line numbers — on/off.
• Minimap — the overview strip on the right of Monaco.
• Show whitespace — render dots for spaces and arrows for tabs.

Your choices are remembered per device.

Formula translator

The translator converts a formula between Google Sheets and Excel dialects — handling commas vs. semicolons, function-name differences, and the subset of formulas that need structural changes (e.g. IFERROR variants).

Open the Translator from the bottom toolbar (marked Beta) and pick:

• Smart Fixes — rewrites that go beyond a name swap (locale separators, argument reshuffles).
• Function Names — maps between platform-specific names (e.g. ARRAYFORMULA ↔ Excel’s dynamic arrays).
• Syntax — the baseline comma/semicolon and reference-style conversion.

Switch target dialect with the Google Sheets / Microsoft Excel dropdown next to the Insert button; the formula is re-rendered on the fly.

Inserting into the spreadsheet

Click Insert in the bottom bar to write the current formula into the cell the tab is bound to. Formula Foundry substitutes your variables, applies the locale, and writes the result through the host adapter — same write path the spreadsheet would use for a formula typed directly.