add comparison fn for Error in Result.equal and compare (#7933)

* add Error comparison fn in Result.equal and compare

* rename fOk, fError to eqOk, eqError, cmpOk, cmpError

Author: tsnobip

CHANGELOG.md

@@ -15,6 +15,7 @@
 #### :boom: Breaking Change
 
 - Removed "rescript legacy" subcommand in favor of separate "rescript-legacy" binary. https://github.com/rescript-lang/rescript/pull/7928
+- Add comparison fn for Error in Result.equal and compare. https://github.com/rescript-lang/rescript/pull/7933
 
 #### :eyeglasses: Spec Compliance
 

packages/@rescript/runtime/Stdlib_Result.res

@@ -77,20 +77,20 @@ let isError = x =>
   | Error(_) => true
   }
 
-let equal = (a, b, f) =>
+let equal = (a, b, eqOk, eqError) =>
   switch (a, b) {
-  | (Ok(a), Ok(b)) => f(a, b)
+  | (Ok(a), Ok(b)) => eqOk(a, b)
   | (Error(_), Ok(_))
   | (Ok(_), Error(_)) => false
-  | (Error(_), Error(_)) => true
+  | (Error(a), Error(b)) => eqError(a, b)
   }
 
-let compare = (a, b, f) =>
+let compare = (a, b, cmpOk, cmpError) =>
   switch (a, b) {
-  | (Ok(a), Ok(b)) => f(a, b)
+  | (Ok(a), Ok(b)) => cmpOk(a, b)
   | (Error(_), Ok(_)) => Stdlib_Ordering.less
   | (Ok(_), Error(_)) => Stdlib_Ordering.greater
-  | (Error(_), Error(_)) => Stdlib_Ordering.equal
+  | (Error(a), Error(b)) => cmpError(a, b)
   }
 
 let forEach = (r, f) =>

packages/@rescript/runtime/Stdlib_Result.resi

@@ -172,11 +172,11 @@ let isOk: result<'a, 'b> => bool
 let isError: result<'a, 'b> => bool
 
 /**
-`equal(res1, res2, f)`: Determine if two `Result` variables are equal with
-respect to an equality function. If `res1` and `res2` are of the form `Ok(n)`
-and `Ok(m)`, return the result of `f(n, m)`. If one of `res1` and `res2` are of
+`equal(res1, res2, eqOk, eqError)`: Determine if two `Result` variables are equal with
+respect to equality functions. If `res1` and `res2` are of the form `Ok(n)`
+and `Ok(m)`, return the result of `eqOk(n, m)`. If one of `res1` and `res2` are of
 the form `Error(e)`, return false If both `res1` and `res2` are of the form
-`Error(e)`, return true
+`Error(e)`, return the result of `eqError(e1, e2)`.
 
 ## Examples
 
@@ -191,28 +191,28 @@ let bad2 = Error("really invalid")
 
 let mod10equal = (a, b) => mod(a, 10) === mod(b, 10)
 
-Result.equal(good1, good2, mod10equal) == true
+Result.equal(good1, good2, mod10equal, String.equal) == true
 
-Result.equal(good1, bad1, mod10equal) == false
+Result.equal(good1, bad1, mod10equal, String.equal) == false
 
-Result.equal(bad2, good2, mod10equal) == false
+Result.equal(bad2, good2, mod10equal, String.equal) == false
 
