diff --git a/app/Compiler.hs b/app/Compiler.hs
new file mode 100644
index 0000000..8c7aee6
--- /dev/null
+++ b/app/Compiler.hs
@@ -0,0 +1,19 @@
+module Compiler where
+
+import qualified AbstractSyntaxTree as AST
+
+data Command = Const Int -- Load integer const
+             | Add
+             | Sub
+             | Mult
+             | Div
+             deriving Show
+
+compile :: AST.AST -> [Command]
+compile = reverse . compile'
+    where compile' ast = case ast of
+                    AST.Scalar i -> [Const i]
+                    AST.Operation AST.Add left right  -> Add : compile' left ++ compile' right
+                    AST.Operation AST.Sub left right  -> Sub : compile' left ++ compile' right
+                    AST.Operation AST.Mult left right -> Mult : compile' left ++ compile' right
+                    AST.Operation AST.Div left right  -> Div : compile' left ++ compile' right
diff --git a/app/Main.hs b/app/Main.hs
index 7d519fa..29032ec 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -3,10 +3,11 @@ module Main where
 import qualified Lexer
 import qualified Parser
 import qualified AbstractSyntaxTree as AST
+import qualified Compiler
 
 main :: IO ()
 main = do
   source <- readFile "arithmetic.txt"
   case Parser.parse $ Lexer.lex source of
-    Just source -> print $ AST.createAST source
+    Just source -> print $ Compiler.compile $ AST.createAST source
     _ -> putStr "Some error"
diff --git a/simple-arithmetic-compiler.cabal b/simple-arithmetic-compiler.cabal
index 7f36a32..bb577fe 100644
--- a/simple-arithmetic-compiler.cabal
+++ b/simple-arithmetic-compiler.cabal
@@ -52,7 +52,7 @@ executable simple-arithmetic-compiler
     main-is:          Main.hs
 
     -- Modules included in this executable, other than Main.
-    other-modules:    Lexer, Parser, AbstractSyntaxTree
+    other-modules:    Lexer, Parser, AbstractSyntaxTree, Compiler
 
     -- LANGUAGE extensions used by modules in this package.
     -- other-extensions: