Adds lists, although they don't evaluate yet.

1 files changed, 15 insertions, 0 deletions

diff --git a/discocaml/ast.ml b/discocaml/ast.ml
index 3ba3f63..f3606cf 100644
--- a/discocaml/ast.ml
+++ b/discocaml/ast.ml
@@ -20,8 +20,10 @@ type 'a prim =
 
 and expr =
   | App of expr index * expr index
+  | Cons of expr index * expr index
   | Int of int
   | Lam of string * expr index
+  | Nil
   | Prim : 'a prim * 'a -> expr
   | Var of string
 
@@ -70,6 +72,11 @@ let add_expr_to_ast (ast : 'a ast) : Parsetree.expression -> expr index =
             | _ -> raise_unsupported_expr expr)
           (loop f) xs
     | Pexp_constant (Pconst_integer (n, None)) -> add (Int (int_of_string n))
+    | Pexp_construct
+        ({ txt = Lident "::"; _ }, Some { pexp_desc = Pexp_tuple [ hd; tl ]; _ })
+      ->
+        add (Cons (loop hd, loop tl))
+    | Pexp_construct ({ txt = Lident "[]"; _ }, None) -> add Nil
     | Pexp_fun (Nolabel, None, arg_pat, body) -> (
         match arg_pat.ppat_desc with
         | Ppat_var { txt = name; _ } -> add (Lam (name, loop body))
@@ -131,6 +138,13 @@ let parsetree_of_subexpr (ast : 'a ast) : expr -> Parsetree.expression =
         let f, xs = list_of_apps expr in
         let xs = List.map (fun x -> (Asttypes.Nolabel, loop (subexpr x))) xs in
         Wrap.expression (Pexp_apply (loop f, xs))
+    | Cons (hd, tl) ->
+        Wrap.expression
+          (Pexp_construct
+             ( Wrap.ident "::",
+               Some
+                 (Wrap.expression
+                    (Pexp_tuple [ loop (subexpr hd); loop (subexpr tl) ])) ))
     | Int n ->
         Wrap.expression (Pexp_constant (Pconst_integer (Int.to_string n, None)))
     | Lam (x, b) ->
@@ -140,6 +154,7 @@ let parsetree_of_subexpr (ast : 'a ast) : expr -> Parsetree.expression =
                None,
                Wrap.pattern (Ppat_var (Wrap.var x)),
                loop (subexpr b) ))
+    | Nil -> Wrap.expression (Pexp_construct (Wrap.ident "[]", None))
     | Prim (Add, (l, r)) ->
         Wrap.expression
           (Pexp_apply