Do not support array + integer or integer + array. Require that the argument is a pointer instead.

Author: davidstone

source/bounded/CMakeLists.txt

@@ -117,6 +117,8 @@ set_source_files_properties(arithmetic/operators_builtin.cpp
 	PROPERTIES COMPILE_FLAGS "-Wno-implicit-int-conversion -Wno-shorten-64-to-32"
 )
 
+add_subdirectory(arithmetic/test)
+
 add_executable(bounded_test)
 
 target_sources(bounded_test PRIVATE

source/bounded/arithmetic/pointer.cpp

@@ -5,77 +5,19 @@
 
 export module bounded.arithmetic.pointer;
 
-import bounded.arithmetic.plus;
 import bounded.bounded_integer;
-import bounded.comparison;
-import bounded.integer;
-
-import numeric_traits;
-import std_module;
 
 namespace bounded {
 
-namespace {
-
-// This is faster to compile than `std::is_pointer_v`
-template<typename>
-constexpr auto is_pointer = false;
-
-template<typename T>
-constexpr auto is_pointer<T *> = true;
-
-} // namespace
-
-export template<typename T, bounded_integer Integer> requires(
-	(is_pointer<T> or (std::is_array_v<T> and numeric_traits::max_value<Integer> <= constant<std::extent_v<T>>))
-)
-constexpr auto operator+(T const & array, Integer const number) {
-	return array + number.value();
+export template<typename T>
+constexpr auto operator+(T * const & ptr, bounded_integer auto const number) -> T * {
+	return ptr + number.value();
 }
 
 
-export template<bounded_integer Integer, typename T> requires(
-	(is_pointer<T> or (std::is_array_v<T> and numeric_traits::max_value<Integer> <= constant<std::extent_v<T>>))
-)
-constexpr auto operator+(Integer const number, T const & array) {
-	return number.value() + array;
+export template<typename T>
+constexpr auto operator+(bounded_integer auto const number, T * const & ptr) -> T * {
+	return number.value() + ptr;
 }
 
-// Not possible to overload operator[]. See
-// https://groups.google.com/a/isocpp.org/forum/#!topic/std-proposals/CmBERU_sr8Y
-
-} // namespace bounded
-
-namespace {
-
-using array_type = int[5];
-constexpr array_type array{ 0, 1, 2, 3, 4 };
-
-static_assert(
-	*(std::begin(array) + bounded::constant<0>) == 0,
-	"Incorrect pointer arithmetic with bounded::integer."
-);
-static_assert(
-	*(array + bounded::constant<0>) == 0,
-	"Incorrect array arithmetic with bounded::integer."
-);
-static_assert(
-	array + bounded::constant<5> == std::end(array),
-	"Incorrect array arithmetic with bounded::integer."
-);
-
-
-#if 0
-// TODO: Test that this does not compile, improve error message
-array + bounded::constant<6>
-#endif
-
-// Oops, not possible to overload array index operator
-#if 0
-static_assert(
-	array[bounded::constant<0>] == 0,
-	"Incorrect array indexing with bounded::integer."
-);
-#endif
-
-} // namespace
+} // namespace bounded

source/bounded/arithmetic/test/CMakeLists.txt

@@ -0,0 +1,20 @@
+# Copyright David Stone 2024.
+# Distributed under the Boost Software License, Version 1.0.
+# (See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt)
+
+add_library(bounded_arithmetic_test)
+
+target_sources(bounded_arithmetic_test PRIVATE
+	FILE_SET CXX_MODULES
+	BASE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}"
+	FILES
+		pointer.cpp
+)
+
+target_link_libraries(bounded_arithmetic_test PUBLIC
+	bounded
+	strict_defaults
+)
+
+add_test(bounded_arithmetic_test bounded_arithmetic_test)

source/bounded/arithmetic/test/pointer.cpp

@@ -0,0 +1,23 @@
+// Copyright David Stone 2024.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+export module bounded.arithmetic.test.pointer;
+
+import bounded.arithmetic.pointer;
+
+import bounded.bounded_integer;
+import bounded.literal;
+
+import std_module;
+
+namespace {
+using namespace bounded::literal;
+
+constexpr int array[5] = {};
+
+static_assert(std::begin(array) + 0_bi == std::begin(array));
+static_assert(std::begin(array) + 5_bi == std::end(array));
+
+} // namespace