diff --git a/.github/workflows/build-ruby.yml b/.github/workflows/build-ruby.yml
new file mode 100644
index 0000000..db4afc0
--- /dev/null
+++ b/.github/workflows/build-ruby.yml
@@ -0,0 +1,22 @@
+name: Ruby
+
+on:
+  push:
+    tags: ['*']
+  pull_request:
+    branches: [main]
+    paths:
+    - 'ruby/**/*'
+    - 'uklatn.gemspec'
+
+jobs:
+
+  build-ruby:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Test
+      working-directory: ${{github.workspace}}/ruby
+      run: make test
diff --git a/.gitignore b/.gitignore
index dd92a00..9709d73 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,4 +9,4 @@ __pycache__/
 *.egg-info/
 *.so
 .swiftpm/
-
+*.gem
diff --git a/ruby/Makefile b/ruby/Makefile
new file mode 100644
index 0000000..867ee25
--- /dev/null
+++ b/ruby/Makefile
@@ -0,0 +1,10 @@
+.PHONY: build
+.PHONY: test
+
+all: test
+
+build:
+	@gem build uklatn.gemspec
+
+test:
+	@ruby test/uklatn/test_uklatn.rb
diff --git a/ruby/lib/uklatn.rb b/ruby/lib/uklatn.rb
new file mode 100644
index 0000000..c372743
--- /dev/null
+++ b/ruby/lib/uklatn.rb
@@ -0,0 +1,172 @@
+# Generated by gentables.py, do not edit.
+
+# Ukrainian Cyrillic transliteration to and from Latin script.
+#
+# Tables:
+# - 'DSTU_9112_A': DSTU 9112:2021 System A
+# - 'DSTU_9112_B': DSTU 9112:2021 System B
+# - 'KMU_55': KMU 55:2010, not reversible
+class UkrainianLatin
+
+    # Transliterates a string of Ukrainian Cyrillic to Latin script.
+    def encode(text, table = 'DSTU_9112_A')
+        tr = TABLES[table][0]
+        return tr.transform(text) if tr
+        raise ArgumentError.new("invalid table #{table}")
+    end
+
+    # Re-transliterates a string of Ukrainian Latin to Cyrillic script.
+    def decode(text, table = 'DSTU_9112_A')
+        tr = TABLES[table][1]
+        return tr.transform(text) if tr
+        raise ArgumentError.new("invalid table #{table}")
+    end
+
+    class Uklatn_uk_uk_Latn_DSTU_9112_A # :nodoc:
+        def initialize()
+            @rx1 = /\b([Ьь])|([Ьь](?=[АаЕеУу])|[ЄЮЯ](?=\u0301?[а-щьюяєіїґ’])|(?<=[Б-ДЖЗК-НП-ТФ-Щб-джзк-нп-тф-щҐґ])[Йй])|([ЁЄІЇЎА-яёєіїўҐґ’])/
+            @maps1 = [
+                {"Ь"=>"Ĵ","ь"=>"ĵ"},
+                {"Ь"=>"J'","ь"=>"j'","Є"=>"Je","Ю"=>"Ju","Я"=>"Ja","Й"=>"'J","й"=>"'j"},
+                {"А"=>"A","а"=>"a","Б"=>"B","б"=>"b","В"=>"V","в"=>"v","Г"=>"Ğ","г"=>"ğ","Ґ"=>"G","ґ"=>"g","Д"=>"D","д"=>"d","Е"=>"E","е"=>"e","Є"=>"JE","є"=>"je","Ж"=>"Ž","ж"=>"ž","З"=>"Z","з"=>"z","И"=>"Y","и"=>"y","І"=>"I","і"=>"i","Ї"=>"Ï","ї"=>"ï","К"=>"K","к"=>"k","Л"=>"L","л"=>"l","М"=>"M","м"=>"m","Н"=>"N","н"=>"n","О"=>"O","о"=>"o","П"=>"P","п"=>"p","Р"=>"R","р"=>"r","С"=>"S","с"=>"s","Т"=>"T","т"=>"t","У"=>"U","у"=>"u","Ф"=>"F","ф"=>"f","Х"=>"X","х"=>"x","Ц"=>"C","ц"=>"c","Ч"=>"Č","ч"=>"č","Ш"=>"Š","ш"=>"š","Щ"=>"Ŝ","щ"=>"ŝ","Ю"=>"JU","ю"=>"ju","Я"=>"JA","я"=>"ja","Ь"=>"J","ь"=>"j","Й"=>"J","й"=>"j","’"=>"'","Ё"=>"Ö","ё"=>"ö","Ў"=>"Ŭ","ў"=>"ŭ","Ъ"=>"Ǒ","ъ"=>"ǒ","Ы"=>"Ȳ","ы"=>"ȳ","Э"=>"Ē","э"=>"ē"},
+            ]
+        end
+
+        def transform(text)
+            text = text.unicode_normalize(:nfc)
+            text = text.gsub(@rx1) do |m|
+                next @maps1[2].fetch($3, $3) unless $3.nil?
+                next @maps1[1].fetch($2, $2) unless $2.nil?
+                next @maps1[0].fetch($1, $1) unless $1.nil?
+                m
+            end
+            text = text.unicode_normalize(:nfc)
+        end
+    end
+
+    class Uklatn_uk_uk_Latn_DSTU_9112_B # :nodoc:
+        def initialize()
+            @rx1 = /([Ьь](?=[АаЕеІіУу])|(?<=[Б-ДЖЗК-НП-ТФ-Щб-джзк-нп-тф-щҐґ])[Йй])|([ГЄЖЇХЩШЧЮЯЁЎЪЫЭ](?=\u0301?[а-яёєіїўґ’])|\b[Ьь])|([ЁЄІЇЎА-яёєіїўҐґ’])/
+            @maps1 = [
+                {"Ь"=>"J'","ь"=>"j'","Й"=>"'J","й"=>"'j"},
+                {"Г"=>"Gh","Є"=>"Je","Ж"=>"Zh","Ї"=>"Ji","Х"=>"Kh","Щ"=>"Shch","Ш"=>"Sh","Ч"=>"Ch","Ю"=>"Ju","Я"=>"Ja","Ё"=>"Jow","Ў"=>"Uh","Ъ"=>"Oh","Ы"=>"Yw","Э"=>"Ehw","Ь"=>"Hj","ь"=>"hj"},
+                {"А"=>"A","а"=>"a","Б"=>"B","б"=>"b","В"=>"V","в"=>"v","Г"=>"GH","г"=>"gh","Ґ"=>"G","ґ"=>"g","Д"=>"D","д"=>"d","Е"=>"E","е"=>"e","Є"=>"JE","є"=>"je","Ж"=>"ZH","ж"=>"zh","З"=>"Z","з"=>"z","И"=>"Y","и"=>"y","І"=>"I","і"=>"i","Ї"=>"JI","ї"=>"ji","Х"=>"KH","х"=>"kh","К"=>"K","к"=>"k","Л"=>"L","л"=>"l","М"=>"M","м"=>"m","Н"=>"N","н"=>"n","О"=>"O","о"=>"o","П"=>"P","п"=>"p","Р"=>"R","р"=>"r","Щ"=>"SHCH","щ"=>"shch","Ш"=>"SH","ш"=>"sh","С"=>"S","с"=>"s","Т"=>"T","т"=>"t","У"=>"U","у"=>"u","Ф"=>"F","ф"=>"f","Ч"=>"CH","ч"=>"ch","Ц"=>"C","ц"=>"c","Ю"=>"JU","ю"=>"ju","Я"=>"JA","я"=>"ja","Й"=>"J","й"=>"j","Ь"=>"J","ь"=>"j","’"=>"'","Ё"=>"JOW","ё"=>"jow","Ў"=>"UH","ў"=>"uh","Ъ"=>"OH","ъ"=>"oh","Ы"=>"YW","ы"=>"yw","Э"=>"EHW","э"=>"ehw"},
+            ]
+        end
+
+        def transform(text)
+            text = text.unicode_normalize(:nfc)
+            text = text.gsub(@rx1) do |m|
+                next @maps1[2].fetch($3, $3) unless $3.nil?
