initial import

LICENSE.txt

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+Copyright (c) 2011 invadersmustdie
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+## Arabiata - dead simple conversion of roman <> arabian numerals
+
+### Example
+
+        >> Arabiata.to_arabian("MC")
+        => 1100
+
+        >> Arabiata.to_roman(1100)
+        => "MC"

Rakefile

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+require 'rake/testtask'
+require 'rspec/core/rake_task'
+require 'rake/gempackagetask'
+
+require 'jeweler'
+Jeweler::Tasks.new do |gem|
+  gem.name = "arrabiata"
+  gem.homepage = "http://github.com/invadersmustdie/arrabiata"
+  gem.license = "MIT"
+  gem.summary = %Q{dead simple conversion of roman <> arabian numerals}
+  gem.description = %Q{dead simple conversion of roman <> arabian numerals}
+  gem.email = "rugek@dirtyhack.net"
+  gem.authors = ["invadersmustdie"]
+end
+Jeweler::RubygemsDotOrgTasks.new
+
+RSpec::Core::RakeTask.new(:spec) do |spec|
+  spec.pattern = 'spec/**/*_spec.rb'
+  spec.rspec_opts = ['--colour', '-f documentation', '--backtrace']
+end
+
+task :default => [:spec]

VERSION

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+0.1.0

arabiata.gemspec

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+# Generated by jeweler
+# DO NOT EDIT THIS FILE DIRECTLY
+# Instead, edit Jeweler::Tasks in Rakefile, and run 'rake gemspec'
+# -*- encoding: utf-8 -*-
+
+Gem::Specification.new do |s|
+  s.name = %q{arabiata}
+  s.version = "0.1.0"
+
+  s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
+  s.authors = ["invadersmustdie"]
+  s.date = %q{2011-01-20}
+  s.description = %q{dead simple conversion of roman <> arabian numerals}
+  s.email = %q{rugek@dirtyhack.net}
+  s.extra_rdoc_files = [
+    "LICENSE.txt",
+    "README.md"
+  ]
+  s.homepage = %q{http://github.com/invadersmustdie/arabiata}
+  s.licenses = ["MIT"]
+  s.require_paths = ["lib"]
+  s.rubygems_version = %q{1.3.7}
+  s.summary = %q{dead simple conversion of roman <> arabian numerals}
+
+  if s.respond_to? :specification_version then
+    current_version = Gem::Specification::CURRENT_SPECIFICATION_VERSION
+    s.specification_version = 3
+
+    if Gem::Version.new(Gem::VERSION) >= Gem::Version.new('1.2.0') then
+    else
+    end
+  else
+  end
+end
+

lib/arrabiata.rb

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+class Arrabiata
+  class ArrabiataError < StandardError; end
+  class NoZeroInRomanNumbers < ArrabiataError; end
+  class UnknownRomanNumberError < ArrabiataError; end
+
+  CONVERSION = {
+    "M" => 1000,
+    "D" => 500,
+    "C" => 100,
+    "L" => 50,
+    "X" => 10,
+    "V" => 5,
+    "I" => 1
+  }
+
+  def self.to_roman(n)
+    raise ArgumentError, "first argument is not a Fixnum" if !n.is_a?(Fixnum)
+    raise NoZeroInRomanNumbers, "roman numeral system doesn't include 0" if n == 0
+
+    result = ""
+
+    # NOTE: this version doesn't yet respects the subtractive principle
+    CONVERSION.sort_by { |d| d.last }.reverse.each do |k|
+      x = n / k.last
+      if x != 0
+        result << k.first * x
+        n = n - x * k.last
+      end
+    end
+
+    result
+  end
+
+  def self.to_arabian(str)
+    raise ArgumentError, "first argument is not a String" if !str.is_a?(String)
+
+    result = 0
+
+    str.scan(/\w/).each do |char|
+      raise UnknownRomanNumberError, "'#{char}' is not defined in roman numbers" if !CONVERSION[char]
+      result = result + CONVERSION[char]
+    end
+
+    result
+  end
+end

spec/arabiata_to_arabian_spec.rb

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+require "spec_helper"
+
+describe "Arrabiata -> to_arabian" do
+  it "should fail on characters not defined in roman numerals" do
+    lambda {
+      Arrabiata.to_arabian("MVVa")
+    }.should raise_error(Arrabiata::UnknownRomanNumberError, "'a' is not defined in roman numbers")
+  end
+
+  it "should fail on invalid argument passed" do
+    lambda {
+      Arrabiata.to_arabian(4.2)
+    }.should raise_error(ArgumentError, "first argument is not a String")
+  end
+
+  it "should convert III to 3" do
+    Arrabiata.to_arabian("III").should == 3
+  end
+
+  it "should convert VIII to 8" do
+    Arrabiata.to_arabian("VIII").should == 8
+  end
+
+  it "should convert M to 1000" do
+    Arrabiata.to_arabian("M").should == 1000
+  end
+
+  it "should convert MIII to 1003" do
+    Arrabiata.to_arabian("MIII").should == 1003
+  end
+
+  it "should convert MMDCCCLV to 2855 " do
+    Arrabiata.to_arabian("MMDCCCLV").should == 2855
+  end
+end

spec/arabiata_to_roman_spec.rb

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+require "spec_helper"
+
+describe "Arrabiata -> to_roman" do
+  it "should fail on 0 because its not included in roman numerals" do
+    lambda { 
+      Arrabiata.to_roman(0) 
+    }.should raise_error(Arrabiata::NoZeroInRomanNumbers, "roman numeral system doesn't include 0")
+  end
+
+  it "should fail on invalid argument passed" do
+    lambda {
+      Arrabiata.to_roman(4.2)
+    }.should raise_error(ArgumentError, "first argument is not a Fixnum")
+  end
+
+  it "should convert 3 to III" do
+    Arrabiata.to_roman(3).should == "III"
+  end
+
+  it "should convert 8 to VIII" do
+    Arrabiata.to_roman(8).should == "VIII"
+  end
+
+  it "should convert 1000 to M" do
+    Arrabiata.to_roman(1000).should == "M"
+  end
+
+  it "should convert 1003 to M" do
+    Arrabiata.to_roman(1003).should == "MIII"
+  end
+
+  it "should convert 2855 to MMDCCCLV" do
+    Arrabiata.to_roman(2855).should == "MMDCCCLV"
+  end
+end

spec/spec_helper.rb

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+require "arrabiata"