feat: Add high-level parse function to Parser

app/Main.hs

@@ -1,8 +1,9 @@
 module Main where
 
 import qualified Lexer
+import qualified Parser
 
 main :: IO ()
 main = do
   source <- readFile "arithmetic.txt"
-  putStr $ show (Lexer.lex source)
+  putStr $ show (Parser.parse $ Lexer.lex source)

app/Parser.hs

@@ -4,7 +4,7 @@ import qualified Lexer as L
 import Control.Applicative as Applicative
 import Data.Void as Void
 
-type AST = Expr
+type CST = Expr
 
 data Expr = Add Term Expr
           | Sub Term Expr
@@ -46,6 +46,12 @@ instance Alternative Parser where
         result -> result
 
 
+parse :: Tokens -> Maybe CST
+parse tokens = case runParser parseExpression tokens of
+    Just ([], cst) -> Just cst
+    _ -> Nothing
+
+
 parseAdd :: Parser Expr
 parseAdd = liftA2 Add (parseTerm <* expect L.Plus) parseExpression