From e300c0fdf63e7fa7bd58c1696494fa108e260ac4 Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Sun, 19 Feb 2023 15:38:14 +0100
Subject: [PATCH 01/12] feat(option): add flat

---
 src/Core__Option.mjs  |  8 ++++++++
 src/Core__Option.res  |  6 ++++++
 src/Core__Option.resi | 12 ++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/src/Core__Option.mjs b/src/Core__Option.mjs
index 29ad429b..d886ed3b 100644
--- a/src/Core__Option.mjs
+++ b/src/Core__Option.mjs
@@ -3,6 +3,13 @@
 import * as Curry from "rescript/lib/es6/curry.js";
 import * as Caml_option from "rescript/lib/es6/caml_option.js";
 
+function flat(opt) {
+  if (opt !== undefined) {
+    return Caml_option.valFromOption(opt);
+  }
+  
+}
+
 function filter(opt, p) {
   var p$1 = Curry.__1(p);
   if (opt !== undefined && p$1(Caml_option.valFromOption(opt))) {
@@ -107,6 +114,7 @@ function cmp(a, b, f) {
 }
 
 export {
+  flat ,
   filter ,
   forEach ,
   getExn ,
diff --git a/src/Core__Option.res b/src/Core__Option.res
index 9b688647..2dcb2922 100644
--- a/src/Core__Option.res
+++ b/src/Core__Option.res
@@ -22,6 +22,12 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
 