+                next @maps1[1].fetch($2, $2) unless $2.nil?
+                next @maps1[0].fetch($1, $1) unless $1.nil?
+                m
+            end
+            text = text.unicode_normalize(:nfc)
+        end
+    end
+
+    class Uklatn_uk_uk_Latn_KMU_55 # :nodoc:
+        def initialize()
+            @rx1 = /(?<=[ЁЄІЇЎА-яёєіїўҐґ])([’\u0027])(?=[ЁЄІЇЎА-яёєіїўҐґ])/
+            @maps1 = [
+                {"’"=>"","'"=>""},
+            ]
+            @rx2 = /\b([ЄЇЮЯ])(?=\u0301?[а-яёєіїўґ’])|\b([ЙйЄЇЮЯєїюя])|([Зз]Г|[ЖХЦЩШЧЄЇЮЯ])(?=\u0301?[а-яёєіїўґ’])|([Зз][Гг]|[ЄІЇА-ЩЬЮ-щьюяєіїҐґ’])/
+            @maps2 = [
+                {"Є"=>"Ye","Ї"=>"Yi","Ю"=>"Yu","Я"=>"Ya"},
+                {"Й"=>"Y","й"=>"y","Є"=>"YE","є"=>"ye","Ї"=>"YI","ї"=>"yi","Ю"=>"YU","ю"=>"yu","Я"=>"YA","я"=>"ya"},
+                {"ЗГ"=>"ZGh","зГ"=>"zGh","Ж"=>"Zh","Х"=>"Kh","Ц"=>"Ts","Щ"=>"Shch","Ш"=>"Sh","Ч"=>"Ch","Є"=>"Ie","Ї"=>"I","Ю"=>"Iu","Я"=>"Ia"},
+                {"ЗГ"=>"ZGH","Зг"=>"Zgh","зГ"=>"zGH","зг"=>"zgh","А"=>"A","а"=>"a","Б"=>"B","б"=>"b","В"=>"V","в"=>"v","Г"=>"H","г"=>"h","Ґ"=>"G","ґ"=>"g","Д"=>"D","д"=>"d","Е"=>"E","е"=>"e","Є"=>"IE","є"=>"ie","Ж"=>"ZH","ж"=>"zh","З"=>"Z","з"=>"z","И"=>"Y","и"=>"y","І"=>"I","і"=>"i","Ї"=>"I","ї"=>"i","Х"=>"KH","х"=>"kh","К"=>"K","к"=>"k","Л"=>"L","л"=>"l","М"=>"M","м"=>"m","Н"=>"N","н"=>"n","О"=>"O","о"=>"o","П"=>"P","п"=>"p","Р"=>"R","р"=>"r","Щ"=>"SHCH","щ"=>"shch","Ш"=>"SH","ш"=>"sh","С"=>"S","с"=>"s","Т"=>"T","т"=>"t","У"=>"U","у"=>"u","Ф"=>"F","ф"=>"f","Ч"=>"CH","ч"=>"ch","Ц"=>"TS","ц"=>"ts","Ю"=>"IU","ю"=>"iu","Я"=>"IA","я"=>"ia","Й"=>"I","й"=>"i","Ь"=>"","ь"=>"","’"=>""},
+            ]
+        end
+
+        def transform(text)
+            text = text.unicode_normalize(:nfc)
+            text = text.gsub(@rx1) do |m|
+                next @maps1[0].fetch($1, $1) unless $1.nil?
+                m
+            end
+            text = text.gsub(@rx2) do |m|
+                next @maps2[3].fetch($4, $4) unless $4.nil?
+                next @maps2[2].fetch($3, $3) unless $3.nil?
+                next @maps2[1].fetch($2, $2) unless $2.nil?
+                next @maps2[0].fetch($1, $1) unless $1.nil?
+                m
+            end
+            text = text.unicode_normalize(:nfc)
+        end
+    end
+
+    class Uklatn_uk_Latn_DSTU_9112_A_uk # :nodoc:
+        def initialize()
+            @rx1 = /([ÁáÉéÍíÓóÚúÝýḮḯ])/
+            @maps1 = [
+                {"Á"=>"Á","á"=>"á","É"=>"É","é"=>"é","Í"=>"Í","í"=>"í","Ó"=>"Ó","ó"=>"ó","Ú"=>"Ú","ú"=>"ú","Ý"=>"Ý","ý"=>"ý","Ḯ"=>"Ḯ","ḯ"=>"ḯ"},
+            ]
+            @rx2 = /(J[Ee]|j[Ee]|J[Uu]|j[Uu]|J[Aa]|j[Aa]|[A-GIK-PR-VXYZa-gik-pr-vxyzÏÖïöČčĒēĞğĴĵŜŝŠšŬŭŽžǑǒȲȳ])|(?<=[BbCcDdFfGgKkLlMmNnPpRrSsTtVvXxZzČčĞğŜŝŠšŽž])([Jj]\u0027(?=[AaEeUu])|[Jj])|(\u0027[Jj](?![AaEeIiUu])|\u0027(?=[Jj])|[Jj])/
+            @maps2 = [
+                {"A"=>"А","a"=>"а","B"=>"Б","b"=>"б","V"=>"В","v"=>"в","Ğ"=>"Г","ğ"=>"г","G"=>"Ґ","g"=>"ґ","D"=>"Д","d"=>"д","E"=>"Е","e"=>"е","JE"=>"Є","Je"=>"Є","jE"=>"є","je"=>"є","Ž"=>"Ж","ž"=>"ж","Z"=>"З","z"=>"з","Y"=>"И","y"=>"и","I"=>"І","i"=>"і","Ï"=>"Ї","ï"=>"ї","K"=>"К","k"=>"к","L"=>"Л","l"=>"л","M"=>"М","m"=>"м","N"=>"Н","n"=>"н","O"=>"О","o"=>"о","P"=>"П","p"=>"п","R"=>"Р","r"=>"р","S"=>"С","s"=>"с","T"=>"Т","t"=>"т","U"=>"У","u"=>"у","F"=>"Ф","f"=>"ф","X"=>"Х","x"=>"х","C"=>"Ц","c"=>"ц","Č"=>"Ч","č"=>"ч","Š"=>"Ш","š"=>"ш","Ŝ"=>"Щ","ŝ"=>"щ","JU"=>"Ю","Ju"=>"Ю","jU"=>"ю","ju"=>"ю","JA"=>"Я","Ja"=>"Я","jA"=>"я","ja"=>"я","Ĵ"=>"Ь","ĵ"=>"ь","Ö"=>"Ё","ö"=>"ё","Ŭ"=>"Ў","ŭ"=>"ў","Ǒ"=>"Ъ","ǒ"=>"ъ","Ȳ"=>"Ы","ȳ"=>"ы","Ē"=>"Э","ē"=>"э"},
+                {"J"=>"Ь","j"=>"ь","J'"=>"Ь","j'"=>"ь"},
+                {"'J"=>"Й","'j"=>"й","'"=>"’","J"=>"Й","j"=>"й"},
+            ]
+        end
+
+        def transform(text)
+            text = text.unicode_normalize(:nfc)
+            text = text.gsub(@rx1) do |m|
+                next @maps1[0].fetch($1, $1) unless $1.nil?
