diff --git a/.gitignore b/.gitignore
index 922dc59..e18f315 100644
--- a/.gitignore
+++ b/.gitignore
@@ -84,6 +84,7 @@ cmake-build-*/
 
 # IntelliJ
 out/
+*.iml
 
 # mpeltonen/sbt-idea plugin
 .idea_modules/
diff --git a/haskell/.gitignore b/haskell/.gitignore
new file mode 100644
index 0000000..d09889e
--- /dev/null
+++ b/haskell/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+haskell.cabal
+*~
\ No newline at end of file
diff --git a/haskell/ChangeLog.md b/haskell/ChangeLog.md
new file mode 100644
index 0000000..69e85a4
--- /dev/null
+++ b/haskell/ChangeLog.md
@@ -0,0 +1,3 @@
+# Changelog for haskell
+
+## Unreleased changes
diff --git a/haskell/LICENSE b/haskell/LICENSE
new file mode 100644
index 0000000..e793919
--- /dev/null
+++ b/haskell/LICENSE
@@ -0,0 +1,30 @@
+Copyright Julien Debon (c) 2019
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Julien Debon nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/haskell/README.md b/haskell/README.md
new file mode 100644
index 0000000..b237d8a
--- /dev/null
+++ b/haskell/README.md
@@ -0,0 +1 @@
+# haskell
diff --git a/haskell/Setup.hs b/haskell/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/haskell/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/haskell/app/Main.hs b/haskell/app/Main.hs
new file mode 100644
index 0000000..de1c1ab
--- /dev/null
+++ b/haskell/app/Main.hs
@@ -0,0 +1,6 @@
+module Main where
+
+import Lib
+
+main :: IO ()
+main = someFunc
diff --git a/haskell/package.yaml b/haskell/package.yaml
new file mode 100644
index 0000000..f02f6e1
--- /dev/null
+++ b/haskell/package.yaml
@@ -0,0 +1,81 @@
+name:                haskell
+version:             0.1.0.0
+github:              "Sir4ur0n/haskell"
+license:             BSD3
+author:              "Julien Debon"
+maintainer:          "debon.julien@gmail.com"
+copyright:           "WTFPL"
+
+extra-source-files:
+  - README.md
+  - ChangeLog.md
+
+description:         Please see the README on GitHub at <https://github.com/Sir4ur0n/haskell#readme>
+
+ghc-options:
+  - -Wall
+  - -Wcompat
+  # Some additional compiler warnings from https://medium.com/mercury-bank/enable-all-the-warnings-a0517bc081c3
+  - -Wincomplete-uni-patterns
+  - -Wincomplete-record-updates
+  - -Wmissing-home-modules
+  - -Widentities
+  - -Wredundant-constraints
+  # Don't optimize by default (faster build time)
+  - -O0
+
+dependencies:
+  - base >= 4.7 && < 5
+  - hlint
+  - scientific
+  - time
+  - text
+
+library:
+  source-dirs: src
+
+executables:
+  haskell-exe:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+      - -threaded
+      - -rtsopts
+      - -with-rtsopts=-N
+    dependencies:
+      - haskell
+
+tests:
+  haskell-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+      - -Wall
+      - -Wcompat
+      - -Wmissing-home-modules
+      - -Widentities
+      - -Wredundant-constraints
+      # Our test convention for HUnit would make it unnecessarily verbose to add the signature of each test
+      - -fno-warn-missing-signatures
+      # Delegate to Tasty to discover tests
+      - -fno-warn-missing-export-lists
+      # Use orphan instances in tests to add Arbitrary (QuickCheck) behaviour without impacting the Production type
+      - -fno-warn-orphans
+      - -threaded
+      - -rtsopts
+      - -with-rtsopts=-N
+      - -Wno-unused-imports
+      - -O0
+    dependencies:
+      - haskell
+      # Property based testing
+      - QuickCheck
+      - quickcheck-instances
+      - quickcheck-arbitrary-adt
+      # Unit testing
+      - HUnit
+      # Test aggregation and discovery
+      - tasty
+      - tasty-quickcheck
+      - tasty-hunit
+      - tasty-discover
\ No newline at end of file
diff --git a/haskell/src/Invariant.hs b/haskell/src/Invariant.hs
new file mode 100644
index 0000000..eb29997
--- /dev/null
+++ b/haskell/src/Invariant.hs
@@ -0,0 +1,6 @@
+module Invariant (LocalDate, isNewYearEve) where
+
+type LocalDate = (Integer, Int, Int)
+
+isNewYearEve :: LocalDate -> Bool
+isNewYearEve (_, month, day) = month == 12 && day == 31
\ No newline at end of file
diff --git a/haskell/src/Lib.hs b/haskell/src/Lib.hs
new file mode 100644
index 0000000..2cd4f41
--- /dev/null
+++ b/haskell/src/Lib.hs
@@ -0,0 +1,6 @@
+module Lib
+    ( someFunc
+    ) where
+
+someFunc :: IO ()
+someFunc = putStrLn "someFunc"
\ No newline at end of file
diff --git a/haskell/stack.yaml b/haskell/stack.yaml
new file mode 100644
index 0000000..fff9875
--- /dev/null
+++ b/haskell/stack.yaml
@@ -0,0 +1,64 @@
+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-13.6
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+# - location:
+#    git: https://github.com/commercialhaskell/stack.git
+#    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#  subdirs:
+#  - auto-update
+#  - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# using the same syntax as the packages field.
