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.
What to check
- Compare formulas against Formula coverage.
- Check workbook structures in File format support.
- Review Error model so spreadsheet errors and host failures are handled separately.
Current status
Formulon is still pre-1.0 (currently 0.9.5). The function catalog is fully registered: of the 522 recognized names, 505 are unconditionally real local implementations, 2 more (CELL, INFO) also run locally but are environment-bound — some results depend on workbook or host state — and the remaining 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 |
| Errors | #VALUE!, #REF!, parser failures, and host exceptions in Error model |
| Status | Pre-1.0 APIs, 505 / 522 local function implementations, formula plus workbook oracle verification |