+let flat = opt =>
+  switch opt {
+  | Some(v) => v
+  | None => None
+  }
+
 let filterU = (opt, p) =>
   switch opt {
   | Some(x) as some if p(. x) => some
diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index fb3c8a46..e4ef6870 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -39,6 +39,18 @@ let someString: option<string> = Some("hello")
 ```
 */
 
+/**
+`flat(value)` flattens a nested `option` value to a single level..
+
+## Examples
+
+```rescript
+Option.float(Some(Some(10))) // Some(10)
+Option.flat(Some(None)) // None
+```
+*/
+let flat: option<option<'a>> => option<'a>
+
 /**
 `filter(opt, f)` applies `f` to `opt`, if `f` returns `true`, then it returns `Some(value)`, otherwise returns `None`.
 

From 2c1d16b3e972254e0ca44c854eeb8a6058e15fe5 Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Sun, 19 Feb 2023 15:52:33 +0100
Subject: [PATCH 02/12] feat(option): add expect

---
 src/Core__Option.mjs  | 12 ++++++++++++
 src/Core__Option.res  |  6 ++++++
 src/Core__Option.resi | 14 ++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/src/Core__Option.mjs b/src/Core__Option.mjs
index d886ed3b..4a036610 100644
--- a/src/Core__Option.mjs
+++ b/src/Core__Option.mjs
@@ -36,6 +36,17 @@ function getExn(x) {
       };
 }
 
+function expect(opt, message) {
+  if (opt !== undefined) {
+    return Caml_option.valFromOption(opt);
+  }
+  throw {
+        RE_EXN_ID: "Failure",
+        _1: message,
+        Error: new Error()
+      };
+}
+
 function mapWithDefault(opt, $$default, f) {
   var f$1 = Curry.__1(f);
   if (opt !== undefined) {
@@ -118,6 +129,7 @@ export {
   filter ,
   forEach ,
   getExn ,
+  expect ,
   mapWithDefault ,
   map ,
   flatMap ,
diff --git a/src/Core__Option.res b/src/Core__Option.res
index 2dcb2922..90d03a41 100644
--- a/src/Core__Option.res
+++ b/src/Core__Option.res
@@ -50,6 +50,12 @@ let getExn = x =>
   | None => raise(Not_found)
   }
 
+let expect = (opt, message) =>
+  switch opt {
+  | Some(value) => value
+  | None => raise(Failure(message))
+  }
+
 external getUnsafe: option<'a> => 'a = "%identity"
 
 let mapWithDefaultU = (opt, default, f) =>
diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index e4ef6870..1e5bf6e8 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -91,6 +91,20 @@ Option.getExn(None) /* Raises an Error */
 */
 let getExn: option<'a> => 'a
 
+/**
+`expect(opt, message)` returns `value` if `Some(value)`, raises a `Failure` expection with the given message if `None`.
+
+```rescript
+Option.expect(Some(3), "should not be None") // 3
+Option.expect(None, "should not be None") // Raises `Failure("should not be None")`
+```
+
+## Exceptions
+
+- Raises `Failure` if `opt` is `None`
+*/
+let expect: (option<'a>, string) => 'a
+
 /**
 `getUnsafe(value)` returns `value`.
 

From 90483c888901bbc37274fb37732e91e8f9b6ae99 Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Sun, 19 Feb 2023 15:53:36 +0100
Subject: [PATCH 03/12] refactor(option): consistent variable naming in
 implementation

---
 src/Core__Option.mjs | 14 +++++++-------
 src/Core__Option.res | 34 +++++++++++++++++-----------------
 2 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/src/Core__Option.mjs b/src/Core__Option.mjs
index 4a036610..149726db 100644
--- a/src/Core__Option.mjs
+++ b/src/Core__Option.mjs
@@ -26,9 +26,9 @@ function forEach(opt, f) {
   
 }
 
-function getExn(x) {
-  if (x !== undefined) {
-    return Caml_option.valFromOption(x);
+function getExn(opt) {
+  if (opt !== undefined) {
+    return Caml_option.valFromOption(opt);
   }
   throw {
         RE_EXN_ID: "Not_found",
@@ -88,12 +88,12 @@ function orElse(opt, other) {
   }
 }
 
-function isSome(x) {
-  return x !== undefined;
+function isSome(opt) {
+  return opt !== undefined;
 }
 
-function isNone(x) {
-  return x === undefined;
+function isNone(value) {
+  return value === undefined;
 }
 
 function eq(a, b, f) {
diff --git a/src/Core__Option.res b/src/Core__Option.res
index 90d03a41..948e4bfd 100644
--- a/src/Core__Option.res
+++ b/src/Core__Option.res
@@ -30,23 +30,23 @@ let flat = opt =>
 
 let filterU = (opt, p) =>
   switch opt {
-  | Some(x) as some if p(. x) => some
+  | Some(value) as some if p(. value) => some
   | _ => None
   }
 
-let filter = (opt, p) => filterU(opt, (. x) => p(x))
+let filter = (opt, p) => filterU(opt, (. value) => p(value))
 
 let forEachU = (opt, f) =>
   switch opt {
-  | Some(x) => f(. x)
+  | Some(value) => f(. value)
   | None => ()
   }
 
-let forEach = (opt, f) => forEachU(opt, (. x) => f(x))
+let forEach = (opt, f) => forEachU(opt, (. value) => f(value))
 
-let getExn = x =>
-  switch x {
-  | Some(x) => x
+let getExn = opt =>
+  switch opt {
+  | Some(value) => value
   | None => raise(Not_found)
   }
 
@@ -60,31 +60,31 @@ external getUnsafe: option<'a> => 'a = "%identity"
 
 let mapWithDefaultU = (opt, default, f) =>
   switch opt {
-  | Some(x) => f(. x)
+  | Some(value) => f(. value)
   | None => default
   }
 
-let mapWithDefault = (opt, default, f) => mapWithDefaultU(opt, default, (. x) => f(x))
+let mapWithDefault = (opt, default, f) => mapWithDefaultU(opt, default, (. value) => f(value))
 
 let mapU = (opt, f) =>
   switch opt {
-  | Some(x) => Some(f(. x))
+  | Some(value) => Some(f(. value))
   | None => None
   }
 
-let map = (opt, f) => mapU(opt, (. x) => f(x))
+let map = (opt, f) => mapU(opt, (. value) => f(value))
 
 let flatMapU = (opt, f) =>
   switch opt {
-  | Some(x) => f(. x)
+  | Some(value) => f(. value)
   | None => None
   }
 
-let flatMap = (opt, f) => flatMapU(opt, (. x) => f(x))
+let flatMap = (opt, f) => flatMapU(opt, (. value) => f(value))
 
 let getWithDefault = (opt, default) =>
   switch opt {
-  | Some(x) => x
+  | Some(value) => value
   | None => default
   }
 
@@ -94,13 +94,13 @@ let orElse = (opt, other) =>
   | None => other
   }
 
-let isSome = x =>
-  switch x {
+let isSome = opt =>
+  switch opt {
   | Some(_) => true
   | None => false
   }
 
-let isNone = x => x == None
+let isNone = value => value == None
 
 let eqU = (a, b, f) =>
   switch a {

From f61e47e0296d11b73d40a2c6f005d0f35a1d2f5b Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Sun, 19 Feb 2023 16:00:53 +0100
Subject: [PATCH 04/12] docs(option/getExn): more specific description

---
 src/Core__Option.resi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index 1e5bf6e8..723ecb33 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -78,7 +78,7 @@ Option.forEach(None, x => Console.log(x)) // returns ()
 let forEach: (option<'a>, 'a => unit) => unit
 
 /**
-`getExn(opt)` returns `value` if `opt` is `Some(value)`, otherwise raises an exception.
+`getExn(opt)` returns `value` if `opt` is `Some(value)`, raises `Not_found` if `None`.
 
