app/Gyehoek/Sexp.hs

@@ -13,6 +13,8 @@ import Language.SexpGrammar.Generic
 import Data.InvertibleGrammar.Base qualified as IG
 import Data.InvertibleGrammar.Base ((:-)((:-)))
 import Data.List.NonEmpty (NonEmpty ((:|)))
+import Data.List (List)
+import GHC.Generics
 
 
 nonempty :: SexpGrammar a -> SexpGrammar (NonEmpty a)
@@ -31,3 +33,20 @@ let_ name rhs e = list (el (sym "let") >>> el bindings >>> el e)
     bindings = nonempty binding
     binding :: Grammar Position (Sexp :- t) ((_, _) :- t)
     binding = list (el name >>> el rhs) >>> pair
+
+data DotList a = MkDotList (NonEmpty a) a
+  deriving (Show, Generic)
+
+dotlist :: Grammar Position _ _ -> _
+dotlist x = list $ rest $ coproduct
+  [ x >>> iso _ _
+  ]
+
+lambda
+  :: (forall t. Grammar Position (Sexp :- t) (a :- t))
+  -> Grammar Position (Sexp :- List a :- t1) t2
+  -> Grammar Position (Sexp :- t1) t2
+lambda name e = list $
+  el (sym "lambda")
+  >>> el (list $ rest name)
+  >>> el e