+                m
+            end
+            text = text.gsub(@rx2) do |m|
+                next @maps2[2].fetch($3, $3) unless $3.nil?
+                next @maps2[1].fetch($2, $2) unless $2.nil?
+                next @maps2[0].fetch($1, $1) unless $1.nil?
+                m
+            end
+            text = text.unicode_normalize(:nfc)
+        end
+    end
+
+    class Uklatn_uk_Latn_DSTU_9112_B_uk # :nodoc:
+        def initialize()
+            @rx1 = /([ÁáÉéÍíÓóÚúÝý])/
+            @maps1 = [
+                {"Á"=>"Á","á"=>"á","É"=>"É","é"=>"é","Í"=>"Í","í"=>"í","Ó"=>"Ó","ó"=>"ó","Ú"=>"Ú","ú"=>"ú","Ý"=>"Ý","ý"=>"ý"},
+            ]
+            @rx2 = /([Jj][Oo][Ww]|[Ss][Hh][Cc][Hh]|[CcGgKkSsZzUuOo][Hh]|[Yy][Ww]|[Ee][Hh][Ww]|[Jj][EeIiUuAa]|[Hh][Jj]|[A-GIK-PR-VYZa-gik-pr-vyz])|(?<=[Ss][Hh][Cc][Hh])([Jj]\u0027(?=[AaEeIiUu])|[Jj])|(?<=[CcGgKkSsZz][Hh])([Jj]\u0027(?=[AaEeIiUu])|[Jj])|(?<=[BCDFGKLMNPRSTVZbcdfgklmnprstvzv])([Jj]\u0027(?=[AaEeIiUu])|[Jj])|(\u0027[Jj](?![AaEeIiUu])|\u0027(?=[Jj])|[Jj])/
+            @maps2 = [
+                {"A"=>"А","a"=>"а","B"=>"Б","b"=>"б","V"=>"В","v"=>"в","GH"=>"Г","Gh"=>"Г","gH"=>"г","gh"=>"г","G"=>"Ґ","g"=>"ґ","D"=>"Д","d"=>"д","E"=>"Е","e"=>"е","JE"=>"Є","Je"=>"Є","jE"=>"є","je"=>"є","ZH"=>"Ж","Zh"=>"Ж","zH"=>"ж","zh"=>"ж","Z"=>"З","z"=>"з","Y"=>"И","y"=>"и","I"=>"І","i"=>"і","JI"=>"Ї","Ji"=>"Ї","jI"=>"ї","ji"=>"ї","KH"=>"Х","Kh"=>"Х","kH"=>"х","kh"=>"х","K"=>"К","k"=>"к","L"=>"Л","l"=>"л","M"=>"М","m"=>"м","N"=>"Н","n"=>"н","O"=>"О","o"=>"о","P"=>"П","p"=>"п","R"=>"Р","r"=>"р","SHCH"=>"Щ","SHCh"=>"Щ","SHcH"=>"Щ","SHch"=>"Щ","ShCH"=>"Щ","ShCh"=>"Щ","ShcH"=>"Щ","Shch"=>"Щ","sHCH"=>"щ","sHCh"=>"щ","sHcH"=>"щ","sHch"=>"щ","shCH"=>"щ","shCh"=>"щ","shcH"=>"щ","shch"=>"щ","SH"=>"Ш","Sh"=>"Ш","sH"=>"ш","sh"=>"ш","S"=>"С","s"=>"с","T"=>"Т","t"=>"т","U"=>"У","u"=>"у","F"=>"Ф","f"=>"ф","CH"=>"Ч","Ch"=>"Ч","cH"=>"ч","ch"=>"ч","C"=>"Ц","c"=>"ц","JU"=>"Ю","Ju"=>"Ю","jU"=>"ю","ju"=>"ю","JA"=>"Я","Ja"=>"Я","jA"=>"я","ja"=>"я","HJ"=>"Ь","Hj"=>"Ь","hJ"=>"ь","hj"=>"ь","JOW"=>"Ё","JOw"=>"Ё","JoW"=>"Ё","Jow"=>"Ё","jOW"=>"ё","jOw"=>"ё","joW"=>"ё","jow"=>"ё","UH"=>"Ў","Uh"=>"Ў","uH"=>"ў","uh"=>"ў","OH"=>"Ъ","Oh"=>"Ъ","oH"=>"ъ","oh"=>"ъ","YW"=>"Ы","Yw"=>"Ы","yW"=>"ы","yw"=>"ы","EHW"=>"Э","EHw"=>"Э","EhW"=>"Э","Ehw"=>"Э","eHW"=>"э","eHw"=>"э","ehW"=>"э","ehw"=>"э"},
+                {"J"=>"Ь","j"=>"ь","J'"=>"Ь","j'"=>"ь"},
+                {"J"=>"Ь","j"=>"ь","J'"=>"Ь","j'"=>"ь"},
+                {"J"=>"Ь","j"=>"ь","J'"=>"Ь","j'"=>"ь"},
+                {"'J"=>"Й","'j"=>"й","'"=>"’","J"=>"Й","j"=>"й"},
+            ]
+        end
+
+        def transform(text)
+            text = text.unicode_normalize(:nfc)
+            text = text.gsub(@rx1) do |m|
+                next @maps1[0].fetch($1, $1) unless $1.nil?
+                m
+            end
+            text = text.gsub(@rx2) do |m|
+                next @maps2[4].fetch($5, $5) unless $5.nil?
+                next @maps2[3].fetch($4, $4) unless $4.nil?
+                next @maps2[2].fetch($3, $3) unless $3.nil?
+                next @maps2[1].fetch($2, $2) unless $2.nil?
+                next @maps2[0].fetch($1, $1) unless $1.nil?
