From 38fc122b84fce3a0e6299069524e80a73818d928 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 10 Apr 2023 13:19:19 +0100
Subject: Constraint operator* collection helper to IterableCollections

---
 lib/collections.hpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'lib/collections.hpp')

diff --git a/lib/collections.hpp b/lib/collections.hpp
index 59cec6f..4df622e 100644
--- a/lib/collections.hpp
+++ b/lib/collections.hpp
@@ -65,10 +65,11 @@ operator*=(IterableCollection auto & in, auto && f)
 }
 
 template<template<typename...> typename C, typename... T>
+	requires IterableCollection<C<T...>>
 [[nodiscard]] constexpr auto
 operator*(const C<T...> & in, auto && f)
 {
-	C<decltype(f(in[0]))> out;
+	C<decltype(f(*in.begin()))> out;
 
 	std::transform(in.begin(), in.end(), std::inserter(out, out.end()), f);
 	return out;
-- 
cgit v1.2.3


From a5a0ad3634c512afb1686a2ec8940843e7f0eb63 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 10 Apr 2023 13:20:49 +0100
Subject: operator* collection helper reserves target space when possible

---
 lib/collections.hpp | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'lib/collections.hpp')

diff --git a/lib/collections.hpp b/lib/collections.hpp
index 4df622e..b51d18e 100644
--- a/lib/collections.hpp
+++ b/lib/collections.hpp
@@ -70,6 +70,9 @@ template<template<typename...> typename C, typename... T>
 operator*(const C<T...> & in, auto && f)
 {
 	C<decltype(f(*in.begin()))> out;
+	if constexpr (requires { out.reserve(in.size()); }) {
+		out.reserve(in.size());
+	}
 
 	std::transform(in.begin(), in.end(), std::inserter(out, out.end()), f);
 	return out;
-- 
cgit v1.2.3


From e7d946aadebfdf49cc96e6a518c1af1ef7f5c71c Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 10 Apr 2023 14:34:56 +0100
Subject: Add operator* helper specialised for std::span

---
 lib/collections.hpp | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'lib/collections.hpp')

diff --git a/lib/collections.hpp b/lib/collections.hpp
index b51d18e..8f5a43d 100644
--- a/lib/collections.hpp
+++ b/lib/collections.hpp
@@ -78,6 +78,27 @@ operator*(const C<T...> & in, auto && f)
 	return out;
 }
 
+template<typename T, std::size_t N>
+[[nodiscard]] constexpr auto
+operator*(const std::span<T, N> in, auto && f)
+{
+	std::array<decltype(f(std::declval<T>())), N> out;
+
+	std::transform(in.begin(), in.end(), out.begin(), f);
+	return out;
+}
+
+template<typename T>
+[[nodiscard]] constexpr auto
+operator*(const std::span<T, std::dynamic_extent> in, auto && f)
+{
+	std::vector<decltype(f(std::declval<T>()))> out;
+
+	out.reserve(in.size());
+	std::transform(in.begin(), in.end(), std::inserter(out, out.end()), f);
+	return out;
+}
+
 template<typename... T>
 constexpr auto &
 operator+=(std::vector<T...> & in, std::vector<T...> && src)
-- 
cgit v1.2.3