-Result.equal(bad1, bad2, mod10equal) == true
+Result.equal(bad1, bad2, mod10equal, String.equal) == false
 ```
 */
-let equal: (result<'a, 'c>, result<'b, 'd>, ('a, 'b) => bool) => bool
+let equal: (result<'a, 'c>, result<'b, 'd>, ('a, 'b) => bool, ('c, 'd) => bool) => bool
 
 /**
-`compare(res1, res2, f)`: Compare two `Result` variables with respect to a
+`compare(res1, res2, cmpOk, cmpError)`: Compare two `Result` variables with respect to a
 comparison function. The comparison function returns -1. if the first variable
 is "less than" the second, 0. if the two variables are equal, and 1. if the first
 is "greater than" the second.
 
 If `res1` and `res2` are of the form `Ok(n)` and `Ok(m)`, return the result of
-`f(n, m)`. If `res1` is of the form `Error(e)` and `res2` of the form `Ok(n)`,
+`cmpOk(n, m)`. If `res1` is of the form `Error(e)` and `res2` of the form `Ok(n)`,
 return -1. (nothing is less than something) If `res1` is of the form `Ok(n)` and
-`res2` of the form `Error(e)`, return 1. (something is greater than nothing) If
-both `res1` and `res2` are of the form `Error(e)`, return 0. (equal)
+`res2` is of the form `Error(e)`, return 1. (something is greater than nothing) If
+both `res1` and `res2` are of the form `Error(e)`, return cmpError(e1, e2).
 
 ## Examples
 
@@ -227,18 +227,23 @@ let bad2 = Error("really invalid")
 
 let mod10cmp = (a, b) => Int.compare(mod(a, 10), mod(b, 10))
 
-Result.compare(Ok(39), Ok(57), mod10cmp) == 1.
+Result.compare(Ok(39), Ok(57), mod10cmp, String.compare) == 1.
 
-Result.compare(Ok(57), Ok(39), mod10cmp) == -1.
+Result.compare(Ok(57), Ok(39), mod10cmp, String.compare) == -1.
 
-Result.compare(Ok(39), Error("y"), mod10cmp) == 1.
+Result.compare(Ok(39), Error("y"), mod10cmp, String.compare) == 1.
 
-Result.compare(Error("x"), Ok(57), mod10cmp) == -1.
+Result.compare(Error("x"), Ok(57), mod10cmp, String.compare) == -1.
 
-Result.compare(Error("x"), Error("y"), mod10cmp) == 0.
+Result.compare(Error("x"), Error("y"), mod10cmp, String.compare) == -1.
 ```
 */
-let compare: (result<'a, 'c>, result<'b, 'd>, ('a, 'b) => Stdlib_Ordering.t) => Stdlib_Ordering.t
+let compare: (
+  result<'a, 'c>,
+  result<'b, 'd>,
+  ('a, 'b) => Stdlib_Ordering.t,
+  ('c, 'd) => Stdlib_Ordering.t,
+) => Stdlib_Ordering.t
 
 /**
 `forEach(res, f)` runs the provided function `f` on the `Ok` value. If `res` is `Error`, nothing happens.

packages/@rescript/runtime/lib/es6/Stdlib_Result.js

@@ -53,29 +53,31 @@ function isError(x) {
   return x.TAG !== "Ok";
 }
 
-function equal(a, b, f) {
+function equal(a, b, eqOk, eqError) {
   if (a.TAG === "Ok") {
     if (b.TAG === "Ok") {
-      return f(a._0, b._0);
+      return eqOk(a._0, b._0);
     } else {
       return false;
     }
+  } else if (b.TAG === "Ok") {
+    return false;
   } else {
-    return b.TAG !== "Ok";
+    return eqError(a._0, b._0);
   }
 }
 
-function compare(a, b, f) {
+function compare(a, b, cmpOk, cmpError) {
   if (a.TAG === "Ok") {
     if (b.TAG === "Ok") {
-      return f(a._0, b._0);
+      return cmpOk(a._0, b._0);
     } else {
       return 1;
     }
   } else if (b.TAG === "Ok") {
     return -1;
   } else {
-    return 0;
+    return cmpError(a._0, b._0);
   }
 }
 

packages/@rescript/runtime/lib/js/Stdlib_Result.js

@@ -53,29 +53,31 @@ function isError(x) {
   return x.TAG !== "Ok";
 }
 
-function equal(a, b, f) {
+function equal(a, b, eqOk, eqError) {
   if (a.TAG === "Ok") {
     if (b.TAG === "Ok") {
-      return f(a._0, b._0);
+      return eqOk(a._0, b._0);
     } else {
       return false;
     }
+  } else if (b.TAG === "Ok") {
+    return false;
   } else {
-    return b.TAG !== "Ok";
+    return eqError(a._0, b._0);
   }
 }
 
-function compare(a, b, f) {
+function compare(a, b, cmpOk, cmpError) {
   if (a.TAG === "Ok") {
     if (b.TAG === "Ok") {
-      return f(a._0, b._0);
+      return cmpOk(a._0, b._0);
     } else {
       return 1;
     }
   } else if (b.TAG === "Ok") {
     return -1;
   } else {
-    return 0;
+    return cmpError(a._0, b._0);
   }
 }