+                m
+            end
+            text = text.unicode_normalize(:nfc)
+        end
+    end
+
+    TABLES = Hash.new([nil, nil]) # :nodoc:
+    TABLES['DSTU_9112_A'] = [Uklatn_uk_uk_Latn_DSTU_9112_A.new(), Uklatn_uk_Latn_DSTU_9112_A_uk.new()]
+    TABLES['DSTU-9112-A'] = TABLES['DSTU_9112_A']
+    TABLES['DSTU_9112_B'] = [Uklatn_uk_uk_Latn_DSTU_9112_B.new(), Uklatn_uk_Latn_DSTU_9112_B_uk.new()]
+    TABLES['DSTU-9112-B'] = TABLES['DSTU_9112_B']
+    TABLES['KMU_55'] = [Uklatn_uk_uk_Latn_KMU_55.new(), nil]
+    TABLES['KMU-55'] = TABLES['KMU_55']
+end
diff --git a/ruby/test/uklatn/test_uklatn.rb b/ruby/test/uklatn/test_uklatn.rb
new file mode 100644
index 0000000..1ab62ac
--- /dev/null
+++ b/ruby/test/uklatn/test_uklatn.rb
@@ -0,0 +1,346 @@
+# Generated by gentests.py, do not edit.
+
+require_relative '../../lib/uklatn.rb'
+
+class TestUkrainianLatin # :nodoc:
+
+    def initialize
+        @tr = UkrainianLatin.new
+    end
+
+    def assert_equal(expect, actual, input)
+        if expect != actual
+            s = actual.chars
+            arr = expect.chars.map {|c| c == s.shift ? ' ' : '^'}.join
+            raise "failed\n input: #{input}\nexpect: #{expect}\nactual: #{actual}\n        #{arr}"
+        end
+    end
+
+    def test_DSTU_9112_A()
+
+        data_c2lr = [
+        [
+            "Україна, Хмельницький",
+            "Ukraïna, Xmeljnycjkyj"
+        ],
+        [
+            "Щастям б’єш жук їх глицю в фон й ґедзь пріч.",
+            "Ŝastjam b'ješ žuk ïx ğlycju v fon j gedzj prič."
+        ],
+        [
+            "ь Ь ль льє льї лью лья лье льі льу льа льйо льо",
+            "ĵ Ĵ lj ljje ljï ljju ljja lj'e lji lj'u lj'a ljjo ljo"
+        ],
+        [
+            "Єл Їл Юл Ял",
+            "Jel Ïl Jul Jal"
+        ],
+        [
+            "бь вь гь ґь дь жь зь кь ль мь нь пь рь сь ть фь хь ць чь шь щь",
+            "bj vj ğj gj dj žj zj kj lj mj nj pj rj sj tj fj xj cj čj šj ŝj"
+        ],
+        [
+            "бя вя гя ґя дя жя зя кя ля мя ня пя ря ся тя фя хя ця чя шя щя",
+            "bja vja ğja gja dja žja zja kja lja mja nja pja rja sja tja fja xja cja čja šja ŝja"
+        ],
+        [
+            "б’я в’я г’я ґ’я д’я ж’я з’я к’я л’я м’я н’я п’я р’я с’я т’я ф’я х’я ц’я ч’я ш’я щ’я",
+            "b'ja v'ja ğ'ja g'ja d'ja ž'ja z'ja k'ja l'ja m'ja n'ja p'ja r'ja s'ja t'ja f'ja x'ja c'ja č'ja š'ja ŝ'ja"
+        ],
+        [
+            "бй бйо вй гй ґй дй жй зй кй лй мй нй пй рй сй тй фй хй цй чй шй щй",
+            "b'j b'jo v'j ğ'j g'j d'j ž'j z'j k'j l'j m'j n'j p'j r'j s'j t'j f'j x'j c'j č'j š'j ŝ'j"
+        ],
+        [
+            "ня ньа н’я нь'н ньн",
+            "nja nj'a n'ja nj'n njn"
+        ],
+        [
+            "рос дыня эзёдынъ. бр кроў.",
+            "ros dȳnja ēzödȳnǒ. br kroŭ."
+        ],
+        [
+            "А́ а́ Е́ е́ Є́ є́ И́ и́ І́ і́ Ї́ ї́ О́ о́ У́ у́ Ю́ ю́ Я́ я́",
+            "Á á É é JÉ jé Ý ý Í í Ḯ ḯ Ó ó Ú ú JÚ jú JÁ já"
+        ],
+        [
+            "Є́с сЄ́с є́с сє́с Ї́с сЇ́с ї́с сї́с Ю́с сЮ́с ю́с сю́с Я́с сЯ́с я́с ся́с",
+            "Jés sJés jés sjés Ḯs sḮs ḯs sḯs Jús sJús jús sjús Jás sJás jás sjás"
+        ],
+        [
+            "' ім’я 'жук' \"жук\" ' '",
+            "' im'ja 'žuk' \"žuk\" ' '"
+        ],
+        [
+            "Сонце світить майже білим світлом, однак через сильніше розсіювання і поглинання короткохвильової частини спектра атмосферою Землі пряме світло Сонця біля поверхні нашої планети набуває певного жовтого відтінку. Якщо небо ясне, то блакитний відтінок розсіяного світла складається з жовтуватим прямим сонячним світлом і загальне освітлення об’єктів на Землі стає білим.",
+            "Sonce svitytj majže bilym svitlom, odnak čerez syljniše rozsijuvannja i poğlynannja korotkoxvyljovoï častyny spektra atmosferoju Zemli prjame svitlo Soncja bilja poverxni našoï planety nabuvaje pevnoğo žovtoğo vidtinku. Jakŝo nebo jasne, to blakytnyj vidtinok rozsijanoğo svitla skladajetjsja z žovtuvatym prjamym sonjačnym svitlom i zağaljne osvitlennja ob'jektiv na Zemli staje bilym."
