Formulas

Setting a formula and knowing its result are two different operations. A cell holds the formula text and a cached value, and they are stored separately in the file. SetFormulaRaw writes the text and clears the value, so nothing is computed and the cell reads as empty until something evaluates it. Excel recalculates when it opens a workbook, which is why a file with no cached values at all still looks correct on screen. Anything that reads the file without a formula engine, including a later UniOffice program, sees the blank.

Evaluation is what fills those values in. Workbook.RecalculateFormulas runs UniOffice’s own engine over every sheet and writes the result of each formula back as its cached value, leaving the formulas in place. A formula.Evaluator does the same work for one expression at a time and hands the result back to your program instead of to the file. The engine implements 231 functions and an incomplete grammar; anything it cannot compute, including a function it does not know, leaves the cached value empty rather than writing an error, so Excel recovers on open.

Flattening goes further and is not a variant of evaluating. It clears each cell and writes the computed value as the cell’s own value, so the formulas are gone from the saved file. That is what you want for a report nobody should re-run, and it is a trap for a workbook using functions the engine lacks, because those flatten to a permanent #VALUE!.

Shared formulas are a size optimization, not a different semantics. One definition covers a rectangular block, with relative references offset per cell and $ suppressing the offset, exactly as filling a formula down a column in Excel does. The file gets smaller and Excel reads it identically.

The last three guides are about referring to cells rather than computing with them: parsing a reference string into its parts, placing a cell in a specific column, and giving a range a name that formulas and chart series can use.

Where to look