From b2e36f4e0f403aa1af43f32201e73e641db5ddb2 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Tue, 29 Oct 2024 14:02:10 +1000
Subject: [PATCH] ranges: add izip helper

---
 cruft/util/CMakeLists.txt  |  1 +
 cruft/util/ranges/izip.hpp | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 cruft/util/ranges/izip.hpp

diff --git a/cruft/util/CMakeLists.txt b/cruft/util/CMakeLists.txt
index e799a912..815a920c 100644
--- a/cruft/util/CMakeLists.txt
+++ b/cruft/util/CMakeLists.txt
@@ -546,6 +546,7 @@ list (
     range.hpp
     ranges/chunk.hpp
     ranges/enumerate.hpp
+    ranges/izip.hpp
     rational.cpp
     rational.hpp
     region.cpp
diff --git a/cruft/util/ranges/izip.hpp b/cruft/util/ranges/izip.hpp
new file mode 100644
index 00000000..d2a15cf4
--- /dev/null
+++ b/cruft/util/ranges/izip.hpp
@@ -0,0 +1,18 @@
+#pragma once
+
+#include <ranges>
+
+
+namespace cruft::ranges {
+    /// A convenience function that combines enumerate and zip, such that a preceding index element is returned in
+    // the result tuple.
+    template <::std::ranges::viewable_range... Rs>
+    constexpr ::std::ranges::view auto
+    izip (Rs &&...rs)
+    {
+        return ::std::views::zip (
+            ::std::views::iota (0),
+            ::std::forward<Rs> (rs)...
+        );
+    }
+}