feat: parse an application

2 files changed, 13 insertions, 6 deletions

diff --git a/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs b/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs
index e60d761..f18ac74 100644
--- a/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs
+++ b/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs
@@ -13,7 +13,7 @@ type Parser = Parsec Void Text
 data ParseError = ParseError Text
   deriving (Eq, Show)
 
-data AST = Sym Text | Abs [Text] AST | App AST AST
+data AST = Sym Text | Abs [Text] AST | App AST AST [AST]
   deriving (Eq, Show)
 
 parse :: Text -> Either ParseError AST
@@ -28,7 +28,7 @@ app =
   between
     lpar
     rpar
-    (App <$> ast <*> ast)
+    (App <$> ast <*> ast <*> many ast)
 
 lambda :: Parser AST
 lambda =
diff --git a/lambda-calcul/haskell/test/Minilang/Lambda/ParserSpec.hs b/lambda-calcul/haskell/test/Minilang/Lambda/ParserSpec.hs
index b52017a..13279e9 100644
--- a/lambda-calcul/haskell/test/Minilang/Lambda/ParserSpec.hs
+++ b/lambda-calcul/haskell/test/Minilang/Lambda/ParserSpec.hs
@@ -5,7 +5,7 @@ import qualified Data.Text as Text
 import Minilang.Lambda.Parser (AST (..), initialChars, parse, restChars)
 import Test.Hspec (Spec, parallel, shouldBe)
 import Test.Hspec.QuickCheck (prop)
-import Test.QuickCheck (Arbitrary (..), NonEmptyList (..), elements, listOf)
+import Test.QuickCheck (Arbitrary (..), NonEmptyList (..), elements, listOf, (==>))
 
 spec :: Spec
 spec = parallel $ do
@@ -17,11 +17,18 @@ spec = parallel $ do
 
   prop "parses a lambda-expression with multiple bindings as an abstraction" $ \(NonEmpty idents) (Identifier body) ->
     let vars = unIdent <$> idents
-        nestedAbs = Abs vars (Sym body)
-     in parse ("(lam (" <> Text.unwords vars <> ") " <> body <> ")") `shouldBe` Right nestedAbs
+        abs = Abs vars (Sym body)
+     in parse ("(lam (" <> Text.unwords vars <> ") " <> body <> ")") `shouldBe` Right abs
 
   prop "parses an application" $ \(Identifier ident1) (Identifier ident2) ->
-    parse ("(" <> ident1 <> " " <> ident2 <> ")") `shouldBe` Right (App (Sym ident1) (Sym ident2))
+    parse ("(" <> ident1 <> " " <> ident2 <> ")") `shouldBe` Right (App (Sym ident1) (Sym ident2) [])
+
+  prop "parses multiple applications" $ \(NonEmpty idents) ->
+    (length idents >= 2) ==>
+      let vars = unIdent <$> idents
+          (a : b : rest) = vars
+          app = App (Sym a) (Sym b) (Sym <$> rest)
+       in parse ("(" <> Text.unwords vars <> ")") `shouldBe` Right app
 
 newtype Identifier = Identifier {unIdent :: Text}
   deriving (Eq, Show)