+        ],
+        [
+            "дуб!дуб\"дуб#дуб$дуб%дуб&дуб'дуб(дуб)дуб*дуб+дуб,дуб-дуб.дуб/дуб:дуб;дуб<дуб=дуб>дуб?дуб@дуб[дуб\\дуб]дуб^дуб_дуб`дуб{дуб|дуб}дуб~дуб",
+            "dub!dub\"dub#dub$dub%dub&dub'dub(dub)dub*dub+dub,dub-dub.dub/dub:dub;dub<dub=dub>dub?dub@dub[dub\\dub]dub^dub_dub`dub{dub|dub}dub~dub"
+        ],
+        [
+            "бод бод\tбод\nбод\rбод",
+            "bod bod\tbod\nbod\rbod"
+        ],
+        [
+            "об😎нап😘неп😭нєп🧐нїп😍нюп😀няп",
+            "ob😎nap😘nep😭njep🧐nïp😍njup😀njap"
+        ],
+        ]
+
+        data_c2l = [
+        [
+            "в’я в'я",
+            "v'ja v'ja"
+        ],
+        [
+            "Ї ї Й й Ё ё Ў ў",
+            "Ï ï J j Ö ö Ŭ ŭ"
+        ],
+        ]
+
+        data_l2c = [
+        [
+            "я є ю",
+            "jA jE jU"
+        ],
+        [
+            "Ї ї Ь ь Ч ч Г г Щ щ Ш ш Ж ж",
+            "Ï ï Ĵ ĵ Č č Ğ ğ Ŝ ŝ Š š Ž ž"
+        ],
+        [
+            "Ё ё Ў ў Ъ ъ Ы ы Э э",
+            "Ö ö Ŭ ŭ Ǒ ǒ Ȳ ȳ Ē ē"
+        ],
+        [
+            "А́ а́ Е́ е́ Є́ Є́ є́ є́ И́ и́ І́ і́ Ї́ ї́ О́ о́ У́ у́ Ю́ Ю́ ю́ ю́ Я́ Я́ я́ я́",
+            "Á á É é JÉ Jé jÉ jé Ý ý Í í Ḯ ḯ Ó ó Ú ú JÚ Jú jÚ jú JÁ Já jÁ já"
+        ],
+        [
+            "Є́с сЄ́с є́с сє́с Ї́с сЇ́с ї́с сї́с Ю́с сЮ́с ю́с сю́с Я́с сЯ́с я́с ся́с",
+            "Jés sJés jés sjés Ḯs sḮs ḯs sḯs Jús sJús jús sjús Jás sJás jás sjás"
+        ],
+        ]
+        data_c2lr.each do |cyr,lat|
+            q = @tr.encode(cyr, 'DSTU_9112_A')
+            assert_equal(lat, q, cyr)
+            t = @tr.decode(lat, 'DSTU_9112_A')
+            assert_equal(cyr, t, lat);
+        end
+        puts "DSTU_9112_A: c2lr #{data_c2lr.length} tests passed"
+        data_c2l.each do |cyr,lat|
+            q = @tr.encode(cyr, 'DSTU_9112_A')
+            assert_equal(lat, q, cyr)
+        end
+        puts "DSTU_9112_A: c2l #{data_c2l.length} tests passed"
+        data_l2c.each do |cyr,lat|
+            q = @tr.decode(lat, 'DSTU_9112_A')
+            assert_equal(cyr, q, lat);
+        end
+        puts "DSTU_9112_A: l2c #{data_l2c.length} tests passed"
+    end
+
+    def test_DSTU_9112_B()
+
+        data_c2lr = [
+        [
+            "Україна, Хмельницький",
+            "Ukrajina, Khmeljnycjkyj"
+        ],
+        [
+            "Щастям б’єш жук їх глицю в фон й ґедзь пріч.",
+            "Shchastjam b'jesh zhuk jikh ghlycju v fon j gedzj prich."
+        ],
+        [
+            "ь Ь ль льє льї лью лья лье льі льу льа льйо льо",
+            "hj Hj lj ljje ljji ljju ljja lj'e lj'i lj'u lj'a ljjo ljo"
+        ],
+        [
+            "Єл Їл Юл Ял",
+            "Jel Jil Jul Jal"
+        ],
+        [
+            "бь вь гь ґь дь жь зь кь ль мь нь пь рь сь ть фь хь ць чь шь щь",
+            "bj vj ghj gj dj zhj zj kj lj mj nj pj rj sj tj fj khj cj chj shj shchj"
+        ],
+        [
+            "бя вя гя ґя дя жя зя кя ля мя ня пя ря ся тя фя хя ця чя шя щя",
+            "bja vja ghja gja dja zhja zja kja lja mja nja pja rja sja tja fja khja cja chja shja shchja"
+        ],
+        [
+            "б’я в’я г’я ґ’я д’я ж’я з’я к’я л’я м’я н’я п’я р’я с’я т’я ф’я х’я ц’я ч’я ш’я щ’я",
+            "b'ja v'ja gh'ja g'ja d'ja zh'ja z'ja k'ja l'ja m'ja n'ja p'ja r'ja s'ja t'ja f'ja kh'ja c'ja ch'ja sh'ja shch'ja"
+        ],
+        [
+            "бй бйо вй гй ґй дй жй зй кй лй мй нй пй рй сй тй фй хй цй чй шй щй",
+            "b'j b'jo v'j gh'j g'j d'j zh'j z'j k'j l'j m'j n'j p'j r'j s'j t'j f'j kh'j c'j ch'j sh'j shch'j"
+        ],
+        [
+            "ня ньа н’я нь'н ньн",
+            "nja nj'a n'ja nj'n njn"
+        ],
+        [
+            "рос дыня эзёдынъ. бр кроў.",
+            "ros dywnja ehwzjowdywnoh. br krouh."
+        ],
+        [
+            "А́ а́ Е́ е́ Є́ є́ И́ и́ І́ і́ Ї́ ї́ О́ о́ У́ у́ Ю́ ю́ Я́ я́",
+            "Á á É é JÉ jé Ý ý Í í JÍ jí Ó ó Ú ú JÚ jú JÁ já"
+        ],
+        [
+            "Є́с сЄ́с є́с сє́с Ї́с сЇ́с ї́с сї́с Ю́с сЮ́с ю́с сю́с Я́с сЯ́с я́с ся́с",
+            "Jés sJés jés sjés Jís sJís jís sjís Jús sJús jús sjús Jás sJás jás sjás"
+        ],
+        [
+            "' ім’я 'жук' \"жук\" ' '",
+            "' im'ja 'zhuk' \"zhuk\" ' '"
+        ],
+        [
+            "Сонце світить майже білим світлом, однак через сильніше розсіювання і поглинання короткохвильової частини спектра атмосферою Землі пряме світло Сонця біля поверхні нашої планети набуває певного жовтого відтінку. Якщо небо ясне, то блакитний відтінок розсіяного світла складається з жовтуватим прямим сонячним світлом і загальне освітлення об’єктів на Землі стає білим.",
+            "Sonce svitytj majzhe bilym svitlom, odnak cherez syljnishe rozsijuvannja i poghlynannja korotkokhvyljovoji chastyny spektra atmosferoju Zemli prjame svitlo Soncja bilja poverkhni nashoji planety nabuvaje pevnogho zhovtogho vidtinku. Jakshcho nebo jasne, to blakytnyj vidtinok rozsijanogho svitla skladajetjsja z zhovtuvatym prjamym sonjachnym svitlom i zaghaljne osvitlennja ob'jektiv na Zemli staje bilym."
