rescript-lang · glennsl · Oct 12, 2023 · Oct 30, 2023 · Oct 30, 2023 · aspeddro
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,6 +5,7 @@
 ### API changes
 
 - Add `Math.Int.floor` and `Math.Int.random`, https://github.com/rescript-association/rescript-core/pull/156
+- Add `protect` https://github.com/rescript-association/rescript-core/pull/155
 
 ### Documentation
 

diff --git a/src/RescriptCore.res b/src/RescriptCore.res
@@ -68,3 +68,29 @@ type undefined<+'a> = Js.undefined<'a>
 type nullable<+'a> = Js.nullable<'a>
 
 let panic = Core__Error.panic
+
+/**
+  `protect(~finally, f)`
+
+  Tries to execute the function `f`, and ensures that `finally` will be called
+  whether `f` raises an exception or not.
+
+  Any exception raised by `f` will be re-raised in order to be handled by the
+  user. If `finally` raises, then that exception will be emitted instead, and
+  any exception raised by `f` will go unnoticed.
+
+  ```res example
+  try protect(~finally=() => Js.log("finally"), () => failwith("oh no!")) catch {
+  | Failure(err) => Js.log(err)
+  }
+  ```
-  `protect(~finally, f)`
-
-  Tries to execute the function `f`, and ensures that `finally` will be called
-  whether `f` raises an exception or not.
-
-  Any exception raised by `f` will be re-raised in order to be handled by the
-  user. If `finally` raises, then that exception will be emitted instead, and
-  any exception raised by `f` will go unnoticed.
-
-  ```res example
-  try protect(~finally=() => Js.log("finally"), () => failwith("oh no!")) catch {
-  | Failure(err) => Js.log(err)
-  }
-  ```
+`protect(~finally, f)` tries to execute the function `f`, and ensures that 
+`finally` will be called whether `f` raises an exception or not.
+
+Any exception raised by `f` will be re-raised in order to be handled by the
+user. If `finally` raises, then that exception will be emitted instead, and
+any exception raised by `f` will go unnoticed.
+
+## Examples
+
+```rescript
+try protect(~finally=() => Console.log("finally"), () => panic("oh no!")) catch {
+| Failure(err) => Console.log(err)
+}
-  `protect(~finally, f)`
-
-  Tries to execute the function `f`, and ensures that `finally` will be called
-  whether `f` raises an exception or not.
-
-  Any exception raised by `f` will be re-raised in order to be handled by the
-  user. If `finally` raises, then that exception will be emitted instead, and
-  any exception raised by `f` will go unnoticed.
-
-  ```res example
-  try protect(~finally=() => Js.log("finally"), () => failwith("oh no!")) catch {
-  | Failure(err) => Js.log(err)
-  }
-  ```
+`protect(~finally, f)` tries to execute the function `f`, and ensures that 
+`finally` will be called whether `f` raises an exception or not.
+
+Any exception raised by `f` will be re-raised in order to be handled by the
+user. If `finally` raises, then that exception will be emitted instead, and
+any exception raised by `f` will go unnoticed.
+
+## Examples
+
+```rescript
+try protect(~finally=() => Console.log("finally"), () => panic("oh no!")) catch {
+| Failure(err) => Console.log(err)
+}
+*/
+let protect = (~finally, f) => {
+  let result = try f() catch {
+  | exn =>
+    finally()
+    raise(exn)
+  }
+  finally()
+  result
+}