Added plugin for converting non-Gregorian years

lib/DDG/Goodie/AltCalendars.pm

@@ -0,0 +1,48 @@
+package DDG::Goodie::AltCalendars;
+# ABSTRACT: Convert non-Gregorian years to the Gregorian calendar
+
+use DDG::Goodie;
+
+primary_example_queries 'heisei 24';
+secondary_example_queries 'meiji 1';
+description 'Convert non-Gregorian years to the Gregorian calendar';
+name 'Alternative Calendars';
+code_url 'https://github.com/duckduckgo/zeroclickinfo-goodies/blob/master/lib/DDG/Goodie/AltCalendars.pm';
+category 'conversions';
+topics 'everyday';
+
+attribution web => ['http://kyokodaniel.com/tech/', 'Daniel Davis'],
+            github => ['https://github.com/tagawa', 'tagawa'],
+            twitter => ['https://twitter.com/ourmaninjapan', 'ourmaninjapan'];
+
+triggers start => 'juche', 'minguo', 'meiji', 'taisho', 'taishou', 'showa', 'shouwa', 'heisei';
+
+zci answer_type => 'date_conversion';
+zci is_cached => 1;
+
+handle query_parts => sub {
+    return unless scalar(@_) == 2;
+    
+    my $year = $_[1];
+    if ($year =~ /\d*[1-9]\d*/) {
+        my $era = lc($_[0]);
+        my %eras = (
+            'meiji' => 1867, # Japanese Meiji era
+            'taisho' => 1911, # Japanese Taisho era
+            'taishou' => 1911, # Alternative spelling of "taisho"
+            'showa' => 1925, # Japanese Showa era
+            'shouwa' => 1925, # Alternative spelling of "showa"
+            'heisei' => 1988, # Japanese Heisei era
+            'juche' => 1911, # North Korean Juche era
+            'minguo' => 1911, # ROC (Taiwanese) Minguo era
+        );
+        
+        return unless exists $eras{$era};
+        
+        return $year + $eras{$era};
+    }
+
+    return ;
+};
+
+1;

t/AltCalendars.t

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+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use Test::More;
+use DDG::Test::Goodie;
+
+zci answer_type => 'date_conversion';
+zci is_cached => 1;
+
+ddg_goodie_test(
+        [qw(
+                DDG::Goodie::AltCalendars
+        )],
+        'heisei 25' => test_zci('2013'),
+        'shouwa 39' => test_zci('1964'),
+        'taisho 11' => test_zci('1922'),
+        'meiji 1' => test_zci('1868'),
+        'minguo 50' => test_zci('1961'),
+        'juche 07' => test_zci('1918'),
+);
+
+done_testing;