+        ],
+        [
+            "дуб!дуб\"дуб#дуб$дуб%дуб&дуб'дуб(дуб)дуб*дуб+дуб,дуб-дуб.дуб/дуб:дуб;дуб<дуб=дуб>дуб?дуб@дуб[дуб\\дуб]дуб^дуб_дуб`дуб{дуб|дуб}дуб~дуб",
+            "dub!dub\"dub#dub$dub%dub&dub'dub(dub)dub*dub+dub,dub-dub.dub/dub:dub;dub<dub=dub>dub?dub@dub[dub\\dub]dub^dub_dub`dub{dub|dub}dub~dub"
+        ],
+        [
+            "бод бод\tбод\nбод\rбод",
+            "bod bod\tbod\nbod\rbod"
+        ],
+        [
+            "об😎нап😘неп😭нєп🧐нїп😍нюп😀няп",
+            "ob😎nap😘nep😭njep🧐njip😍njup😀njap"
+        ],
+        ]
+
+        data_c2l = [
+        [
+            "в’я в'я",
+            "v'ja v'ja"
+        ],
+        [
+            "Ї ї Й й Ё ё Ў ў",
+            "JI ji J j JOW jow UH uh"
+        ],
+        ]
+
+        data_l2c = [
+        [
+            "я ї є ю г ж х щ ш ч ь",
+            "jA jI jE jU gH zH kH sHcH sH cH hJ"
+        ],
+        [
+            "А́ а́ Е́ е́ Є́ Є́ є́ є́ И́ и́ І́ і́ Ї́ Ї́ ї́ ї́ О́ о́ У́ у́ Ю́ Ю́ ю́ ю́ Я́ Я́ я́ я́",
+            "Á á É é JÉ Jé jÉ jé Ý ý Í í JÍ Jí jÍ jí Ó ó Ú ú JÚ Jú jÚ jú JÁ Já jÁ já"
+        ],
+        [
+            "Є́с сЄ́с є́с сє́с Ї́с сЇ́с ї́с сї́с Ю́с сЮ́с ю́с сю́с Я́с сЯ́с я́с ся́с",
+            "Jés sJés jés sjés Jís sJís jís sjís Jús sJús jús sjús Jás sJás jás sjás"
+        ],
+        ]
+        data_c2lr.each do |cyr,lat|
+            q = @tr.encode(cyr, 'DSTU_9112_B')
+            assert_equal(lat, q, cyr)
+            t = @tr.decode(lat, 'DSTU_9112_B')
+            assert_equal(cyr, t, lat);
+        end
+        puts "DSTU_9112_B: c2lr #{data_c2lr.length} tests passed"
+        data_c2l.each do |cyr,lat|
+            q = @tr.encode(cyr, 'DSTU_9112_B')
+            assert_equal(lat, q, cyr)
+        end
+        puts "DSTU_9112_B: c2l #{data_c2l.length} tests passed"
+        data_l2c.each do |cyr,lat|
+            q = @tr.decode(lat, 'DSTU_9112_B')
+            assert_equal(cyr, q, lat);
+        end
+        puts "DSTU_9112_B: l2c #{data_l2c.length} tests passed"
+    end
+
+    def test_KMU_55()
+
+        data_c2l = [
+        [
+            "Україна, Хмельницький",
+            "Ukraina, Khmelnytskyi"
+        ],
+        [
+            "Щастям б’єш жук їх глицю в фон й ґедзь пріч.",
+            "Shchastiam biesh zhuk yikh hlytsiu v fon y gedz prich."
+        ],
+        [
+            "згин зГ зГин Згин Зг ЗГ ЗГИН",
+            "zghyn zGH zGhyn Zghyn Zgh ZGH ZGHYN"
+        ],
+        [
+            "ь Ь ль льє льї лью лья лье льі льу льа льйо льо",
+            "  l lie li liu lia le li lu la lio lo"
+        ],
+        [
+            "Єл Їл Юл Ял",
+            "Yel Yil Yul Yal"
+        ],
+        [
+            "бь вь гь ґь дь жь зь кь ль мь нь пь рь сь ть фь хь ць чь шь щь",
+            "b v h g d zh z k l m n p r s t f kh ts ch sh shch"
+        ],
+        [
+            "бя вя гя ґя дя жя зя кя ля мя ня пя ря ся тя фя хя ця чя шя щя",
+            "bia via hia gia dia zhia zia kia lia mia nia pia ria sia tia fia khia tsia chia shia shchia"
+        ],
+        [
+            "б’я в’я г’я ґ’я д’я ж’я з’я к’я л’я м’я н’я п’я р’я с’я т’я ф’я х’я ц’я ч’я ш’я щ’я",
+            "bia via hia gia dia zhia zia kia lia mia nia pia ria sia tia fia khia tsia chia shia shchia"
+        ],
+        [
+            "бй бйо вй гй ґй дй жй зй кй лй мй нй пй рй сй тй фй хй цй чй шй щй",
+            "bi bio vi hi gi di zhi zi ki li mi ni pi ri si ti fi khi tsi chi shi shchi"
+        ],
+        [
+            "А́ а́ Е́ е́ Є́ є́ И́ и́ І́ і́ Ї́ ї́ О́ о́ У́ у́ Ю́ ю́ Я́ я́",
+            "Á á É é YÉ yé Ý ý Í í YÍ yí Ó ó Ú ú YÚ yú YÁ yá"
+        ],
+        [
+            "Є́с сЄ́с є́с сє́с Ї́с сЇ́с ї́с сї́с Ю́с сЮ́с ю́с сю́с Я́с сЯ́с я́с ся́с",
+            "Yés sIés yés siés Yís sÍs yís sís Yús sIús yús siús Yás sIás yás siás"
+        ],
+        [
+            "' ім’я 'жук' \"жук\" ' '",
+            "' imia 'zhuk' \"zhuk\" ' '"
+        ],
+        [
+            "Сонце світить майже білим світлом, однак через сильніше розсіювання і поглинання короткохвильової частини спектра атмосферою Землі пряме світло Сонця біля поверхні нашої планети набуває певного жовтого відтінку. Якщо небо ясне, то блакитний відтінок розсіяного світла складається з жовтуватим прямим сонячним світлом і загальне освітлення об’єктів на Землі стає білим.",
+            "Sontse svityt maizhe bilym svitlom, odnak cherez sylnishe rozsiiuvannia i pohlynannia korotkokhvylovoi chastyny spektra atmosferoiu Zemli priame svitlo Sontsia bilia poverkhni nashoi planety nabuvaie pevnoho zhovtoho vidtinku. Yakshcho nebo yasne, to blakytnyi vidtinok rozsiianoho svitla skladaietsia z zhovtuvatym priamym soniachnym svitlom i zahalne osvitlennia obiektiv na Zemli staie bilym."
