Compatibility
Formulon treats compatibility as something you can inspect and reproduce. Use this section when a workbook result differs from Excel, or when you want to understand which formulas and file features are implemented.
Compatibility is workload-specific
“Excel-compatible” does not mean every workbook behaves exactly like every Excel build. It means the documented profile, implemented function families, file-format support, and oracle tests match the workbook you plan to process.
To see how closely Formulon follows Excel in practice, start with How far compatibility goes: floating-point, date, coercion, locale and spill cases, each checked live against a value captured from Excel.
What to check
- Compare formulas against Formula coverage.
- Check workbook structures in File format support.
- Pin the target in Locale profiles, then check Text collation when comparisons, sorting, or lookup results matter.
- Review Error model so spreadsheet errors and host failures are handled separately.
Current status
Formulon remains pre-1.0. Of the 526 recognized names, 511 are real implementations, including the 2 environment-bound functions (CELL, INFO), and 15 are intentional unavailable service stubs. APIs can still change, so pin versions and keep a small workbook fixture set when results matter.
Coverage areas
| Area | What to check |
|---|---|
| Formula functions | Local implementation count, service stubs, and validation guidance in Formula coverage |
| Files | Read / write / preserve boundaries in File format support |
| Locale and language | The 28 profile IDs, locale facts, formula localization, and runtime editor links in Locale profiles and Workbook language |
| Text behavior | Mac measured collation, Windows word sort, and per-function strength in Text collation |
| Errors | #VALUE!, #REF!, parser failures, and host exceptions in Error model |
| Verification | Captured Excel values per profile, accepted divergences, and the closure checks in Oracle testing |