wrap top-level statements in an async function

Summary:
When converting notebooks to Hack, put top-level statements in an `async` function.
This enables the use of `await` and matches how notebooks are type-checked and executed (as if top-level statements are in an async function).

context: https://fburl.com/source-controlled-notebooks-for-hack-project-2024

Reviewed By: lindseyjin

Differential Revision: D66460185

fbshipit-source-id: 10da589b8ffa20327f47cbc2b9e27a1093ec3a20

hphp/hack/src/notebook_convert/internal/hack_to_notebook.ml

@@ -101,7 +101,8 @@ let hack_to_notebook_exn
                   };
               _;
             }
-          when String.is_prefix ~prefix:"notebook_main"
+          when String.is_prefix
+                 ~prefix:Notebook_convert_constants.main_function_prefix
                @@ String.strip
                @@ Syn.text function_name ->
           Either.First (Syn.leading_text header, compound_statements)

hphp/hack/src/notebook_convert/internal/notebook_convert_constants.ml

@@ -0,0 +1,8 @@
+(*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the "hack" directory of this source tree.
+ *
+ *)
+let main_function_prefix = "gen_notebook_main_"

hphp/hack/src/notebook_convert/internal/notebook_convert_constants.mli

@@ -0,0 +1,8 @@
+(*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the "hack" directory of this source tree.
+ *
+ *)
+val main_function_prefix : string

hphp/hack/src/notebook_convert/internal/notebook_to_hack.ml

@@ -125,7 +125,8 @@ let hack_of_ipynb_exn
            block |> String.split_lines |> List.map ~f:(Printf.sprintf "    %s"))
     |> String.concat ~sep:"\n"
     |> Printf.sprintf
-         "function notebook_main_%s(): void {\n%s\n}"
+         "async function %s%s(): Awaitable<void> {\n%s\n}"
+         Notebook_convert_constants.main_function_prefix
          notebook_number
   in
   let unformatted =

hphp/hack/test/notebook_convert/hack_to_notebook/nb1.php

@@ -16,7 +16,7 @@ public function hello(): void {
   }
 }
 
-function notebook_main_n1234(): void {
+async function gen_notebook_main_n1234(): Awaitable<void> {
   //@bento-cell:{"cell_bento_metadata":{"output": {"id":1247934846418027,"loadingStatus":"loaded"}, "collapsed": true},"cell_type":"code","id":1}
   $m = new MyClass();
   echo "hi1";

hphp/hack/test/notebook_convert/hack_to_notebook/nb5.php

@@ -11,7 +11,7 @@
 test this is markdown
 */
 
-function notebook_main_N6203962(): void {
+async function gen_notebook_main_N6203962(): Awaitable<void> {
   //@bento-cell:{"id": 2, "cell_type": "code"}
   $a = 10;
   //@bento-cell:{"id": 4, "cell_type": "code"}

hphp/hack/test/notebook_convert/notebook_to_hack/nb1.tc.ipynb

@@ -46,7 +46,8 @@
       "metadata": {},
       "outputs": [],
       "source": [
-        "echo \"this is cell 4\";"
+        "echo \"this is cell 4\";\n",
+        "await (async () ==> {})();"
       ]
     }
   ],

hphp/hack/test/notebook_convert/notebook_to_hack/nb1.tc.ipynb.php

@@ -12,7 +12,7 @@ class MyClass {}
 I am a *markdown* **cell**
 */
 
-function notebook_main_N1234(): void {
+async function gen_notebook_main_N1234(): Awaitable<void> {
   //@bento-cell:{"cell_bento_metadata":{"collapsed":true,"output":{"id":1247934846418027,"loadingStatus":"loaded"}},"cell_type":"code","id":1}
   echo "hi from cell 1";
   //@bento-cell:{"cell_bento_metadata":{"collapsed":true,"output":{"id":1247934846418027,"loadingStatus":"loaded"}},"cell_type":"code","id":1}
@@ -25,4 +25,5 @@ function notebook_main_N1234(): void {
   echo "end of cell 2";
   //@bento-cell:{"cell_bento_metadata":{},"cell_type":"code","id":4}
   echo "this is cell 4";
+  await (async () ==> {})();
 }

hphp/hack/test/notebook_convert/notebook_to_hack/nb4_needs_hackfmt.tc.ipynb.php

@@ -2,7 +2,7 @@
 // copyright header here
 //@bento-notebook:{"notebook_number":"N1234","kernelspec":{"display_name":"hack","language":"hack","name":"bento_kernel_hack"}}
 
-function notebook_main_N1234(): void {
+async function gen_notebook_main_N1234(): Awaitable<void> {
   //@bento-cell:{"cell_bento_metadata":{"collapsed":true},"cell_type":"code","id":1}
   // ill-formatted code
   echo "hi0";

hphp/hack/test/notebook_convert/notebook_to_hack/nb5_has_syntax_errors_in_hack.ipynb.php

@@ -5,7 +5,7 @@
 class MyClass {}
 
 
-function notebook_main_N1234(): void {
+async function gen_notebook_main_N1234(): Awaitable<void> {
     //@bento-cell:{"cell_bento_metadata":{},"cell_type":"code","id":2}
     $x = new MyClass();
     // The next line is not valid Hack:

hphp/hack/test/notebook_convert/notebook_to_hack/nb6_no_hack_cells.ipynb.php

@@ -8,6 +8,6 @@
 I am a *markdown* **cell**
 */
 
-function notebook_main_N1234(): void {
+async function gen_notebook_main_N1234(): Awaitable<void> {
 
 }

hphp/hack/test/notebook_convert/notebook_to_hack/nb7_no_cells.ipynb.php

@@ -2,6 +2,6 @@
 // copyright header here
 //@bento-notebook:{"notebook_number":"N1234","kernelspec":{"display_name":"hack","language":"hack","name":"bento_kernel_hack"}}
 
-function notebook_main_N1234(): void {
+async function gen_notebook_main_N1234(): Awaitable<void> {
 
 }

hphp/hack/test/notebook_convert/notebook_to_hack/nb8_empty_cell_contents.ipynb.php

@@ -2,6 +2,6 @@
 // copyright header here
 //@bento-notebook:{"notebook_number":"N1234","kernelspec":{"display_name":"hack","language":"hack","name":"bento_kernel_hack"}}
 
-function notebook_main_N1234(): void {
+async function gen_notebook_main_N1234(): Awaitable<void> {
 
 }