 ```rescript
 Option.getExn(Some(3)) // 3
@@ -87,7 +87,7 @@ Option.getExn(None) /* Raises an Error */
 
 ## Exceptions
 
-- Raises an error if `opt` is `None`
+- Raises `Not_found` if `opt` is `None`
 */
 let getExn: option<'a> => 'a
 

From 79c80868b70ea0c06f6ae9369d4c5afef51f5e31 Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Sun, 19 Feb 2023 16:01:59 +0100
Subject: [PATCH 05/12] docs(option/getUnsafe): more precise description of
 unsafe

---
 src/Core__Option.resi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index 723ecb33..ee47474d 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -115,9 +115,9 @@ Option.getUnsafe(Some(3)) == 3
 Option.getUnsafe(None) // Raises an error
 ```
 
-## Exceptions
+## Improtant
 
-- This is an unsafe operation, it assumes `value` is neither `None` nor `Some(None(...)))`
+This is an unsafe operation, it assumes `value` is neither `None`, `Some(None))`, `Some(Some(None))` etc.
 */
 external getUnsafe: option<'a> => 'a = "%identity"
 

From be9897ed5d2a0376820501b024de5d30edf69650 Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Sun, 19 Feb 2023 16:09:20 +0100
Subject: [PATCH 06/12] feat(option): add or as replacement for orElse,
 deprecate orElse

---
 src/Core__Option.mjs  |  5 ++++-
 src/Core__Option.res  |  5 +++--
 src/Core__Option.resi | 14 ++++++++++++++
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/Core__Option.mjs b/src/Core__Option.mjs
index 149726db..58088a4d 100644
--- a/src/Core__Option.mjs
+++ b/src/Core__Option.mjs
@@ -80,7 +80,7 @@ function getWithDefault(opt, $$default) {
   }
 }
 
-function orElse(opt, other) {
+function or(opt, other) {
   if (opt !== undefined) {
     return opt;
   } else {
@@ -124,6 +124,8 @@ function cmp(a, b, f) {
   }
 }
 
+var orElse = or;
+
 export {
   flat ,
   filter ,
@@ -134,6 +136,7 @@ export {
   map ,
   flatMap ,
   getWithDefault ,
+  or ,
   orElse ,
   isSome ,
   isNone ,
diff --git a/src/Core__Option.res b/src/Core__Option.res
index 948e4bfd..c1b9ffdc 100644
--- a/src/Core__Option.res
+++ b/src/Core__Option.res
@@ -88,9 +88,9 @@ let getWithDefault = (opt, default) =>
   | None => default
   }
 
-let orElse = (opt, other) =>
+let or = (opt, other) =>
   switch opt {
-  | Some(_) as some => some
+  | Some(_) => opt
   | None => other
   }
 
@@ -99,6 +99,7 @@ let isSome = opt =>
   | Some(_) => true
   | None => false
   }
+let orElse = or
 
 let isNone = value => value == None
 
diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index ee47474d..3c15aa0e 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -186,6 +186,19 @@ None->greet // "Greetings Anonymous"
 */
 let getWithDefault: (option<'a>, 'a) => 'a
 
+/**
+`or(opt1, opt2)` returns `opt2` if `opt1` is `None`, otherwise `opt1`.
+
+## Examples
+
+```rescript
+Option.or(Some(1812), Some(1066)) == Some(1812)
+Option.or(None, Some(1066) == Some(1066)
+Option.or(None, None) == None
+```
+*/
+let or: (option<'a>, option<'a>) => option<'a>
+
 /**
 `orElse(opt1, opt2)` returns `opt2` if `opt1` is `None`, otherwise `opt1`.
 
@@ -197,6 +210,7 @@ Option.orElse(None, Some(1066) == Some(1066)
 Option.orElse(None, None) == None
 ```
 */
+@deprecated
 let orElse: (option<'a>, option<'a>) => option<'a>
 
