Formula Functions

werkbook ships with broad Excel formula coverage. The current community build supports more than 300 built-in functions across classic worksheet formulas, dynamic array functions, lookup helpers, financial functions, and lambda-style helpers.

This page is a high-level reference to the function families and the formula semantics that matter when using the library API. For programmatic discovery, run wb formula list.

Coverage Highlights

Representative functions from the current build:

Category	Representative functions
Math and trig	`ABS`, `ROUND`, `ROUNDUP`, `FLOOR`, `POWER`, `SEQUENCE`, `MMULT`, `MUNIT`
Statistical	`AVERAGE`, `COUNTIFS`, `MEDIAN`, `LARGE`, `SMALL`, `PERCENTILE`, `RANK.EQ`
Text	`TEXT`, `CONCAT`, `CONCATENATE`, `LEFT`, `MID`, `SEARCH`, `SUBSTITUTE`, `ROMAN`
Date and time	`DATE`, `DATEDIF`, `DATEVALUE`, `DAY`, `NETWORKDAYS`, `NOW`, `TODAY`
Lookup and reference	`INDEX`, `MATCH`, `XLOOKUP`, `FILTER`, `UNIQUE`, `CHOOSECOLS`, `DROP`
Logical and lambda	`IF`, `IFS`, `IFERROR`, `LET`, `LAMBDA`, `MAP`, `BYROW`, `BYCOL`, `SORT`
Financial	`PMT`, `PV`, `FV`, `NPV`, `IRR`, `RATE`, `CUMIPMT`, `SLN`
Engineering and info	`CONVERT`, `BIN2DEC`, `HEX2DEC`, `FORMULATEXT`, `ISFORMULA`, `ERROR.TYPE`

Modern Excel Features

The engine supports a useful subset of newer Excel behavior, including:

dynamic array functions such as FILTER, UNIQUE, SORT, SEQUENCE, HSTACK, and VSTACK
lambda-style helpers such as LET, LAMBDA, MAP, BYROW, and BYCOL
structured references against worksheet tables
defined names with workbook or sheet scope
cross-sheet references and whole-column references

Function Semantics in the Library

Formulas are stored without `=`

sheet.SetFormula("A1", "SUM(B1:B10)")

Results are lazy

Sheet.GetValue evaluates the formula on demand. Cell.Value() returns the cached cell payload and may not force recalculation.

Array results return the anchor-cell value through `GetValue`

If a formula spills an array, reading the formula cell through GetValue returns the top-left element of that result.

Errors come back as `werkbook.TypeError`

Typical values include #DIV/0!, #REF!, #VALUE!, #N/A, #SPILL!, and #CALC!.

Common Patterns

Conditional aggregation

SUMIFS(D2:D100, A2:A100, "West", B2:B100, ">0")

Modern lookup

XLOOKUP(A2, Products[SKU], Products[Price])

Named ranges

Revenue * TaxRate

Dynamic arrays

SORT(UNIQUE(FILTER(A2:A100, A2:A100<>"")))

Using the CLI

List all registered functions:

wb formula list