diff --git a/CHANGELOG.md b/CHANGELOG.md
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--- /dev/null
+++ b/CHANGELOG.md
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+# Changelog for `derive-is-data-con`
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to the
+[Haskell Package Versioning Policy](https://pvp.haskell.org/).
+
+## 0.1.0.0 - 2025-02-19
+
+Initial Release
diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,26 @@
+Copyright 2025 Author name here
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1.  Redistributions of source code must retain the above copyright notice, this
+    list of conditions and the following disclaimer.
+
+2.  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.
+
+3.  Neither the name of the copyright holder nor the names of its 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 HOLDER 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/README.md b/README.md
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--- /dev/null
+++ b/README.md
@@ -0,0 +1,66 @@
+# derive-is-data-con
+
+This package will generate data constructor predicate functions
+
+```haskell
+    derive_is ''Bool
+  ======>
+    isFalse :: Bool -> Bool
+    isTrue :: Bool -> Bool
+    isFalse False = True
+    isFalse _ = False
+    isTrue True = True
+    isTrue _ = False
+```
+
+Above code will generate isTrue and isFalse functions. The function is 'is' + data constructor. 
+
+For operators, there is a function that translates to string
+
+```haskell
+charToString :: Char -> String
+charToString '~' = "Tilde"
+charToString '!' = "Bang"
+charToString '@' = "At"
+charToString '#' = "Hash"
+charToString '$' = "Dollar"
+charToString '%' = "Percent"
+charToString '^' = "Caret"
+charToString '&' = "And"
+charToString '*' = "Star"
+charToString '-' = "Minus"
+charToString '+' = "Plus"
+charToString '=' = "Equal"
+charToString '|' = "Pipe"
+charToString '\\' = "Backslash"
+charToString '/' = "Slash"
+charToString '<' = "Lt"
+charToString '>' = "Gt"
+charToString ':' = "Colon"
+charToString '?' = "Question"
+charToString '.' = "Dot"
+-- charToString '[' = "LSquareBracket" -- I do not want to support derive_is ''[]. One should use null function instead.
+-- charToString ']' = "RSquareBracket"
+```
+
+For example `(:=:)` will be translated into `isColonStarColon` function
+
+For gadt data type
+
+```haskell
+data Gadt a b where
+    (:*:), (:=:)  :: a -> b -> Gadt a b
+```
+
+The following code will be generated:
+
+```haskell
+    derive_is ''Gadt 
+  ======>
+    isColonStarColon :: Gadt a_a54E a_a54F -> Bool
+    isColonEqualColon :: Gadt a_a54G a_a54H -> Bool
+    isColonStarColon ((:*:) _ _) = True
+    isColonStarColon _ = False
+    isColonEqualColon ((:=:) _ _) = True
+    isColonEqualColon _ = False
+```
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/derive-is-data-con.cabal b/derive-is-data-con.cabal
new file mode 100644
--- /dev/null
+++ b/derive-is-data-con.cabal
@@ -0,0 +1,58 @@
+cabal-version: 2.2
+
+-- This file has been generated from package.yaml by hpack version 0.37.0.
+--
+-- see: https://github.com/sol/hpack
+
+name:           derive-is-data-con
+version:        0.1.0.0
+synopsis:       This package generates data constructor predicate functions
+description:    Please see the README on GitHub at <https://github.com/HaskellZhangSong/derive-is-data-con#readme>
+category:       Development
+homepage:       https://github.com/HaskellZhangSong/derive-is-data-con#readme
+bug-reports:    https://github.com/HaskellZhangSong/derive-is-data-con/issues
+author:         Zhang Song
+maintainer:     Haskell.Zhang.Song `at` hotmail.com
+copyright:      2025 Zhang Song
+license:        BSD-3-Clause
+license-file:   LICENSE
+build-type:     Simple
+extra-source-files:
+    README.md
+    CHANGELOG.md
+
+source-repository head
+  type: git
+  location: https://github.com/HaskellZhangSong/derive-is-data-con
+
+library
+  exposed-modules:
+      Data.Derive.IsDataCon
+  other-modules:
