Chinese numeral parser

.gitignore

/.bundle/
/.yardoc
/Gemfile.lock
/_yardoc/
/coverage/
/doc/
/pkg/
/spec/reports/
/tmp/
*.bundle
*.so
*.o
*.a
mkmf.log

.rspec

--color

Gemfile

source 'https://rubygems.org'

gemspec

kansuji.gemspec

# coding: utf-8

Gem::Specification.new do |spec|
  spec.name          = 'kansuji'
  spec.version       = '0.0.1'
  spec.authors       = ['Kazuya Takeshima']
  spec.email         = ['[email protected]']
  spec.summary       = %q{Chinese numeral parser}
  spec.homepage      = 'https://gist.github.com/mitukiii/b3d9c496169baacc859d'
  spec.license       = 'MIT'

  spec.files         = `git ls-files`.split($/)
  spec.executables   = []
  spec.test_files    = ['kansuji_spec.rb']
  spec.require_paths = ['.']

  spec.add_runtime_dependency 'parslet'

  spec.add_development_dependency 'bundler', '~> 1.7'
end

kansuji.rb

# coding: utf-8

require 'parslet'

module Kansuji
  NUMBERS = %w{一 二 三 四 五 六 七 八 九}
  DIGITS  = %w{十 百 千}
  UNITS   = %w{万 億 兆 京 垓 𥝱 穣 溝 澗 正 載 極 恒河沙 阿僧祇 那由他 不可思議 無量大数}

  def self.parser
    @parser ||= Parser.new
  end

  def self.transform
    @transform ||= Transform.new
  end

  def self.parse(text)
    transform.apply(
      parser.parse(
        text
      )
    )
  end

  class Parser < Parslet::Parser
    root(:expressions)

    rule(:expressions) {
      (
        expression >> unit.maybe >> expressions.maybe |
        expression
      ).as(:expressions)
    }

    rule(:expression) {
      (
        number.maybe >> digit >> expression.maybe |
        number
      ).as(:expression)
    }

    rule(:number) {
      alternative_str(NUMBERS).as(:number)
    }

    rule(:digit) {
      alternative_str(DIGITS).as(:digit)
    }

    rule(:unit) {
      alternative_str(UNITS).as(:unit)
    }

    def alternative_str(values)
      values.map { |value|
        str(value)
      }.reduce { |alternatives, parslet|
        alternatives | parslet
      }
    end
  end

  class Transform < Parslet::Transform
    rule(expressions: simple(:expressions)) {
      expressions
    }

    rule(expression: simple(:expression)) {
      expression
    }

    rule(number: simple(:number)) {
      Number.new(number).to_i
    }

    rule(digit: simple(:digit)) {
      Digit.new(digit).to_i
    }

    rule(number: simple(:number), digit: simple(:digit)) {
      Number.new(number).to_i * Digit.new(digit).to_i
    }

    rule(digit: simple(:digit), expression: simple(:expression)) {
      Digit.new(digit).to_i + expression
    }

    rule(number: simple(:number), digit: simple(:digit), expression: simple(:expression)) {
      Number.new(number).to_i * Digit.new(digit).to_i + expression
    }

    rule(expression: simple(:expression), unit: simple(:unit)) {
      expression * Unit.new(unit).to_i
    }

    rule(expression: simple(:expression), unit: simple(:unit), expressions: simple(:expressions)) {
      expression * Unit.new(unit).to_i + expressions
    }
  end

  class Number < Struct.new(:number)
    def to_i
      NUMBERS.index(number) + 1
    end
  end

  class Digit < Struct.new(:digit)
    def to_i
      10 ** (DIGITS.index(digit) + 1)
    end
  end

  class Unit < Struct.new(:unit)
    def to_i
      10_000 ** (UNITS.index(unit) + 1)
    end
  end
end

kansuji_spec.rb

# coding: utf-8

lib = File.expand_path('../', __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)

require 'kansuji'

RSpec.describe Kansuji do
  describe '.parse' do
    {
      '一' => 1,

      '十' => 10,
      '十一' => 11,
      '二十' => 20,
      '二十一' => 21,

      '百一' => 101,
      '百十' => 110,
      '百十一' => 111,
      '百二十' => 120,
      '百二十一' => 121,
      '二百' => 200,

      '千一' => 1_001,
      '千十' => 1_010,
      '千十一' => 1_011,
      '千二十' => 1_020,
      '千二十一' => 1_021,
      '千百一' => 1_101,
      '千百十' => 1_110,
      '千百十一' => 1_111,
      '千百二十' => 1_120,
      '千百二十一' => 1_121,
      '二千' => 2_000,

      '一万一' => 10_001,
      '一万十' => 10_010,
      '一万十一' => 10_011,
      '一万二十' => 10_020,
      '一万二十一' => 10_021,
      '一万百一' => 10_101,
      '一万百十' => 10_110,
      '一万百十一' => 10_111,
      '一万百二十' => 10_120,
      '一万百二十一' => 10_121,
      '一万二百' => 10_200,
      '一万千一' => 11_001,
      '一万千十' => 11_010,
      '一万千十一' => 11_011,
      '一万千二十' => 11_020,
      '一万千二十一' => 11_021,
      '一万千百一' => 11_101,
      '一万千百十' => 11_110,
      '一万千百十一' => 11_111,
      '一万千百二十' => 11_120,
      '一万千百二十一' => 11_121,
      '一万二千' => 12_000,

      '十万' => 100_000,
      '二十万' => 200_000,
      '二十一万' => 210_000,

      '一億' => 100_000_000,
      '十億' => 1_000_000_000,
      '十一億' => 1_100_000_000,
      '二十億' => 2_000_000_000,
      '二十一億' => 2_100_000_000,
      '一兆' => 10 ** 12,
      '一京' => 10 ** 16,
      '一垓' => 10 ** 20,
      '一𥝱' => 10 ** 24,
      '一穣' => 10 ** 28,
      '一溝' => 10 ** 32,
      '一澗' => 10 ** 36,
      '一正' => 10 ** 40,
      '一載' => 10 ** 44,
      '一極' => 10 ** 48,
      '一恒河沙' => 10 ** 52,
      '一阿僧祇' => 10 ** 56,
      '一那由他' => 10 ** 60,
      '一不可思議' => 10 ** 64,
      '一無量大数' => 10 ** 68,
    }.each do |(text, number)|
      it ".parse(#{text.inspect}) = #{number.inspect}" do
        expect(Kansuji.parse(text)).to eql(number)
      end
    end

    context 'parse failed' do
      %w(万 一万億).each do |text|
        it ".parse(#{text.inspect}) should raise error" do
          expect { Kansuji.parse(text) }.to raise_error
        end
      end
    end
  end
end

Rakefile

ENV['gem_push'] = 'off'
ENV['SPEC'] = 'kansuji_spec.rb'

require 'bundler/gem_tasks'
require 'rspec/core/rake_task'

RSpec::Core::RakeTask.new

task default: :spec