 /**

From de8a86ffb78e368ee69e387b6feb6766e8e03d97 Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Sun, 19 Feb 2023 16:10:11 +0100
Subject: [PATCH 07/12] refactor(option): simplify implementation of isSome

---
 src/Core__Option.mjs | 4 ++--
 src/Core__Option.res | 9 +++------
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/src/Core__Option.mjs b/src/Core__Option.mjs
index 58088a4d..0b922916 100644
--- a/src/Core__Option.mjs
+++ b/src/Core__Option.mjs
@@ -92,8 +92,8 @@ function isSome(opt) {
   return opt !== undefined;
 }
 
-function isNone(value) {
-  return value === undefined;
+function isNone(opt) {
+  return opt === undefined;
 }
 
 function eq(a, b, f) {
diff --git a/src/Core__Option.res b/src/Core__Option.res
index c1b9ffdc..9d264bc6 100644
--- a/src/Core__Option.res
+++ b/src/Core__Option.res
@@ -94,14 +94,11 @@ let or = (opt, other) =>
   | None => other
   }
 
-let isSome = opt =>
-  switch opt {
-  | Some(_) => true
-  | None => false
-  }
 let orElse = or
 
-let isNone = value => value == None
+let isSome = opt => opt !== None
+
+let isNone = opt => opt == None
 
 let eqU = (a, b, f) =>
   switch a {

From 5c0644055b9783f1f48ada4dc8c4c8d0985d266d Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Thu, 2 Mar 2023 10:53:35 +0100
Subject: [PATCH 08/12] docs: update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9e8490e2..9e3d3801 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,7 @@
 - Add `panic`/`Error.panic`. https://github.com/rescript-association/rescript-core/pull/72
 - The globally available `null` value now originates from `Nullable` and not `Null`, just like the globally available `undefined` value does. https://github.com/rescript-association/rescript-core/pull/88
 - Add `Int.range` and `Int.rangeWithOptions`, https://github.com/rescript-association/rescript-core/pull/52
+- Add `flat`, `expect`, and `or` to `Option`, deprecate `orElse`. https://github.com/rescript-association/rescript-core/pull/57
 
 ### Documentation
 

From a056cd0e870fb23dd7d66c97668cf92196deefd5 Mon Sep 17 00:00:00 2001
From: Glenn Slotte <glenn@slotte.net>
Date: Sun, 19 Feb 2023 19:12:01 +0100
Subject: [PATCH 09/12] docs(option): fix embarassing typos

Co-authored-by: Christoph Knittel <christoph@knittel.cc>
---
 src/Core__Option.resi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index 3c15aa0e..84c7cf21 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -40,7 +40,7 @@ let someString: option<string> = Some("hello")
 */
 
 /**
-`flat(value)` flattens a nested `option` value to a single level..
+`flat(value)` flattens a nested `option` value to a single level.
 