+      Paths_derive_is_data_con
+  autogen-modules:
+      Paths_derive_is_data_con
+  hs-source-dirs:
+      src
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints
+  build-depends:
+      base >=4.7 && <5
+    , template-haskell
+  default-language: Haskell2010
+
+test-suite derive-is-data-con-test
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  other-modules:
+      Cases
+      Paths_derive_is_data_con
+  autogen-modules:
+      Paths_derive_is_data_con
+  hs-source-dirs:
+      test
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wmissing-export-lists -Wmissing-home-modules -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      HUnit
+    , base >=4.7 && <5
+    , derive-is-data-con
+  default-language: Haskell2010
diff --git a/src/Data/Derive/IsDataCon.hs b/src/Data/Derive/IsDataCon.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Derive/IsDataCon.hs
@@ -0,0 +1,85 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE TemplateHaskell #-}
+module Data.Derive.IsDataCon (
+    derive_is
+    ) 
+where
+
+import Language.Haskell.TH
+import Control.Monad
+
+type TypeName = Name
+type ConName = Name
+
+nameToFunc :: ConName -> Int -> Dec
+nameToFunc name numOfTyArg = FunD fname [isClause, defaultClause]
+  where
+    fname = mkName $ "is" ++ ((if (isNameOp name) then (infixToStringName . mkName) else id) $ nameBase name)
+#if __GLASGOW_HASKELL__ >= 902
+    isClause = Clause [ConP name [] (replicate numOfTyArg WildP)] (NormalB (ConE 'True)) []
+#else
+    isClause = Clause [ConP name  (replicate numOfTyArg WildP)] (NormalB (ConE 'True)) []
+#endif
+    defaultClause = Clause [WildP] (NormalB (ConE 'False)) []
+
+infixToStringName :: Name -> String
+infixToStringName name = (concatMap charToString (nameBase name))
+
+isNameOp :: Name -> Bool
+isNameOp n = elem (head (nameBase n)) "~!@#$%^&*-+=|\\/<>:?.[]"
+
+charToString :: Char -> String
+charToString '~' = "Tilde"
+charToString '!' = "Bang"
+charToString '@' = "At"
+charToString '#' = "Hash"
+charToString '$' = "Dollar"
+charToString '%' = "Percent"
+charToString '^' = "Caret"
+charToString '&' = "And"
+charToString '*' = "Star"
+charToString '-' = "Minus"
+charToString '+' = "Plus"
+charToString '=' = "Equal"
+charToString '|' = "Pipe"
+charToString '\\' = "Backslash"
+charToString '/' = "Slash"
+charToString '<' = "Lt"
+charToString '>' = "Gt"
+charToString ':' = "Colon"
+charToString '?' = "Question"
+charToString '.' = "Dot"
+charToString x   = error $ show x ++ " is not a valid operator symbol"
+
+conToIsFunc :: Con -> [Dec]
+conToIsFunc (NormalC name ts)  = [nameToFunc name (length ts)]
+conToIsFunc (RecC name vbts)   = [nameToFunc name (length vbts)]
+conToIsFunc (InfixC _ name _)  = [nameToFunc name 2]
+conToIsFunc (ForallC _ _ con)  = conToIsFunc con
+conToIsFunc (GadtC ns ts _)    = map (uncurry nameToFunc) [(n, length ts) | n <- ns]
+conToIsFunc (RecGadtC ns ts _) = map (uncurry nameToFunc) [(n, length ts) | n <- ns]
+
+nameToSig :: ConName -> TypeName -> Int -> Q [Dec]
+nameToSig fn tn tnNumOfVars = do
+    ns <- replicateM tnNumOfVars (newName "a")
+    let vars = map VarT ns
+    let fname = mkName $ "is" ++ ((if (isNameOp fn) then (infixToStringName . mkName) else id) $ nameBase fn)
+    return [SigD fname (AppT (AppT ArrowT (foldl AppT (ConT tn) vars)) (ConT ''Bool))]
+
+conToSig :: TypeName -> Int -> Con -> Q [Dec]
+conToSig tn numOfTyVars (NormalC name _)  = nameToSig name tn numOfTyVars
+conToSig tn numOfTyVars (RecC name _)   = nameToSig name tn numOfTyVars
+conToSig tn numOfTyVars (InfixC _ name _)  = nameToSig name tn numOfTyVars
+conToSig tn numOfTyVars (ForallC _ _ con)  = conToSig tn numOfTyVars con
+conToSig tn numOfTyVars (GadtC ns _ _)    = fmap concat $ mapM (\fn -> nameToSig fn tn numOfTyVars) ns
+conToSig tn numOfTyVars (RecGadtC ns _ _) = fmap concat $ mapM (\fn -> nameToSig fn tn numOfTyVars) ns
+
+derive_is :: Name -> Q [Dec]
+derive_is name = do
+  info <- reify name
+  case info of
