let expressions

1 files changed, 29 insertions, 0 deletions

diff --git a/discocaml/ast.ml b/discocaml/ast.ml
index 9436b69..025fa24 100644
--- a/discocaml/ast.ml
+++ b/discocaml/ast.ml
@@ -23,6 +23,7 @@ and expr =
   | Cons of expr index * expr index
   | Int of int
   | Lam of string * expr index
+  | Let of bool * string * expr index * expr index
   | Nil
   | Prim : 'a prim * 'a -> expr
   | Var of string
@@ -85,6 +86,20 @@ let add_expr_to_ast (ast : 'a ast) : Parsetree.expression -> expr index =
     | Pexp_ident { txt = Lident "-"; _ } -> binop Sub
     | Pexp_ident { txt = Lident "*"; _ } -> binop Mul
     | Pexp_ident { txt = Lident name; _ } -> add (Var name)
+    | Pexp_let
+        ( recursive,
+          [
+            {
+              pvb_pat = { ppat_desc = Ppat_var { txt = name; _ }; _ };
+              pvb_expr;
+              _;
+            };
+          ],
+          body ) ->
+        let recursive =
+          match recursive with Nonrecursive -> false | Recursive -> true
+        in
+        add (Let (recursive, name, loop pvb_expr, loop body))
     | _ -> raise_unsupported_expr expr
   in
   loop
@@ -154,6 +169,20 @@ let parsetree_of_subexpr (ast : 'a ast) : expr -> Parsetree.expression =
                None,
                Wrap.pattern (Ppat_var (Wrap.var x)),
                loop (subexpr b) ))
+    | Let (recursive, name, bound, body) ->
+        Wrap.expression
+          (Pexp_let
+             ( (if recursive then Recursive else Nonrecursive),
+               [
+                 {
+                   pvb_pat = Wrap.pattern (Ppat_var (Wrap.var name));
+                   pvb_expr = loop (subexpr bound);
+                   pvb_constraint = None;
+                   pvb_attributes = [];
+                   pvb_loc = Location.none;
+                 };
+               ],
+               loop (subexpr body) ))
     | Nil -> Wrap.expression (Pexp_construct (Wrap.ident "[]", None))
     | Prim (Add, (l, r)) ->
         Wrap.expression