+        ],
+        [
+            "в’я в'я",
+            "via via"
+        ],
+        [
+            "дуб!дуб\"дуб#дуб$дуб%дуб&дуб'дуб(дуб)дуб*дуб+дуб,дуб-дуб.дуб/дуб:дуб;дуб<дуб=дуб>дуб?дуб@дуб[дуб\\дуб]дуб^дуб_дуб`дуб{дуб|дуб}дуб~дуб",
+            "dub!dub\"dub#dub$dub%dub&dubdub(dub)dub*dub+dub,dub-dub.dub/dub:dub;dub<dub=dub>dub?dub@dub[dub\\dub]dub^dub_dub`dub{dub|dub}dub~dub"
+        ],
+        [
+            "бод бод\tбод\nбод\rбод",
+            "bod bod\tbod\nbod\rbod"
+        ],
+        [
+            "об😎нап😘неп😭нєп🧐нїп😍нюп😀няп",
+            "ob😎nap😘nep😭niep🧐nip😍niup😀niap"
+        ],
+        ]
+        data_c2l.each do |cyr,lat|
+            q = @tr.encode(cyr, 'KMU_55')
+            assert_equal(lat, q, cyr)
+        end
+        puts "KMU_55: c2l #{data_c2l.length} tests passed"
+    end
+
+end
+
+test = TestUkrainianLatin.new
+spec = TestUkrainianLatin.instance_methods(false).grep(/^test_/)
+spec.each do |name|
+    test.send(name)
+end
diff --git a/ruby/uklatn.gemspec b/ruby/uklatn.gemspec
new file mode 100644
index 0000000..6a33d42
--- /dev/null
+++ b/ruby/uklatn.gemspec
@@ -0,0 +1,16 @@
+Gem::Specification.new do |s|
+    s.name = 'uklatn'
+    s.version = '1.13.0'
+    s.license = 'MIT'
+    s.summary = 'Ukrainian Cyrillic transliteration to Latin script'
+    s.description = <<~EOS
+    Ukraine national transliteration schemes:
+    - DSTU 9112:2021,
+    - KMU 55:2010 (not reversible)
+    EOS
+    s.author = 'Pavlo Ivashkov'
+    s.homepage = 'https://github.com/paiv/uklatn'
+    s.metadata = { 'source_code_uri' => 'https://github.com/paiv/uklatn' }
+    s.required_ruby_version = '>= 2.6.0'
+    s.files = ['lib/uklatn.rb']
+end
diff --git a/tools/Makefile b/tools/Makefile
index 6b7e992..e3925ff 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -3,6 +3,7 @@
 .PHONY: java
 .PHONY: js
 .PHONY: py
+.PHONY: ruby
 .PHONY: swift
 
 PYTHON ?= python
@@ -34,6 +35,12 @@ py:
 	@echo "# Generated by gentests.py, do not edit.\n" > "$(PROJECT_ROOT)/python/tests/uklatn_tests.py"
 	@$(PYTHON) gentests.py py >> "$(PROJECT_ROOT)/python/tests/uklatn_tests.py"
 
+ruby:
+	@echo "# Generated by gentables.py, do not edit.\n" > "$(PROJECT_ROOT)/ruby/lib/uklatn.rb"
+	@$(PYTHON) gentables.py ruby >> "$(PROJECT_ROOT)/ruby/lib/uklatn.rb"
+	@echo "# Generated by gentests.py, do not edit.\n" > "$(PROJECT_ROOT)/ruby/test/uklatn/test_uklatn.rb"
+	@$(PYTHON) gentests.py ruby >> "$(PROJECT_ROOT)/ruby/test/uklatn/test_uklatn.rb"
+
 swift:
 	@echo "/* Generated by gentables.py, do not edit. */\n" > "$(PROJECT_ROOT)/swift/Sources/UkrainianLatin/UKLatn.swift"
 	@$(PYTHON) gentables.py swift >> "$(PROJECT_ROOT)/swift/Sources/UkrainianLatin/UKLatn.swift"
diff --git a/tools/gen/gen_ruby.py b/tools/gen/gen_ruby.py
new file mode 100755
index 0000000..dc8438e
--- /dev/null
+++ b/tools/gen/gen_ruby.py
@@ -0,0 +1,230 @@
+import io
+import json
+import logging
+import re
+import textwrap
+from pathlib import Path
+
+
+logger = logging.getLogger(Path(__file__).stem)
+
+
+def gen_tests(fns):
+    def _parse_tests(fn):
+        def parse_kind(s):
+            match s.lower().split():
+                case ['cyr', '<>', 'lat']: return 'c2lr'
+                case ['lat', '<>', 'cyr']: return 'l2cr'
+                case ['cyr', '>', 'lat']: return 'c2l'
+                case ['lat', '>', 'cyr']: return 'l2c'
+                case _:
+                    raise Exception(f'unknown test kind: {s!r}')
+        with fn.open() as fp:
+            data = json.load(fp)
+        return [[parse_kind(obj['test']), obj['cyr'], obj['lat']] for obj in data]
+
+    def table_name(s):
+        return re.sub(r'test_', '', s)
+    def _j(s):
+        return json.dumps(s, ensure_ascii=False)
+
+    def _emit_testdata(kind, data, table, file):
+        data = [(cyr,lat) for k,cyr,lat in data if k == kind]
+        if not data: return
+        dump = ''.join(f'\n[\n    {_j(cyr)},\n    {_j(lat)}\n],' for cyr,lat in data)
+        so = f'\ndata_{kind} = [{dump}\n]'
+        so = textwrap.indent(so, ' ' * 8)
+        print(so, file=file)
+
+    def _emit_tests(kind, data, table, file):
+        data = [(cyr,lat) for k,cyr,lat in data if k == kind]
+        if not data: return
+        print(f'        data_{kind}.each do |cyr,lat|', file=file)
+        if kind[0] == 'c':
+            print(f'            q = @tr.encode(cyr, {table!r})', file=file)
+            print(f'            assert_equal(lat, q, cyr)', file=file)
+        else:
+            print(f'            q = @tr.decode(lat, {table!r})', file=file)
+            print(f'            assert_equal(cyr, q, lat);', file=file)
+        if kind[-1] == 'r':
+            if kind[0] == 'c':
+                print(f'            t = @tr.decode(lat, {table!r})', file=file)
+                print(f'            assert_equal(cyr, t, lat);', file=file)
+            else:
+                print(f'            t = @tr.encode(cyr, {table!r})', file=file)
+                print(f'            assert_equal(lat, t, cyr)', file=file)
+        print('        end', file=file)
+        print(f'        puts "{table}: {kind} #{{data_{kind}.length}} tests passed"', file=file)
+
+    def _emit_testset(data, table, file):
+        print(f'\n    def test_{table}()', file=file)
+        _emit_testdata('c2lr', data, table, file=file)
+        _emit_testdata('l2cr', data, table, file=file)
+        _emit_testdata('c2l', data, table, file=file)
+        _emit_testdata('l2c', data, table, file=file)
+        _emit_tests('c2lr', data, table, file=file)
+        _emit_tests('l2cr', data, table, file=file)
+        _emit_tests('c2l', data, table, file=file)
+        _emit_tests('l2c', data, table, file=file)
+        print('    end', file=file)
+
+    context = dict()
+    with io.StringIO() as so:
+        for fn in fns:
+            logger.info(f'processing {fn!s}')
+            name = fn.stem
+            table = table_name(name)
+            data = _parse_tests(fn)
+            _emit_testset(data, table, file=so)
+        context['test_cases'] = so.getvalue()
+
+    context['test_raise'] =  '"failed\\n input: #{input}\\nexpect: #{expect}\\nactual: #{actual}\\n        #{arr}"'
+
+    template = '''require_relative '../../lib/uklatn.rb'
+
+class TestUkrainianLatin
+
+    def initialize
+        @tr = UkrainianLatin.new
+    end
+
+    def assert_equal(expect, actual, input)
+        if expect != actual
+            s = actual.chars
+            arr = expect.chars.map {{|c| c == s.shift ? ' ' : '^'}}.join
+            raise {test_raise}
+        end
+    end
+{test_cases}
+end
+
+test = TestUkrainianLatin.new
+spec = TestUkrainianLatin.instance_methods(false).grep(/^test_/)
+spec.each do |name|
+    test.send(name)
+end
