From c88f404555e566d255b653e6de2a6b51bacc6dd4 Mon Sep 17 00:00:00 2001
From: Andrew Morris <voltrevo@gmail.com>
Date: Thu, 1 Jun 2023 15:20:57 +1000
Subject: [PATCH] Start working on range

---
 inputs/passing/helpers/range.ts       | 56 +++++++++++++++++++++++++++
 inputs/passing/iteration/testRange.ts | 12 ++++++
 website/.eslintrc.cjs                 | 10 ++++-
 3 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 inputs/passing/helpers/range.ts
 create mode 100644 inputs/passing/iteration/testRange.ts

diff --git a/inputs/passing/helpers/range.ts b/inputs/passing/helpers/range.ts
new file mode 100644
index 0000000..339d4c2
--- /dev/null
+++ b/inputs/passing/helpers/range.ts
@@ -0,0 +1,56 @@
+export default function range<T = never>(iter?: Iterable<T> | Iterator<T>) {
+  return new Range<T>(iter);
+}
+
+class Range<T = never> implements Iterable<T> {
+  iterable: Iterable<T>;
+
+  constructor(iter?: Iterable<T> | Iterator<T>) {
+    if (iter === undefined) {
+      this.iterable = [];
+    } else if (isIterator(iter)) {
+      this.iterable = {
+        [Symbol.iterator]: () => iter,
+      };
+    } else {
+      this.iterable = iter;
+    }
+  }
+
+  [Symbol.iterator]() {
+    return this.iterable[Symbol.iterator]();
+  }
+
+  limit(n: number) {
+    const iterable = this.iterable;
+
+    function* res() {
+      let i = 0;
+
+      for (const x of iterable) {
+        if (i >= n) {
+          break;
+        }
+
+        yield x;
+        i++;
+      }
+    }
+
+    return range(res());
+  }
+
+  count() {
+    let i = 0;
+
+    for (const _x of this.iterable) {
+      i++;
+    }
+
+    return i;
+  }
+}
+
+function isIterator<T>(iter: Iterable<T> | Iterator<T>): iter is Iterator<T> {
+  return (iter as unknown as Record<string, unknown>).next !== undefined;
+}
diff --git a/inputs/passing/iteration/testRange.ts b/inputs/passing/iteration/testRange.ts
new file mode 100644
index 0000000..231eb7d
--- /dev/null
+++ b/inputs/passing/iteration/testRange.ts
@@ -0,0 +1,12 @@
+// test_output! [0,2,[2,3,5,7,11]]
+
+import range from "../helpers/range.ts";
+import { primes } from "../projEuler/helpers/primes.ts";
+
+export default function main() {
+  return [
+    range().count(),
+    range([1, 2, 3]).limit(2).count(),
+    [...range(primes()).limit(5)],
+  ];
+}
diff --git a/website/.eslintrc.cjs b/website/.eslintrc.cjs
index 0175f7c..d2a11a1 100644
--- a/website/.eslintrc.cjs
+++ b/website/.eslintrc.cjs
@@ -29,7 +29,15 @@ module.exports = {
     "comma-dangle": ["error", "always-multiline"],
     "react/react-in-jsx-scope": "off",
     "quote-props": ["error", "consistent-as-needed"],
-    "@typescript-eslint/no-unused-vars": ["error", { argsIgnorePattern: "^_" }],
+    "@typescript-eslint/no-unused-vars": [
+      "error",
+      {
+        argsIgnorePattern: "^_",
+        varsIgnorePattern: "^_",
+        caughtErrorsIgnorePattern: "^_",
+        destructuredArrayIgnorePattern: "^_",
+      },
+    ],
     "prettier/prettier": "error",
     "no-constant-condition": "off",
     "no-empty": ["error", { allowEmptyCatch: true }],