Use float for ordering, add Ordering module

CHANGELOG.md

@@ -22,6 +22,8 @@
   - `fillAllInPlace` -> `fillAll`, `fillInPlaceToEnd` -> `fillToEnd`, `fillInPlace` -> `fill`
 - And `List`:
   - `shuffle` -> `toShuffled`
+- Use `float` instead of `int` for ordering to avoid premature overflow. https://github.com/rescript-association/rescript-core/pull/149
+- Add `Ordering` module. https://github.com/rescript-association/rescript-core/pull/149
 
 **Note 1**: These changes should all produce the correct type errors. Though `TypedArray`'s `reverse` and `sort` previously mutated _and_ returned the mutated array itself, whereas now they'd be copies. Please be careful refactoring these 2.
 

src/Core__Array.mjs

@@ -3,6 +3,7 @@
 import * as Curry from "rescript/lib/es6/curry.js";
 import * as Js_math from "rescript/lib/es6/js_math.js";
 import * as Caml_option from "rescript/lib/es6/caml_option.js";
+import * as Core__Ordering from "./Core__Ordering.mjs";
 
 function make(length, x) {
   if (length <= 0) {
@@ -47,10 +48,10 @@ function equal(a, b, eq) {
 function compare(a, b, cmp) {
   var lenA = a.length;
   var lenB = b.length;
-  if (lenA > lenB) {
-    return 1;
-  } else if (lenA < lenB) {
+  if (lenA < lenB) {
     return -1;
+  } else if (lenA > lenB) {
+    return 1;
   } else {
     var _i = 0;
     while(true) {
@@ -59,7 +60,7 @@ function compare(a, b, cmp) {
         return 0;
       }
       var c = Curry._2(cmp, a[i], b[i]);
-      if (c !== 0) {
+      if (!Core__Ordering.isEqual(c)) {
         return c;
       }
       _i = i + 1 | 0;

src/Core__Array.res

@@ -57,10 +57,10 @@ let equal = (a, b, eq) => {
 
 let rec compareFromIndex = (a, b, i, cmp, len) =>
   if i === len {
-    0
+    Core__Ordering.equal
   } else {
     let c = cmp(a->getUnsafe(i), b->getUnsafe(i))
-    if c === 0 {
+    if c->Core__Ordering.isEqual {
       compareFromIndex(a, b, i + 1, cmp, len)
     } else {
       c
@@ -70,13 +70,11 @@ let rec compareFromIndex = (a, b, i, cmp, len) =>
 let compare = (a, b, cmp) => {
   let lenA = a->length
   let lenB = b->length
-  if lenA > lenB {
-    1
-  } else if lenA < lenB {
-    -1
-  } else {
-    compareFromIndex(a, b, 0, cmp, lenA)
-  }
+  lenA < lenB
+    ? Core__Ordering.less
+    : lenA > lenB
+    ? Core__Ordering.greater
+    : compareFromIndex(a, b, 0, cmp, lenA)
 }
 
 @send external copyAllWithin: (array<'a>, ~target: int) => array<'a> = "copyWithin"
@@ -139,8 +137,8 @@ let lastIndexOfOpt = (arr, item) =>
 @send external sliceToEnd: (array<'a>, ~start: int) => array<'a> = "slice"
 @send external copy: array<'a> => array<'a> = "slice"
 
-@send external sort: (array<'a>, ('a, 'a) => int) => unit = "sort"
-@send external toSorted: (array<'a>, ('a, 'a) => int) => array<'a> = "toSorted"
+@send external sort: (array<'a>, ('a, 'a) => Core__Ordering.t) => unit = "sort"
+@send external toSorted: (array<'a>, ('a, 'a) => Core__Ordering.t) => array<'a> = "toSorted"
 
 @send external toString: array<'a> => string = "toString"
 @send external toLocaleString: array<'a> => string = "toLocaleString"

src/Core__Array.resi

@@ -29,7 +29,7 @@ let fromInitializer: (~length: int, int => 'a) => array<'a>
 
 let equal: (array<'a>, array<'a>, ('a, 'a) => bool) => bool
 
-let compare: (array<'a>, array<'a>, ('a, 'a) => int) => int
+let compare: (array<'a>, array<'a>, ('a, 'a) => Core__Ordering.t) => Core__Ordering.t
 
 @val external isArray: 'a => bool = "Array.isArray"
 
@@ -212,14 +212,14 @@ See [`Array.toSorted`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/R
 ## Examples
 ```rescript
 let someArray = [3, 2, 1]
-let sorted = someArray->Array.toSorted((a, b) => a - b)
+let sorted = someArray->Array.toSorted(Int.compare)
 
 Console.log(sorted) // [1, 2, 3]
 Console.log(someArray) // [3, 2, 1]. Original unchanged
 ```
 */
 @send
-external toSorted: (array<'a>, ('a, 'a) => int) => array<'a> = "toSorted"
+external toSorted: (array<'a>, ('a, 'a) => Core__Ordering.t) => array<'a> = "toSorted"
 
 /**
 `sort(array, comparator)` sorts `array` in-place using the `comparator` function.
@@ -231,13 +231,13 @@ See [`Array.sort`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refer
 ## Examples
 ```rescript
 let someArray = [3, 2, 1]
-someArray->Array.sort((a, b) => a - b)
+someArray->Array.sort((a, b) => float(a - b))
 
 Console.log(someArray) // [1, 2, 3]
 ```
 */
 @send
-external sort: (array<'a>, ('a, 'a) => int) => unit = "sort"
+external sort: (array<'a>, ('a, 'a) => Core__Ordering.t) => unit = "sort"
 
 @variadic @send
 external splice: (array<'a>, ~start: int, ~remove: int, ~insert: array<'a>) => unit = "splice"