Require imports to be specified without file extension

design/DFX-Interface.md

@@ -138,6 +138,7 @@ prints to the standard output all URLs _directly_ imported by
    mo:other_package/Some/Module
    ic:ABCDE01A7
    ic:alias
+   relative/path
 
 This _reads_ only `some/path/input.mo`, and writes no files.
 

samples/ListClient.mo

@@ -1,4 +1,4 @@
-import List = "ListLib.mo"; // private, so we don't re-export List
+import List = "ListLib"; // private, so we don't re-export List
 
 module {
 

samples/app/client.mo

@@ -1,5 +1,5 @@
 import Prim "mo:prim";
-import S "server.mo";
+import S "server";
 
 actor class Client() = this {
   // TODO: these should be constructor params once we can compile them

samples/app/main.mo

@@ -1,5 +1,5 @@
-import Server "server.mo";
-import Client "client.mo";
+import Server "server";
+import Client "client";
 
 let server = Server.Server();
 let bob = Client.Client();

samples/app/server.mo

@@ -1,6 +1,6 @@
 import Prim "mo:prim";
-import L "list.mo";
-import T "types.mo";
+import L "list";
+import T "types";
 
 type ClientData = {
   id : Nat;

src/languageServer/completion.ml

@@ -134,7 +134,7 @@ let completions index logger project_root file_path file_contents line column =
      let current_module_decls =
        current_uri_opt
        |> opt_bind (fun uri -> DI.lookup_module uri index)
-       |> Fun.flip Lib.Option.get [] in
+       |> Option.fold ~none:[] ~some:snd in
      current_module_decls
   in
   let module_alias_completion_item alias =
@@ -165,7 +165,7 @@ let completions index logger project_root file_path file_contents line column =
      match module_path with
      | Some mp ->
         (match DI.lookup_module (snd mp) index with
-         | Some decls ->
+         | Some (_, decls) ->
             decls
             |> List.filter (has_prefix prefix)
             |> List.map item_of_ide_decl

src/languageServer/completion_test.ml

@@ -77,7 +77,7 @@ List.|
 let%test "it handles a full module" =
   prefix_test_case
 {|module {
-  private import List = "./ListLib.mo";
+  private import List = "./ListLib";
 
   func singleton<T>(x: T): List.List<T> =
     List.cons<T>(x, Test.|<T>());
@@ -89,8 +89,8 @@ let%test "it handles a full module" =
 let%test "it doesn't fall through to the next valid prefix" =
   prefix_test_case
 {|module {
-private import List = "lib/ListLib.mo"; // private, so we don't re-export List
-private import ListFns = "lib/ListFuncs.mo"; // private, so we don't re-export List
+private import List = "lib/ListLib"; // private, so we don't re-export List
+private import ListFns = "lib/ListFuncs"; // private, so we don't re-export List
 type Stack = List.List<Int>;
 func push(x : Int, s : Stack) : Stack = List.cons<Int>(x, s);
 func empty():Stack = List.nil<Int>();

src/languageServer/declaration_index.ml

@@ -65,20 +65,32 @@ let add_module : string -> ide_decl list -> declaration_index -> declaration_ind
 let lookup_module
       (path : string)
       (index : t)
-    : ide_decl list option =
+    : (string * ide_decl list) option =
   let open Pipeline.URL in
   let make_absolute = Lib.FilePath.make_absolute (Sys.getcwd ()) in
   match parse path with
   | Ok (Relative path) ->
+     let path =
+       Pipeline.ResolveImport.append_extension Sys.file_exists path
+       |> Option.value ~default:path in
      Index.find_opt (make_absolute path) index.modules
+     |> Option.map (fun decls -> (path, decls))
   | Ok (Package (pkg, path)) ->
      Option.bind
        (Flags.M.find_opt pkg index.package_map)
        (fun pkg_path ->
+         let path =
+           Pipeline.ResolveImport.append_extension
+             Sys.file_exists (Filename.concat pkg_path path)
+           |> Option.value ~default:path in
          Index.find_opt
-           (make_absolute (Filename.concat pkg_path path))
-           index.modules)
-  | Ok Prim -> Index.find_opt "@prim" index.modules
+           (make_absolute path)
+           index.modules
+         |> Option.map (fun decls -> (path, decls))
+       )
+  | Ok Prim ->
+     Index.find_opt "@prim" index.modules
+     |> Option.map (fun decls -> ("@prim", decls))
   | Ok (Ic _ | IcAlias _) -> (* TODO *) None
   | Error _ -> None
 