 ## Examples
 
@@ -115,7 +115,7 @@ Option.getUnsafe(Some(3)) == 3
 Option.getUnsafe(None) // Raises an error
 ```
 
-## Improtant
+## Important
 
 This is an unsafe operation, it assumes `value` is neither `None`, `Some(None))`, `Some(Some(None))` etc.
 */

From 29b3d5d65533a3532a65a6b188d53871ef50328c Mon Sep 17 00:00:00 2001
From: Glenn Slotte <glenn@slotte.net>
Date: Mon, 20 Feb 2023 20:02:45 +0100
Subject: [PATCH 10/12] docs(option/orElse): add deprecation message

Co-authored-by: Pedro Castro <aspeddro@gmail.com>
---
 src/Core__Option.resi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index 84c7cf21..468a77c5 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -210,7 +210,7 @@ Option.orElse(None, Some(1066) == Some(1066)
 Option.orElse(None, None) == None
 ```
 */
-@deprecated
+@deprecated("Use `or` instead")
 let orElse: (option<'a>, option<'a>) => option<'a>
 
 /**

From 8b198d50b825352b86d0772cc5e11267775b069c Mon Sep 17 00:00:00 2001
From: Glenn Slotte <glenn@slotte.net>
Date: Mon, 20 Feb 2023 20:03:21 +0100
Subject: [PATCH 11/12] docs(option/flat): flat is not float

Co-authored-by: Pedro Castro <aspeddro@gmail.com>
---
 src/Core__Option.resi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index 468a77c5..5a9a009b 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -45,7 +45,7 @@ let someString: option<string> = Some("hello")
 ## Examples
 
 ```rescript
-Option.float(Some(Some(10))) // Some(10)
+Option.flat(Some(Some(10))) // Some(10)
 Option.flat(Some(None)) // None
 ```
 */

From 9280051282163546cbea1130cbd6b0c37083666c Mon Sep 17 00:00:00 2001
From: glennsl <glenn@slotte.net>
Date: Thu, 2 Mar 2023 11:02:18 +0100
Subject: [PATCH 12/12] feat(error/expect): use panic instead of raising
 Failure

---
 src/Core__Option.mjs  | 8 +++-----
 src/Core__Option.res  | 2 +-
 src/Core__Option.resi | 2 +-
 3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/Core__Option.mjs b/src/Core__Option.mjs
index 0b922916..d0679d4c 100644
--- a/src/Core__Option.mjs
+++ b/src/Core__Option.mjs
@@ -2,6 +2,7 @@
 
 import * as Curry from "rescript/lib/es6/curry.js";
 import * as Caml_option from "rescript/lib/es6/caml_option.js";
+import * as Core__Error from "./Core__Error.mjs";
 
 function flat(opt) {
   if (opt !== undefined) {
@@ -39,12 +40,9 @@ function getExn(opt) {
 function expect(opt, message) {
   if (opt !== undefined) {
     return Caml_option.valFromOption(opt);
+  } else {
+    return Core__Error.panic(message);
   }
-  throw {
-        RE_EXN_ID: "Failure",
-        _1: message,
-        Error: new Error()
-      };
 }
 
 function mapWithDefault(opt, $$default, f) {
diff --git a/src/Core__Option.res b/src/Core__Option.res
index 9d264bc6..726a074f 100644
--- a/src/Core__Option.res
+++ b/src/Core__Option.res
@@ -53,7 +53,7 @@ let getExn = opt =>
 let expect = (opt, message) =>
   switch opt {
   | Some(value) => value
-  | None => raise(Failure(message))
+  | None => Core__Error.panic(message)
   }
 
 external getUnsafe: option<'a> => 'a = "%identity"
diff --git a/src/Core__Option.resi b/src/Core__Option.resi
index 5a9a009b..2c1f2025 100644
--- a/src/Core__Option.resi
+++ b/src/Core__Option.resi
@@ -101,7 +101,7 @@ Option.expect(None, "should not be None") // Raises `Failure("should not be None
 
 ## Exceptions
 
-- Raises `Failure` if `opt` is `None`
+- Panics if `opt` is `None`
 */
 let expect: (option<'a>, string) => 'a