+'''
+    text = template.format(**context)
+    return text
+
+
+def gen_transforms(fns, default_table=None):
+    def table_name(s):
+        s, = re.findall(r'uk_Latn_(.*?)(?:-uk)?\s*$', s, flags=re.I)
+        return s.replace('-', '_')
+    def class_name(s):
+        return 'Uklatn_' + s.replace('-', '_')
+    def _isdec(s):
+        return s.startswith('uk_Latn_')
+    def _j(s):
+        return json.dumps(s, ensure_ascii=False)
+    def _load_rules(data):
+        return [s if isinstance(s, str) else [
+            '|'.join(r['regex'] for r in s),
+            [r['map'] for r in s]
+        ] for s in data]
+
+    def _emit_trrules(rules, file):
+        so = ''
+        for sid, section in enumerate(rules):
+            if not isinstance(section, str):
+                rx, maps = section
+                gn = len(maps)
+                so += f'@rx{sid} = /{rx}/\n'
+                so += f'@maps{sid} = [\n'
+                for d in maps:
+                    m = ','.join((_j(k) + '=>' + _j(v)) for k,v in d.items())
+                    so += f'    {{{m}}},\n'
+                so += ']\n'
+        print(textwrap.indent(so, ' ' * 8), end='', file=file)
+
+    def _emit_trbody(rules, file):
+        so = ''
+        for sid, section in enumerate(rules):
+            if isinstance(section, str):
+                if section not in ('NFC', 'NFD', 'NFKC', 'NFKD'):
+                    raise Exception(f'invalid transform: {section!r}')
+                so += f'text = text.unicode_normalize(:{section.lower()})\n'
+            else:
+                rx, maps = section
+                gn = len(maps)
+                so += f'text = text.gsub(@rx{sid}) do |m|\n'
+                for mid in reversed(range(1, gn+1)):
+                    so += f'    next @maps{sid}[{mid-1}].fetch(${mid}, ${mid}) unless ${mid}.nil?\n'
+                so += '    m\n'
+                so += 'end\n'
+        print(textwrap.indent(so, ' ' * 8), end='', file=file)
+
+    def _emit_tr(cname, rules, file):
+        rules = _load_rules(rules)
+        print(f'class {cname} # :nodoc:', file=file)
+        print('    def initialize()', file=file)
+        _emit_trrules(rules, file=file)
+        print('    end\n', file=file)
+        print('    def transform(text)', file=file)
+        _emit_trbody(rules, file=file)
+        print('    end', file=file)
+        print('end\n', file=file)
+
+    context = dict()
+    tables = dict()
+    with io.StringIO() as so:
+        for fn in fns:
+            logger.info(f'processing {fn!s}')
+            with fn.open() as fp:
+                rules = json.load(fp)
+            name = fn.stem
+            table = table_name(name)
+            cname = class_name(name)
+            if table not in tables:
+                tables[table] = [None, None]
+            tables[table][_isdec(name)] = cname
+            _emit_tr(cname, rules, so)
+        classdefs_tables = textwrap.indent(so.getvalue(), ' ' * 4)
+
+    def _emit_tabledef(tables):
+        so = ''
+        so += 'TABLES = Hash.new([nil, nil]) # :nodoc:'
+        for tid, (table, (enc, dec)) in enumerate(tables.items(), 1):
+            dasht = table.replace('_', '-')
+            enc = f'{enc}.new()' if enc else 'nil'
+            dec = f'{dec}.new()' if dec else 'nil'
+            so += f'\nTABLES[{table!r}] = [{enc}, {dec}]'
+            so += f'\nTABLES[{dasht!r}] = TABLES[{table!r}]'
+        so = textwrap.indent(so, ' ' * 4)
+        return so
+
+    tabledef = _emit_tabledef(tables)
+
+    context['global_tables'] = classdefs_tables + tabledef
+    context['default_table'] = default_table
+
+    template = '''\
+# Ukrainian Cyrillic transliteration to and from Latin script.
+#
+# Tables:
+# 'DSTU_9112_A': DSTU 9112:2021 System A
+# 'DSTU_9112_B': DSTU 9112:2021 System B
+# 'KMU_55': KMU 55:2010, not reversible
+class UkrainianLatin
+
+    # Transliterates a string of Ukrainian Cyrillic to Latin script.
+    def encode(text, table = {default_table!r})
+        tr = TABLES[table][0]
+        return tr.transform(text) if tr
+        raise ArgumentError.new("invalid table #{{table}}")
+    end
+
+    # Re-transliterates a string of Ukrainian Latin to Cyrillic script.
+    def decode(text, table = {default_table!r})
+        tr = TABLES[table][1]
+        return tr.transform(text) if tr
+        raise ArgumentError.new("invalid table #{{table}}")
+    end
+
+{global_tables}
+end
+'''
+    text = template.format(**context)
+    return text
+
diff --git a/tools/gentables.py b/tools/gentables.py
index b42d628..c9c4bd5 100755
--- a/tools/gentables.py
+++ b/tools/gentables.py
@@ -73,6 +73,17 @@ def gen_py(src):
     logger.info('PY generator end')
 
 
+def gen_ruby(src):
+    logger.info('Ruby generator start')
+    from gen import gen_ruby
+
+    source = _basegen(args, 'src/regex', 'uk*.json', gen_ruby.gen_transforms)
+    for text in source:
+        print(text, end='')
+
+    logger.info('Ruby generator end')
+
+
 def gen_swift(src):
     logger.info('Swift generator start')
     from gen import gen_swift
@@ -102,6 +113,10 @@ def gen_swift(src):
     parse_py.add_argument('source', nargs='*', help='source directory')
     parse_py.set_defaults(func=gen_py)
 
+    parse_ruby = subpar.add_parser('ruby', help='Ruby code generator')
+    parse_ruby.add_argument('source', nargs='*', help='source directory')
+    parse_ruby.set_defaults(func=gen_ruby)
+
     parse_java = subpar.add_parser('java', help='Java code generator')
     parse_java.add_argument('source', nargs='*', help='source directory')
     parse_java.set_defaults(func=gen_java)
diff --git a/tools/gentests.py b/tools/gentests.py
index aecd008..fc5413e 100755
--- a/tools/gentests.py
+++ b/tools/gentests.py
@@ -70,6 +70,17 @@ def gen_py(args):
     logger.info('PY generator end')
 
 
+def gen_ruby(args):
+    logger.info('Ruby generator start')
+    from gen import gen_ruby
+
+    source = _basegen(args, 'src/tests', 'test*.json', gen_ruby.gen_tests)
+    for text in source:
+        print(text, end='')
+
+    logger.info('Ruby generator end')
+
+
 def gen_swift(args):
     logger.info('Swift generator start')
     from gen import gen_swift
@@ -103,6 +114,10 @@ def gen_swift(args):
     parse_java.add_argument('source', nargs='*', help='source directory')
     parse_java.set_defaults(func=gen_java)
 
+    parse_ruby = subpar.add_parser('ruby', help='Ruby code generator')
+    parse_ruby.add_argument('source', nargs='*', help='source directory')
+    parse_ruby.set_defaults(func=gen_ruby)
+
     parse_swift = subpar.add_parser('swift', help='Swfit code generator')
     parse_swift.add_argument('source', nargs='*', help='source directory')
     parse_swift.set_defaults(func=gen_swift)