src/languageServer/declaration_index.mli

@@ -24,6 +24,6 @@ type ide_decl =
 val string_of_ide_decl : ide_decl -> string
 val name_of_ide_decl : ide_decl -> string
 
-val lookup_module : string -> t -> ide_decl list option
+val lookup_module : string -> t -> (string * ide_decl list) option
 
 val make_index : (string -> string -> unit) -> Vfs.t -> string list -> t Diag.result

src/languageServer/definition.ml

@@ -12,7 +12,11 @@ let range_of_region (at : Source.region) : Lsp.range = Lsp.
     range_end_ = position_of_pos at.Source.right;
   }
 
-let find_named (name : string) : DI.ide_decl list -> Source.region option =
+let find_named
+    : string ->
+      (string * DI.ide_decl list) ->
+      (string * Source.region) option =
+  fun name (path, decls) ->
   Lib.List.first_opt (function
     | DI.ValueDecl value ->
         if String.equal value.DI.name name
@@ -21,7 +25,8 @@ let find_named (name : string) : DI.ide_decl list -> Source.region option =
     | DI.TypeDecl typ ->
         if String.equal typ.DI.name name
         then typ.DI.definition
-        else None)
+        else None) decls
+  |> Option.map (fun x -> (path, x))
 
 let opt_bind f = function
   | Some x -> f x
@@ -47,13 +52,11 @@ let definition_handler
        | Resolved resolved ->
           DI.lookup_module resolved.path index
           |> opt_bind (find_named resolved.ident)
-          |> Option.map (fun loc -> (resolved.path, loc))
        | Ident ident ->
           Lib.FilePath.relative_to project_root file_path
           |> opt_bind (fun uri ->
               DI.lookup_module uri index
               |> opt_bind (find_named ident)
-              |> Option.map (fun loc -> (uri, loc))
       )) in
   let location =
     Option.map (fun (path, region) ->

src/languageServer/hover.ml

@@ -26,7 +26,7 @@ let hover_handler
      let current_module_decls =
        current_uri_opt
        |> Fun.flip Option.bind (fun uri -> lookup_module uri index)
-       |> Fun.flip Lib.Option.get [] in
+       |> Option.fold ~none:[] ~some:snd in
      current_module_decls in
   let mk_hover_result ide_decl =
     Lsp.{ hover_result_contents = markup_content (hover_detail ide_decl) } in
@@ -42,7 +42,7 @@ let hover_handler
            Some Lsp.{ hover_result_contents = markup_content path }
         | Source_file.Resolved resolved ->
            lookup_module resolved.Source_file.path index
-           |> Fun.flip Option.bind (fun decls ->
+           |> Fun.flip Option.bind (fun (_, decls) ->
                 List.find_opt
                   (fun d -> name_of_ide_decl d = resolved.Source_file.ident)
                   decls)

src/languageServer/source_file.ml

@@ -6,6 +6,10 @@ type cursor_target =
    | CIdent of string
    | CQualified of string * string
 
