compiler: forbid function redefinitions within ocaml module

Close #12

src/compiler/ocaml_to_erlang/error.ml

@@ -11,6 +11,15 @@ let ppf = Format.err_formatter
 let file_a_bug =
   {| If you think this is a bug, please file an issue here: https://github.com/AbstractMachinesLab/caramel/issues/new |}
 
+let redefining_function ~fn_name ~module_name =
+  Format.fprintf ppf
+    {|We have found 2 definitions of the function: %s in module %s, and this is unfortuantely not supported.
+\n
+|}
+    (Atom.to_string fn_name)
+    (Atom.to_string module_name);
+  exit 1
+
 let referenced_undeclared_function name =
   Format.fprintf ppf "Referencing undeclared function: %s" (Atom.to_string name);
   Format.fprintf ppf "\n\n%s" file_a_bug;

src/compiler/ocaml_to_erlang/fun.ml

@@ -48,7 +48,7 @@ let is_nested_module ~modules name =
     (fun Erlang.Ast.{ module_name = mn; _ } -> Atom.equal mn name)
     modules
 
-let find_function_arity_by_name ~functions name =
+let find_function_by_name ~functions name =
   List.find_opt
     (fun Erlang.Ast.{ fd_name; _ } -> Atom.equal fd_name name)
     functions
@@ -190,7 +190,7 @@ and mk_expression exp ~var_names ~modules ~functions ~module_name =
         | _ ->
             let name = Names.atom_of_longident txt in
             let arity =
-              match find_function_arity_by_name ~functions name with
+              match find_function_by_name ~functions name with
               | Some Erlang.Ast.{ fd_arity; _ } -> fd_arity
               | None -> 0
             in
@@ -365,11 +365,14 @@ and mk_expression exp ~var_names ~modules ~functions ~module_name =
 
 let mk_value vb ~modules ~functions ~module_name ~typedtree =
   match (vb.vb_pat.pat_desc, vb.vb_expr.exp_desc) with
-  | Tpat_var (id, _), Texp_function { cases; _ } ->
-      let id = id |> Names.atom_of_ident in
-      mk_function ~module_name ~modules ~functions
-        ~spec:(Typespecs.Fun.find_spec ~typedtree id)
-        ~var_names:[] id cases
+  | Tpat_var (id, _), Texp_function { cases; _ } -> (
+      let fn_name = id |> Names.atom_of_ident in
+      match find_function_by_name ~functions fn_name with
+      | Some _ -> Error.redefining_function ~fn_name ~module_name
+      | None ->
+          mk_function ~module_name ~modules ~functions
+            ~spec:(Typespecs.Fun.find_spec ~typedtree fn_name)
+            ~var_names:[] fn_name cases )
   | _ -> Error.unsupported_top_level_module_value ()
 
 (** Build the actual functions of an Erlang module

tests/compiler/functions.t/redefine.ml

@@ -0,0 +1,3 @@
+let f () = 1
+
+let f () = 1

tests/compiler/functions.t/run.t

@@ -7,61 +7,14 @@
   partial_functions.ml
   qualified_calls.ml
   qualified_calls_helper.ml
+  redefine.ml
   sequencing.ml
   uncurry.ml
   uncurry.mli
-  $ caramelc compile *.ml *.mli
-  File "partial_functions.ml", line 1, characters 9-21:
-  1 | let head (x :: _) = x
-               ^^^^^^^^^^^^
-  Warning 8: this pattern-matching is not exhaustive.
-  Here is an example of a case that is not matched:
-  []
-  File "partial_functions.ml", line 3, characters 9-23:
-  3 | let tail (_ :: xs) = xs
-               ^^^^^^^^^^^^^^
-  Warning 8: this pattern-matching is not exhaustive.
-  Here is an example of a case that is not matched:
-  []
-  File "partial_functions.ml", line 5, characters 11-20:
-  5 | let one_el [ x ] = x
-                 ^^^^^^^^^
-  Warning 8: this pattern-matching is not exhaustive.
-  Here is an example of a case that is not matched:
-  (_::_::_|[])
-  File "partial_functions.ml", line 7, characters 9-26:
-  7 | let at_2 (_ :: x :: _) = x
-               ^^^^^^^^^^^^^^^^^
-  Warning 8: this pattern-matching is not exhaustive.
-  Here is an example of a case that is not matched:
-  (_::[]|[])
-  File "partial_functions.ml", line 9, characters 9-31:
-  9 | let at_3 (_ :: _ :: x :: _) = x
-               ^^^^^^^^^^^^^^^^^^^^^^
-  Warning 8: this pattern-matching is not exhaustive.
-  Here is an example of a case that is not matched:
-  (_::_::[]|_::[]|[])
-  File "multiple_clauses.ml", line 1, characters 22-34:
-  1 | let iff_using_headers true f _ = f
-                            ^^^^^^^^^^^^
-  Warning 8: this pattern-matching is not exhaustive.
-  Here is an example of a case that is not matched:
-  false
-  Compiling uncurry.erl	OK
-  Compiling sequencing.erl	OK
-  Compiling qualified_calls_helper__nested.erl	OK
-  Compiling qualified_calls_helper.erl	OK
-  Compiling qualified_calls__nested.erl	OK
-  Compiling qualified_calls.erl	OK
-  Compiling partial_functions.erl	OK
-  Compiling multiple_clauses.erl	OK
-  Compiling labeled_arguments.erl	OK
-  Compiling ignored_arguments.erl	OK
-  Compiling hello_joe.erl	OK
+
+  $ caramelc compile basic.ml
   Compiling basic.erl	OK
-  $ echo $?
-  0
-  $ cat *.erl
+  $ cat basic.erl
   % Source code generated with Caramel.
   -module(basic).
 
