define expression

app/Main.hs

@@ -1,6 +1,4 @@
 module Main where
 
-import Lib
-
 main :: IO ()
-main = someFunc
+main = return ()

package.yaml

@@ -46,3 +46,4 @@ tests:
     - -with-rtsopts=-N
     dependencies:
     - typedMiniLang
+    - hspec

src/Expr.hs

@@ -0,0 +1,20 @@
+module Expr where
+
+type Variable = String
+
+data Expr =
+    EVar Variable
+    | ECBool Bool
+    | ECInt Int
+    | EAdd Expr Expr
+    | ESub Expr Expr
+    | EMul Expr Expr
+    | EDiv Expr Expr
+    | EAnd Expr Expr
+    | EOr Expr Expr
+    | ENot Expr
+    | ELT Expr Expr
+    | EEqInt Expr Expr
+    | EIf Expr Expr Expr
+    | ELet Variable Expr Expr
+    deriving (Show)

test/ExprSpec.hs

@@ -0,0 +1,7 @@
+module ExprSpec (spec) where
+
+import Test.Hspec
+import Expr
+
+spec :: Spec
+spec = return ()

test/Spec.hs

@@ -1,2 +1 @@
-main :: IO ()
-main = putStrLn "Test suite not yet implemented"
+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}