+# (e.g., acme-missiles-0.3)
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=1.9"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor
diff --git a/haskell/test/InvariantSpec.hs b/haskell/test/InvariantSpec.hs
new file mode 100644
index 0000000..ae7c738
--- /dev/null
+++ b/haskell/test/InvariantSpec.hs
@@ -0,0 +1,17 @@
+module InvariantSpec where
+
+import           Invariant
+import           Test.QuickCheck
+import           Test.QuickCheck.Arbitrary.ADT
+import           Test.QuickCheck.Instances.Scientific
+import           Test.QuickCheck.Instances.Time
+import           Test.Tasty.HUnit
+import           Test.Tasty.QuickCheck
+
+test_2018_12_31 = testCase "2018-12-31 is a new year's eve" $ isNewYearEve (2018, 12, 31) @?= True
+
+test_1989_12_31 = testCase "1989-12-31 is a new year's eve" $ isNewYearEve (1989, 12, 31) @?= True
+
+test_2018_12_25 = testCase "2018-12-25 is not a new year's eve" $ isNewYearEve (2018, 12, 25) @?= False
+
+test_2018_08_25 = testCase "2018-08-31 is not a new year's eve" $ isNewYearEve (2018, 8, 31) @?= False
\ No newline at end of file
diff --git a/haskell/test/Spec.hs b/haskell/test/Spec.hs
new file mode 100644
index 0000000..e492019
--- /dev/null
+++ b/haskell/test/Spec.hs
@@ -0,0 +1,2 @@
+{-# OPTIONS_GHC -F -pgmF tasty-discover -fno-warn-missing-import-lists #-}
+-- Driver module responsible for discovering all other modules, and tests inside modules, using tasty-discover preprocessor.
diff --git a/build.gradle.kts b/java/build.gradle.kts
similarity index 100%
rename from build.gradle.kts
rename to java/build.gradle.kts
diff --git a/gradle/wrapper/gradle-wrapper.jar b/java/gradle/wrapper/gradle-wrapper.jar
similarity index 100%
rename from gradle/wrapper/gradle-wrapper.jar
rename to java/gradle/wrapper/gradle-wrapper.jar
diff --git a/gradle/wrapper/gradle-wrapper.properties b/java/gradle/wrapper/gradle-wrapper.properties
similarity index 100%
rename from gradle/wrapper/gradle-wrapper.properties
rename to java/gradle/wrapper/gradle-wrapper.properties
diff --git a/gradlew b/java/gradlew
old mode 100755
new mode 100644
similarity index 100%
rename from gradlew
rename to java/gradlew
diff --git a/gradlew.bat b/java/gradlew.bat
similarity index 100%
rename from gradlew.bat
rename to java/gradlew.bat
diff --git a/settings.gradle b/java/settings.gradle
similarity index 100%
rename from settings.gradle
rename to java/settings.gradle
diff --git a/src/main/java/Analogous.java b/java/src/main/java/Analogous.java
similarity index 100%
rename from src/main/java/Analogous.java
rename to java/src/main/java/Analogous.java
diff --git a/src/main/java/Idempotence.java b/java/src/main/java/Idempotence.java
similarity index 100%
rename from src/main/java/Idempotence.java
rename to java/src/main/java/Idempotence.java
diff --git a/src/main/java/Invariant.java b/java/src/main/java/Invariant.java
similarity index 100%
rename from src/main/java/Invariant.java
rename to java/src/main/java/Invariant.java
diff --git a/src/main/java/Inverse.java b/java/src/main/java/Inverse.java
similarity index 100%
rename from src/main/java/Inverse.java
rename to java/src/main/java/Inverse.java
diff --git a/src/main/java/analogous/Sport.java b/java/src/main/java/analogous/Sport.java
similarity index 100%
rename from src/main/java/analogous/Sport.java
rename to java/src/main/java/analogous/Sport.java
diff --git a/src/main/java/analogous/User.java b/java/src/main/java/analogous/User.java
similarity index 100%
rename from src/main/java/analogous/User.java
rename to java/src/main/java/analogous/User.java
diff --git a/src/main/java/inverse/Price.java b/java/src/main/java/inverse/Price.java
similarity index 100%
rename from src/main/java/inverse/Price.java
rename to java/src/main/java/inverse/Price.java
diff --git a/src/main/java/inverse/PriceType.java b/java/src/main/java/inverse/PriceType.java
similarity index 100%
rename from src/main/java/inverse/PriceType.java
rename to java/src/main/java/inverse/PriceType.java
diff --git a/src/test/java/AnalogousTest.java b/java/src/test/java/AnalogousTest.java
similarity index 100%
rename from src/test/java/AnalogousTest.java
rename to java/src/test/java/AnalogousTest.java
diff --git a/src/test/java/IdempotenceTest.java b/java/src/test/java/IdempotenceTest.java
similarity index 100%
rename from src/test/java/IdempotenceTest.java
rename to java/src/test/java/IdempotenceTest.java
diff --git a/src/test/java/InvariantTest.java b/java/src/test/java/InvariantTest.java
similarity index 100%
rename from src/test/java/InvariantTest.java
rename to java/src/test/java/InvariantTest.java
diff --git a/src/test/java/InverseTest.java b/java/src/test/java/InverseTest.java
similarity index 100%
rename from src/test/java/InverseTest.java
rename to java/src/test/java/InverseTest.java
diff --git a/src/test/java/analogous/SportGen.java b/java/src/test/java/analogous/SportGen.java
similarity index 100%
rename from src/test/java/analogous/SportGen.java
rename to java/src/test/java/analogous/SportGen.java
diff --git a/src/test/java/analogous/UserGen.java b/java/src/test/java/analogous/UserGen.java
similarity index 100%
rename from src/test/java/analogous/UserGen.java
rename to java/src/test/java/analogous/UserGen.java
diff --git a/src/test/java/inverse/PriceGen.java b/java/src/test/java/inverse/PriceGen.java
similarity index 100%
rename from src/test/java/inverse/PriceGen.java
rename to java/src/test/java/inverse/PriceGen.java