+let string_of_cursor_target = function
+  | CIdent i -> "(CIdent " ^ i ^ ")"
+  | CQualified (q, i) -> "CQUalified (" ^ q ^ ", " ^ i ^ ")"
+
 let cursor_target_at_pos
     (position : Lsp.position)
     (file_contents : string)
@@ -118,7 +122,7 @@ let identifier_at_pos project_root file_path file_contents position =
       file_path
       file_contents in
   cursor_target_at_pos position file_contents
-    |> Option.map (function
+  |> Option.map (function
         | CIdent s ->
            (match List.find_opt (fun (alias, _) -> alias = s) imported with
             | None -> Ident s

src/languageServer/source_file_tests.ml

@@ -67,8 +67,8 @@ let%test "it parses a simple module header" =
   parse_module_header_test_case
     "/project"
     "/project/src/Main.mo"
-    "import P \"lib/prelude.mo\""
-    ["P", "src/lib/prelude.mo"]
+    "import P \"lib/prelude\""
+    ["P", "src/lib/prelude"]
 
 let%test "it parses a simple module header that contains a prim import" =
   parse_module_header_test_case
@@ -81,8 +81,8 @@ let%test "it parses a simple module header with package paths" =
   parse_module_header_test_case
     "/project"
     "/project/src/Main.mo"
-    "import P \"mo:stdlib/prelude.mo\""
-    ["P", "mo:stdlib/prelude.mo"]
+    "import P \"mo:stdlib/prelude\""
+    ["P", "mo:stdlib/prelude"]
 
 let%test "it parses a simple module header" =
   parse_module_header_test_case
@@ -91,8 +91,8 @@ let%test "it parses a simple module header" =
     {|
 module {
 
-private import List "lib/ListLib.mo";
-private import ListFuncs "lib/ListFuncs.mo";
+private import List "lib/ListLib";
+private import ListFuncs "lib/ListFuncs";
 
 type Stack = List.List<Int>;
 
@@ -106,6 +106,6 @@ func singleton(x: Int): Stack =
   ListFuncs.doubleton<Int>(x, x);
 }
 |}
-    [ ("List", "lib/ListLib.mo")
-    ; ("ListFuncs", "lib/ListFuncs.mo")
+    [ ("List", "lib/ListLib")
+    ; ("ListFuncs", "lib/ListFuncs")
     ]

src/pipeline/resolve_import.ml

@@ -47,10 +47,16 @@ type package_map = filepath M.t
 open Syntax
 open Source
 
-let append_lib_if_needed f =
-  if Sys.file_exists f && Sys.is_directory f
-  then Filename.concat f "lib.mo"
-  else f
+let append_extension file_exists f =
+  if Option.is_some (Lib.String.chop_suffix "/" f) then
+    Some (Filename.concat f "lib.mo")
+  else if Filename.extension f = "" then
+    if file_exists (f ^ ".mo") then
+      Some (f ^ ".mo")
+    else
+      Some (Filename.concat f "lib.mo")
+  else
+    None
 
 let err_unrecognized_url msgs at url msg =
   let open Diag in
@@ -88,6 +94,15 @@ let err_file_does_not_exist msgs at full_path =
       text = Printf.sprintf "file \"%s\" does not exist" full_path
     }
 
+let err_import_musnt_have_extension msgs at full_path =
+  let open Diag in
+  add_msg msgs {
+    sev = Error;
+    at;
+    cat = "import";
+    text = Printf.sprintf "an import must not have an extension, try importing %s as %s instead" full_path (Filename.chop_extension full_path)
+  }
+
 let err_package_not_defined msgs at pkg =
   let open Diag in
   add_msg msgs {
@@ -135,13 +150,17 @@ let err_prim_pkg msgs =
   }
 
 let add_lib_import msgs imported ri_ref at full_path =
-  let full_path = append_lib_if_needed full_path in
-  if Sys.file_exists full_path
-  then begin
-    ri_ref := LibPath full_path;
-    imported := RIM.add (LibPath full_path) at !imported
-  end else
-    err_file_does_not_exist msgs at full_path
+  match append_extension Sys.file_exists full_path with
+  | Some full_path ->
+     if Sys.file_exists full_path
+     then begin
+         ri_ref := LibPath full_path;
+         imported := RIM.add (LibPath full_path) at !imported
+       end else
+       err_file_does_not_exist msgs at full_path
+  | None ->
+       err_import_musnt_have_extension msgs at full_path
+
 
