Beginning haskell code

.kakrc

@@ -1,9 +1,10 @@
-hook -once -group eoc global KakBegin .* %{
-    repl-buffer-new racket -i
-    repl-buffer-send-text "(require xrepl)
-"
-%}
-
-define-command xrepl-enter %{
-    repl-buffer-send-text ",en %val{buffile}"
-}
+set global makecmd 'cabal build'
+#hook -once -group eoc global KakBegin .* %{
+#    repl-buffer-new racket -i
+#    repl-buffer-send-text "(require xrepl)
+#"
+#%}
+#
+#define-command xrepl-enter %{
+#    repl-buffer-send-text ",en %val{buffile}"
+#}

Main.hs

@@ -0,0 +1,46 @@
+module Main where
+
+import Data.Aeson (FromJSON, parseJSON, withObject, withText, (.:), decode)
+
+data Program = Program { programFns :: [Function] }
+    deriving (Show)
+
+data Function = Function {
+        functionName :: String,
+        returnType :: Maybe Type,
+        functionArgs :: [FunctionArg]
+    } deriving (Show)
+
+data Type = Int | Bool
+    deriving (Show)
+
+data FunctionArg = FunctionArg {
+        argName :: String,
+        argType :: Type
+    } deriving (Show)
+
+instance FromJSON Program  where
+    parseJSON = withObject "Program" $ \v -> Program
+        <$> v .: "functions"
+
+instance FromJSON Function where
+    parseJSON = withObject "Function" $ \v -> Function
+        <$> v .: "name"
+        <*> v .: "type"
+        <*> v .: "args"
+
+instance FromJSON FunctionArg where
+    parseJSON = withObject "FunctionArg" $ \v -> FunctionArg
+        <$> v .: "name"
+        <*> v .: "type"
+
+instance FromJSON Type where
+    parseJSON = withText "Type" $ \v ->
+        case v of
+             "int" -> return Int
+             "bool" -> return Bool
+             _ -> fail "wrong type"
+
+main :: IO ()
+main = do
+    putStrLn $ show (decode "int" :: Maybe Type)

Setup.hs

@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain

eoc.cabal

@@ -0,0 +1,28 @@
+cabal-version:       >=1.10
+-- Initial package description 'eoc.cabal' generated by 'cabal init'.  For
+-- further documentation, see http://haskell.org/cabal/users-guide/
+
+name:                eoc
+version:             0.1.0.0
+-- synopsis:
+-- description:
+-- bug-reports:
+-- license:
+license-file:        LICENSE
+author:              Enrico Lumetti
+maintainer:          enrico.lumetti@gmail.com
+-- copyright:
+-- category:
+build-type:          Simple
+extra-source-files:  README.md
+
+executable eoc
+  main-is:             Main.hs
+  -- other-modules:
+  -- other-extensions:
+  build-depends:
+      base >=4.13 && <4.14,
+      aeson >= 2.2
+  -- hs-source-dirs:
+  default-language:    Haskell2010
+  default-extensions: DeriveGeneric, OverloadedStrings