rbnf

This is a Go implementation of parts of ICU's spellout rules (RBNF) for numbers.

It's based on the "RBNF" part of the ICU project (http://site.icu-project.org/ and http://cldr.unicode.org/).

The license of the original software and data is here: https://github.com/unicode-org/icu/blob/master/icu4c/LICENSE http://www.unicode.org/copyright.html#License

The current spellout implementation does not use any of the original ICU code, but it supports most of the spellout rule format, and it can read the rule files, https://github.com/unicode-org/cldr/tree/master/common/rbnf.

Unsupported features

The following format strings are used in the ICU rules, but not fully supported by this package:

• last primary ignorable
• →→→

Experimental support

• Decimal format
  http://www.icu-project.org/applets/icu4j/4.1/docs-4_1_1/com/ibm/icu/text/DecimalFormat.html
• Singular/plural inflection forms (rules formulated as $(...)$)
  https://unicode.org/reports/tr35/tr35-numbers.html#Language_Plural_Rules

The rule sets have information on the public/private attribute, but the distinction is not supported on rule execution (all rules can be references as if they were public).

Command line tool

There is a command line program for expanding numbers according to a CLDR rule file.

Here's an example, using the English rules.

You need to have Go >= 1.12 installed.

Start by cloning the github.com/stts-se/rbnf repository, then:

cd rbnf/cmd/spellout/
go build

List the rules of the English rule file (reading the file directly from github):

 ./spellout -l https://raw.githubusercontent.com/unicode-org/cldr/master/common/rbnf/en.xml
 == Listing public rule sets ==
 SpelloutRules
  - spellout-cardinal [public] (38)
  - spellout-cardinal-verbose [public] (12)
  - spellout-numbering [public] (4)
  - spellout-numbering-verbose [public] (4)
  - spellout-numbering-year [public] (29)
  - spellout-ordinal [public] (30)
  - spellout-ordinal-verbose [public] (10)
  OrdinalRules
   - digits-ordinal [public] (1)

Or, download the rule file and save as en.xml:

   curl https://raw.githubusercontent.com/unicode-org/cldr/master/common/rbnf/en.xml > en.xml

Test the default cardinal rule expansion:

  ./spellout -r spellout-numbering en.xml 1066
  1066	one thousand sixty-six

Test spelling out as year:

  ./spellout -r spellout-numbering-year en.xml 1066
  1066	ten sixty-six

Test spelling out with standard in:

  echo 1066 | ./spellout -r spellout-numbering-year en.xml
  1066	ten sixty-six

Usage:

  ./spellout -h
  Usage: spellout <options> <xml file/url> <input>
    if no input argument is specified, input will be read from stdin
  Options:
    -L	List all (private/public) rules and exit (rule groups and rule sets)
    -d	Debug
    -g rule group
      	Use named rule group (default first group)
    -h	Print usage and exit
    -l	List public rules and exit (rule groups and rule sets)
    -r rule set
      	Use named rule set
    -s	Check rule file syntax and exit

Links and references

• ICU project and source code:
  http://site.icu-project.org/
  https://github.com/unicode-org/icu

• ICU user guide: http://userguide.icu-project.org/

• CLDR project and source code:
  http://cldr.unicode.org/
  https://github.com/unicode-org/cldr
  

• Rule format:
  http://userguide.icu-project.org/formatparse/numbers/rbnf-examples
  http://icu-project.org/apiref/icu4c/classRuleBasedNumberFormat.html
  http://www.icu-project.org/applets/icu4j/4.1/docs-4_1_1/com/ibm/icu/text/RuleBasedNumberFormat.html

• Rule files: https://github.com/unicode-org/cldr/tree/master/common/rbnf

• ICU license:
  http://www.unicode.org/copyright.html#License
  https://github.com/unicode-org/icu/blob/master/icu4c/LICENSE

  ---

  (There is a CLDR package in Go: https://godoc.org/golang.org/x/text/unicode/cldr)