World’s tiniest Roman ↔ Decimal number converter — ~1 KB, zero deps. Single-file, CLI included. Perfect for code-golf, minimal containers, or just for fun.

• ✅ int → ROMAN and ROMAN → int (case-insensitive)
• ✅ Standard subtractive forms: IV, IX, XL, XC, CD, CM
• ✅ Classic 1–3999 supported; >3999 continues with repeated M
• ✅ Zero dependencies, single tiny file
• ✅ CLI: nano-roman

# Local (from repo)
python app_min.py 3999   # MMMCMXCIX
python app_min.py XL     # 40

After installing:

# CLI
pip install nano-roman
nano-roman 1984   # -> MCMLXXXIV
nano-roman XLII   # -> 42
nano-roman mmxxv  # -> 2025

• Minimal token table (S and V) + greedy subtractive matching
• No heavy parsing/regex trees, no dependencies
• Single module + tiny CLI wrapper

• Convert the current year

(Get-Date -Format yyyy) | % { nano-roman $_ }   # 2025 -> MMXXV

date +%Y | xargs nano-roman                     # 2025 -> MMXXV

• “Roman clock” (hour only)

  (Get-Date -Format HH) | % { nano-roman $_ }     # 14 -> XIV

date +%I | xargs nano-roman                     # 07 -> VII

• Git tag in Roman

git tag "v$(nano-roman 2025)" && git push origin "v$(nano-roman 2025)"

• Batch convert a list

printf "4\n9\n42\n1999\n" | while read n; do nano-roman "$n"; done
# IV, IX, XLII, MCMXCIX

• Quick Windows alias

Set-Alias r nano-roman
r 3999   # -> MMMCMXCIX

Notes

• Classical Roman numerals have no zero and no negative values.
• For values >3999, this tool renders repeated M (ASCII extension). Classical notation would use overlines (vinculum) or parentheses ×1000.

MIT © 2025