parse constructor expression

lib/syntax/parser.mly

@@ -134,7 +134,10 @@ type_expr:
 
 expr:
     | c=constant { EConst c }
+    | p=path DOT v=IDENT { EField (p, v) }
+    | p=path DOT v=MIDENT { EFieldCons (p, v) }
     | v=IDENT { EVar v }
+    | c=MIDENT { ECons c }
     | LET p=pattern EQ e1=expr IN e2=expr { ELet (p, e1, e2) }
     | LET REC binds=separated_nonempty_list(AND, function_bind) IN body=expr { ELetrec (binds, body) }
     | tu=tuple_expr { tu }

lib/syntax/parsetree.ml

@@ -36,6 +36,7 @@ and constant =
 and expr =
   | EConst of constant
   | EVar of string
+  | ECons of string
   | ELet of pattern * expr * expr
   | ELetrec of (string * lambda) list * expr
   | ELam of lambda
@@ -45,6 +46,7 @@ and expr =
   | EAnn of expr * type_expr
   | ETuple of expr list
   | EField of path * string
+  | EFieldCons of path * string
 
 and lambda = para * expr
 

lib/test/parse_test.ml

@@ -39,7 +39,14 @@ let%expect_test "Test: expression parsing" =
     (ELetrec
       ((odd ((PBare x) (EApp (EVar even) (EVar x))))
         (even ((PAnn x (TCons int ())) (EApp (EVar odd) (EVar x)))))
-      (EApp (EVar odd) (EConst (CInt 1)))) |}]
+      (EApp (EVar odd) (EConst (CInt 1)))) |}];
+  print_parsed {|E.f y|};
+  [%expect {| (EApp (EField (PName E) f) (EVar y)) |}];
+  print_parsed {|Cons (x, y)|};
+  [%expect {| (EApp (ECons Cons) (ETuple ((EVar x) (EVar y)))) |}];
+  print_parsed {|L.Cons (x, y)|};
+  [%expect
+    {| (EApp (EFieldCons (PName L) Cons) (ETuple ((EVar x) (EVar y)))) |}]
 
 let%expect_test "Test: full program parsing" =
   print_parsed_program {|let x = 1|};

lib/typing/check.ml

@@ -65,6 +65,8 @@ let rec type_check (e : T.expr) (env : Env.t) : expr * U.t =
   | T.EAnn (e, te) -> tc_ann e te
   | T.ETuple es -> tc_tuple es
   | T.EField (p, x) -> tc_field p x
+  | T.ECons _ -> failwith ""
+  | T.EFieldCons _ -> failwith ""
 
 and tc_const c =
   match c with