@@ -79,6 +32,10 @@
   ignore() -> ok.
 
 
+
+  $ caramelc compile hello_joe.ml
+  Compiling hello_joe.erl	OK
+  $ cat hello_joe.erl
   % Source code generated with Caramel.
   -module(hello_joe).
 
@@ -90,6 +47,10 @@
     io:format(<<"~p">>, [Text | []]).
 
 
+
+  $ caramelc compile ignored_arguments.ml
+  Compiling ignored_arguments.erl	OK
+  $ cat ignored_arguments.erl
   % Source code generated with Caramel.
   -module(ignored_arguments).
 
@@ -111,6 +72,10 @@
   snd({_, B}) -> B.
 
 
+
+  $ caramelc compile labeled_arguments.ml
+  Compiling labeled_arguments.erl	OK
+  $ cat labeled_arguments.erl
   % Source code generated with Caramel.
   -module(labeled_arguments).
 
@@ -127,6 +92,16 @@
     erlang:'=:='(S1, S2).
 
 
+
+  $ caramelc compile multiple_clauses.ml
+  File "multiple_clauses.ml", line 1, characters 22-34:
+  1 | let iff_using_headers true f _ = f
+                            ^^^^^^^^^^^^
+  Warning 8: this pattern-matching is not exhaustive.
+  Here is an example of a case that is not matched:
+  false
+  Compiling multiple_clauses.erl	OK
+  $ cat multiple_clauses.erl
   % Source code generated with Caramel.
   -module(multiple_clauses).
 
@@ -157,6 +132,40 @@
     end.
 
 
+
+  $ caramelc compile partial_functions.ml
+  File "partial_functions.ml", line 1, characters 9-21:
+  1 | let head (x :: _) = x
+               ^^^^^^^^^^^^
+  Warning 8: this pattern-matching is not exhaustive.
+  Here is an example of a case that is not matched:
+  []
+  File "partial_functions.ml", line 3, characters 9-23:
+  3 | let tail (_ :: xs) = xs
+               ^^^^^^^^^^^^^^
+  Warning 8: this pattern-matching is not exhaustive.
+  Here is an example of a case that is not matched:
+  []
+  File "partial_functions.ml", line 5, characters 11-20:
+  5 | let one_el [ x ] = x
+                 ^^^^^^^^^
+  Warning 8: this pattern-matching is not exhaustive.
+  Here is an example of a case that is not matched:
+  (_::_::_|[])
+  File "partial_functions.ml", line 7, characters 9-26:
+  7 | let at_2 (_ :: x :: _) = x
+               ^^^^^^^^^^^^^^^^^
+  Warning 8: this pattern-matching is not exhaustive.
+  Here is an example of a case that is not matched:
+  (_::[]|[])
+  File "partial_functions.ml", line 9, characters 9-31:
+  9 | let at_3 (_ :: _ :: x :: _) = x
+               ^^^^^^^^^^^^^^^^^^^^^^
+  Warning 8: this pattern-matching is not exhaustive.
+  Here is an example of a case that is not matched:
+  (_::_::[]|_::[]|[])
+  Compiling partial_functions.erl	OK
+  $ cat partial_functions.erl
   % Source code generated with Caramel.
   -module(partial_functions).
 
@@ -182,6 +191,13 @@
   at_3([_ | [_ | [X | _]]]) -> X.
 
 
+
+  $ caramelc compile qualified_calls.ml qualified_calls_helper.ml
+  Compiling qualified_calls_helper__nested.erl	OK
+  Compiling qualified_calls_helper.erl	OK
+  Compiling qualified_calls__nested.erl	OK
+  Compiling qualified_calls.erl	OK
+  $ cat qualified_calls*.erl
   % Source code generated with Caramel.
   -module(qualified_calls).
 
@@ -242,6 +258,10 @@
   f(_x) -> ok.
 
 
+
+  $ caramelc compile sequencing.ml
+  Compiling sequencing.erl	OK
+  $ cat sequencing.erl
   % Source code generated with Caramel.
   -module(sequencing).
 
@@ -257,6 +277,10 @@
     io:format(<<"*micdrop*">>, []).
 
 
+
+  $ caramelc compile uncurry.ml uncurry.mli
+  Compiling uncurry.erl	OK
+  $ cat uncurry.erl
   % Source code generated with Caramel.
   -module(uncurry).
   -export_type([defer/1]).
@@ -284,3 +308,11 @@
   add_really_slow(X, ok, Y, ok) -> erlang:'+'(X, Y).
 
 
+
+  $ caramelc compile redefine.ml
+  We have found 2 definitions of the function: f in module redefine, and this is unfortuantely not supported.
+  \n
+  [1]
+  $ cat redefine.erl
+  cat: redefine.erl: No such file or directory
+  [1]