+    TyConI (DataD _ _ tvbs _ cons _) -> do 
+                                sigs <- fmap concat $ mapM (conToSig name (length tvbs)) cons
+                                let defs = concatMap conToIsFunc cons
+                                return $ sigs ++ defs
+    i -> error $ show i ++ " is not data type"
diff --git a/test/Cases.hs b/test/Cases.hs
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--- /dev/null
+++ b/test/Cases.hs
@@ -0,0 +1,79 @@
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TypeOperators #-}
+{-# OPTIONS_GHC -Wno-partial-fields #-}
+{-# OPTIONS_GHC -Wno-unused-top-binds #-}
+module Cases(
+    bool, maybe', either', op, gadtOp, recTest
+) where
+
+import Test.HUnit
+import Data.Derive.IsDataCon
+
+derive_is ''Bool
+
+bool :: Test
+bool = TestList [
+          TestCase (assertEqual "False is False"    (isFalse False) True)
+        , TestCase (assertEqual "True is True"      (isTrue True) True)
+        , TestCase (assertEqual "False is not True" (isFalse True) False)
+        , TestCase (assertEqual "True is not False" (isTrue False) False)
+    ]
+
+derive_is ''Maybe
+
+maybe' :: Test
+maybe' = TestList [
+         TestCase (assertEqual "Nothing is Nothing"  (isNothing Nothing) True)
+       , TestCase (assertEqual "Nothing is Nothing"  (isJust (Just ())) True)
+       , TestCase (assertEqual "Nothing is not Just" (isNothing (Just ())) False)
+       , TestCase (assertEqual "Just is not Nothing" (isJust Nothing) False)]
+
+derive_is ''Either
+
+either' :: Test
+either' = TestList [
+         TestCase (assertEqual "Left is Left" (isLeft (Left ())) True)
+       , TestCase (assertEqual "Right is Right" (isRight (Right ())) True)
+       , TestCase (assertEqual "Left is not Right" (isLeft (Right ())) False)
+       , TestCase (assertEqual "Right is not Left" (isRight (Left ())) False)]
+
+data (:-:) a b = (:-:) a b | (:=) a b
+derive_is ''(:-:)
+
+op :: Test
+op = TestList [
+         TestCase (assertEqual "ColonMinusColon is ColonMinusColon" (isColonMinusColon ((:-:) () ())) True)
+       , TestCase (assertEqual "ColonEqual is ColonEqual" (isColonEqual ( () := ())) True)
+       , TestCase (assertEqual "ColonMinusColon is not ColonEqual" (isColonMinusColon ((:=) () ())) False)
+       , TestCase (assertEqual "ColonEqual is not ColonMinusColon" (isColonEqual (() :-: ())) False)]
+
+
+data Gadt a b where
+    (:*:), (:=:)  :: a -> b -> Gadt a b
+
+derive_is ''Gadt
+
+gadtOp :: Test
+gadtOp = TestList [
+         TestCase (assertEqual "ColonStarColon is ColonStarColon" (isColonStarColon ((:*:) () ())) True)
+       , TestCase (assertEqual "ColonEqualColon is ColonEqualColon" (isColonEqualColon ( () :=: ())) True)
+       , TestCase (assertEqual "ColonStarColon is not ColonEqual" (isColonStarColon ((:=:) () ())) False)
+       , TestCase (assertEqual "ColonEqualColon is not ColonStarColon" (isColonEqualColon (() :*: ())) False)]
+
+data Rec a b c = A { getA :: a } | B { getB :: b } | C { getC :: c}
+
+derive_is ''Rec
+
+recTest :: Test
+recTest = TestList [
+         TestCase (assertEqual "A is A" (isA (A ())) True)
+       , TestCase (assertEqual "B is B" (isB (B ())) True)
+       , TestCase (assertEqual "C is C" (isC (C ())) True)
+       , TestCase (assertEqual "B is not A" (isA (B ())) False)
+       , TestCase (assertEqual "C is not A" (isA (C ())) False)
+       , TestCase (assertEqual "A is not B" (isB (A ())) False)
+       , TestCase (assertEqual "C is not B" (isB (C ())) False)
+       , TestCase (assertEqual "A is not C" (isC (A ())) False)
+       , TestCase (assertEqual "B is not C" (isC (B ())) False)
+  ]
diff --git a/test/Spec.hs b/test/Spec.hs
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--- /dev/null
+++ b/test/Spec.hs
@@ -0,0 +1,11 @@
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE TemplateHaskell #-}
+
+import Test.HUnit
+import Cases
+
+listTests :: [Test]
+listTests = [bool, maybe', either', op, gadtOp, recTest]
+
+main :: IO ()
+main = mapM_ runTestTT listTests