Unicode RBNF

A pure Python implementation of rule based number formatting (RBNF) using the Unicode Common Locale Data Repository (CLDR).

This lets you spell out numbers for a large number of locales:

from unicode_rbnf import RbnfEngine

engine = RbnfEngine.for_language("en")
assert engine.format_number(1234) == "one thousand two hundred thirty-four"

Depending on the locale, different rulesets are supported as well:

from unicode_rbnf import RbnfEngine, RulesetName

engine = RbnfEngine.for_language("en")
assert engine.format_number(1999, RulesetName.YEAR) == "nineteen ninety-nine"
assert engine.format_number(11, RulesetName.ORDINAL) == "eleventh"

Supported locales

See: https://github.com/unicode-org/cldr/tree/release-44/common/rbnf

Engine implementation

Not all features of the RBNF engine are implemented. The following features are available:

• Literal text (hundred)
• Quotient substitution (<< or ←←)
• Reminder substitution (>> or →→)
• Optional substitution ([...])
• Rule substituton (←%ruleset_name←)
• Rule replacement (=%ruleset_name=)
• Special rules:
  • Negative numbers (-x)
  • Improper fractions (x.x)
  • Not a number (NaN)
  • Infinity (Inf)

Some features that will need to be added eventually:

• Proper fraction rules (0.x)
• Preceding reminder substitution (>>> or →→→)
• Number format strings (==)