 let add_idl_import msgs imported ri_ref at full_path bytes =
   if Sys.file_exists full_path

src/pipeline/resolve_import.mli

@@ -31,3 +31,6 @@ type resolved_flags = {
 val resolve_flags : flags -> resolved_flags Diag.result
 
 val resolve : flags -> Syntax.prog -> filepath -> resolved_imports Diag.result
+
+(* Exported for tests *)
+val append_extension : (filepath -> bool) -> filepath -> filepath option

src/pipeline/resolve_import_test.ml

@@ -0,0 +1,25 @@
+(** Given a list of filenames that should be reported as existing
+   tests what a given import path resolves to *)
+let import_relative_test_case files import expected =
+  let actual = Resolve_import.append_extension (fun x -> List.mem x files) import in
+  let show = function
+    | None -> "None"
+    | Some s -> "Some " ^ s in
+  Option.equal String.equal actual expected ||
+    (Printf.printf
+       "\nExpected: %s\nActual:   %s\n"
+       (show expected)
+       (show actual);
+     false)
+
+let%test "it resolves a relative file import" =
+  import_relative_test_case ["list.mo"] "list" (Some "list.mo")
+
+let%test "it resolves a relative directory import" =
+  import_relative_test_case [] "list/" (Some "list/lib.mo")
+
+let%test "it resolves to a relative directory import if no .mo file is found" =
+  import_relative_test_case [] "list" (Some "list/lib.mo")
+
+let%test "it fails on a relative import with an extension" =
+  import_relative_test_case [] "list.mo" None

stdlib/examples/actorspec/demo/Demo.mo

@@ -1,4 +1,4 @@
-import ActorSpec "../src/ActorSpec.mo";
+import ActorSpec "../src/ActorSpec";
 
 type Group = ActorSpec.Group;
 

stdlib/examples/actorspec/src/ActorSpec.mo

@@ -1,7 +1,7 @@
-import Debug "mo:stdlib/debug.mo";
-import Array "mo:stdlib/array.mo";
-import Int "mo:stdlib/int.mo";
-import Text "mo:stdlib/text.mo";
+import Debug "mo:stdlib/debug";
+import Array "mo:stdlib/array";
+import Int "mo:stdlib/int";
+import Text "mo:stdlib/text";
 
 module {
   public type Group = {

stdlib/examples/produce-exchange/src/docTable.mo

@@ -1,6 +1,6 @@
-import Hash "mo:stdlib/hash.mo";
+import Hash "mo:stdlib/hash";
 
-import Trie "mo:stdlib/trie.mo";
+import Trie "mo:stdlib/trie";
 
 module {
 /**

stdlib/examples/produce-exchange/src/serverActor.mo

@@ -4,16 +4,16 @@
  --------------------
 */
 
-import Debug "mo:stdlib/debug.mo";
-import P = "mo:stdlib/prelude.mo";
-import Option = "mo:stdlib/option.mo";
-import T = "serverTypes.mo";
-import L = "serverLang.mo";
-import Model = "serverModel.mo";
-import Result = "mo:stdlib/result.mo";
-
-import Trie = "mo:stdlib/trie.mo";
-import List = "mo:stdlib/list.mo";
+import Debug "mo:stdlib/debug";
+import P = "mo:stdlib/prelude";
+import Option = "mo:stdlib/option";
+import T = "serverTypes";
+import L = "serverLang";
+import Model = "serverModel";
+import Result = "mo:stdlib/result";
+
+import Trie = "mo:stdlib/trie";
+import List = "mo:stdlib/list";
 
 type List<T> = List.List<T>;
 

stdlib/examples/produce-exchange/src/serverLang.mo

@@ -1,5 +1,5 @@
-import Result = "mo:stdlib/result.mo";
-import T = "serverTypes.mo";
+import Result = "mo:stdlib/result";
+import T = "serverTypes";
 
 
 module {