chore: add Ord.tuple

Author: mikearnaldi

.changeset/heavy-steaks-hope.md

@@ -0,0 +1,5 @@
+---
+"@tsplus/stdlib": patch
+---
+
+Add Ord.tuple

packages/stdlib/_src/prelude/Ord.ts

@@ -5,4 +5,5 @@ export * from "@tsplus/stdlib/prelude/Ord/definition"
 export * from "@tsplus/stdlib/prelude/Ord/getAssociative"
 export * from "@tsplus/stdlib/prelude/Ord/getAssociativeIdentity"
 export * from "@tsplus/stdlib/prelude/Ord/operations"
+export * from "@tsplus/stdlib/prelude/Ord/tuple"
 // codegen:end

packages/stdlib/_src/prelude/Ord/tuple.ts

@@ -0,0 +1,27 @@
+export type NonEmptyArrayOrd = Array<Ord<any>> & { readonly 0: Ord<any> }
+
+export type TupleOrd<T extends NonEmptyArrayOrd> = {
+  [K in keyof T]: [T[K]] extends [Ord<infer A>] ? A : never
+}
+
+/**
+ * Derives an Ord instance for a tuple
+ *
+ * @tsplus static Ord/Ops tuple
+ */
+export function tuple<T extends NonEmptyArrayOrd>(
+  ...ords: T & {
+    readonly 0: Ord<any>
+  }
+): Ord<ForcedTuple<TupleOrd<T>>> {
+  return Ord((first, second) => {
+    let i = 0
+    for (; i < ords.length - 1; i++) {
+      const r = ords[i]!.compare(first[i], second[i])
+      if (r !== 0) {
+        return r
+      }
+    }
+    return ords[i]!.compare(first[i], second[i])
+  })
+}