diff --git a/Main.hs b/Main.hs
index b6d1dab..c48ae35 100644
--- a/Main.hs
+++ b/Main.hs
@@ -2,70 +2,10 @@
 
 module Main where
 
-import Control.Applicative ((<|>),empty)
-import Data.Attoparsec.Text (Parser, parseOnly, decimal, choice, option, sepBy, endOfLine, endOfInput, many1)
-import qualified Data.Maybe as M
-import qualified Data.Text as T
+import Data.Attoparsec.Text (parseOnly)
 import qualified Data.Text.IO as T
 
-insuranceNetworkParser :: Parser InsuranceNetworkAST
-insuranceNetworkParser = many1 line
-  where
-    -- <line> ::= <insurer-id> ":" <percent> <optional-exprs>
-    -- <optional-exprs> ::= "" | "if" <exprs>
-    line :: Parser INASTLine
-    line = do
-      id <- insurerId
-      ": "
-      pc <- percent
-      oe <- option [] (" if " *> exprs)
-      endOfLine
-      pure $ INASTLine id pc oe
-    -- <exprs> ::= <expr> | <expr> "and" <exprs>
-    exprs :: Parser [ INASTExpr ]
-    exprs = expr `sepBy` " and "
-    -- <expr> ::= <lesser-than> | <greater-than> | <equals> | <insurer-id>
-    expr :: Parser INASTExpr
-    expr = choice [ INASTExprLt <$> lt
-                  , INASTExprGt <$> gt
-                  , INASTExprEq <$> eq
-                  , INASTExprInsurerId <$> insurerId ]
-    -- <lesser-than> ::= "<" <integer>
-    lt :: Parser INASTLt
-    lt = "<" *> integer
-    -- <greater-than> ::= ">" <integer>
-    gt :: Parser INASTGt
-    gt = ">" *> integer
-    -- <equals> ::= "=" <integer>
-    eq :: Parser INASTEq
-    eq = "=" *> integer
-    -- <insurer-id> ::= "I" <integer>
-    insurerId :: Parser INASTInsurerId
-    insurerId = "I" *> integer
-    -- <percent> ::= <integer> "%"
-    percent :: Parser INASTPercent
-    percent = integer <* "%"
-    -- <integer> ::= <digit> | <non-zero-digit> <integer>
-    -- Overapproximation of the grammar
-    integer :: Parser Int
-    integer = decimal
-
-type InsuranceNetworkAST = [INASTLine]
-
-data INASTLine = INASTLine INASTInsurerId INASTPercent [INASTExpr]
-  deriving (Show)
-
-data INASTExpr = INASTExprLt INASTLt
-               | INASTExprGt INASTGt
-               | INASTExprEq INASTEq
-               | INASTExprInsurerId INASTInsurerId
-  deriving (Show)
-
-type INASTLt = Int
-type INASTGt = Int
-type INASTEq = Int
-type INASTInsurerId = Int
-type INASTPercent = Int
+import INAST
 
 main :: IO ()
 main = do
@@ -74,5 +14,3 @@ main = do
   T.putStrLn inputNetwork
   T.putStrLn "Parsed AST:"
   print (parseOnly insuranceNetworkParser inputNetwork)
-
-
diff --git a/package.yaml b/package.yaml
index 8978128..67a78af 100644
--- a/package.yaml
+++ b/package.yaml
@@ -1,7 +1,20 @@
+name: in23
+
+ghc-options: -Wall -threaded
+
 dependencies:
   - base == 4.*
   - attoparsec
   - text
+
 executables:
-  interview-in:
+  in23:
     main: Main.hs
+    dependencies:
+      - in23
+
+library:
+  source-dirs: src
+  exposed-modules:
+    - INAST
+
diff --git a/src/INAST.hs b/src/INAST.hs
new file mode 100644
index 0000000..816a12c
--- /dev/null
+++ b/src/INAST.hs
@@ -0,0 +1,65 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# OPTIONS_GHC -Wno-unused-do-bind #-}
+
+module INAST where
+
+import Data.Attoparsec.Text (Parser, decimal, choice, option, sepBy, endOfLine, many1)
+
+insuranceNetworkParser :: Parser InsuranceNetworkAST
+insuranceNetworkParser = many1 line
+  where
+    -- <line> ::= <insurer-id> ":" <percent> <optional-exprs>
+    -- <optional-exprs> ::= "" | "if" <exprs>
+    line :: Parser INASTLine
+    line = do
+      id' <- insurerId
+      ": "
+      pc <- percent
+      oe <- option [] (" if " *> exprs)
+      endOfLine
+      pure $ INASTLine id' pc oe
+    -- <exprs> ::= <expr> | <expr> "and" <exprs>
+    exprs :: Parser [ INASTExpr ]
+    exprs = expr `sepBy` " and "
+    -- <expr> ::= <lesser-than> | <greater-than> | <equals> | <insurer-id>
+    expr :: Parser INASTExpr
+    expr = choice [ INASTExprLt <$> lt
+                  , INASTExprGt <$> gt
+                  , INASTExprEq <$> eq
+                  , INASTExprInsurerId <$> insurerId ]
+    -- <lesser-than> ::= "<" <integer>
+    lt :: Parser INASTLt
+    lt = "<" *> integer
+    -- <greater-than> ::= ">" <integer>
+    gt :: Parser INASTGt
+    gt = ">" *> integer
+    -- <equals> ::= "=" <integer>
+    eq :: Parser INASTEq
+    eq = "=" *> integer
+    -- <insurer-id> ::= "I" <integer>
+    insurerId :: Parser INASTInsurerId
+    insurerId = "I" *> integer
+    -- <percent> ::= <integer> "%"
+    percent :: Parser INASTPercent
+    percent = integer <* "%"
+    -- <integer> ::= <digit> | <non-zero-digit> <integer>
+    -- Overapproximation of the grammar
+    integer :: Parser Int
+    integer = decimal
+
+type InsuranceNetworkAST = [INASTLine]
+
+data INASTLine = INASTLine INASTInsurerId INASTPercent [INASTExpr]
+  deriving (Show)
+
+data INASTExpr = INASTExprLt INASTLt
+               | INASTExprGt INASTGt
+               | INASTExprEq INASTEq
+               | INASTExprInsurerId INASTInsurerId
+  deriving (Show)
+
+type INASTLt = Int
+type INASTGt = Int
+type INASTEq = Int
+type INASTInsurerId = Int
+type INASTPercent = Int