Add mutable_argv, closes #592

See discussion in #592 comment thread

Author: hsutter

include/cpp2util.h

@@ -205,6 +205,7 @@
     #include <string>
     #include <string_view>
     #include <vector>
+    #include <span>
     #include <iostream>
     #include <variant>
     #include <any>
@@ -1490,16 +1491,17 @@ inline auto to_string(std::tuple<Ts...> const& t) -> std::string
 //
 struct args_t : std::vector<std::string_view>
 {
-    args_t(int c, char const* const* v) : vector{static_cast<size_t>(c)}, argc{c}, argv{v} {}
+    args_t(int c, char** v) : vector{static_cast<size_t>(c)}, argc{c}, argv{v}, mutable_argv{v} {}
 
-    int                argc = 0;
-    char const* const* argv = nullptr;
+    int                argc         = 0;
+    char const* const* argv         = nullptr;
+    char**             mutable_argv = nullptr;
 };
 
-inline auto make_args(int argc, char const* const* argv) -> args_t
+inline auto make_args(int argc, char** argv) -> args_t
 {
     auto ret = args_t{argc, argv};
-    std::copy(argv, argv + argc, ret.data());
+    std::ranges::copy( std::span(argv, argc), ret.data() );
     return ret;
 }
 

regression-tests/pure2-main-args.cpp2

@@ -1,2 +1,6 @@
 main: (args) =
-    std::cout << "args.argc is (args.argc)$, and args.argv[0] is (args.argv[0])$\n";
+    std::cout
+        << "args.argc            is (args.argc)$\n"
+        << "args.argv[0]         is (args.argv[0])$\n"
+        << "args.mutable_argv[0] is (args.mutable_argv[0])$\n"
+        ;

regression-tests/test-results/clang-12/pure2-main-args.cpp.execution

@@ -1 +1,3 @@
-args.argc is 1, and args.argv[0] is ./test.exe
+args.argc            is 1
+args.argv[0]         is ./test.exe
+args.mutable_argv[0] is ./test.exe

regression-tests/test-results/gcc-13/pure2-main-args.cpp.execution

@@ -1 +1,3 @@
-args.argc is 1, and args.argv[0] is ./test.exe
+args.argc            is 1
+args.argv[0]         is ./test.exe
+args.mutable_argv[0] is ./test.exe

regression-tests/test-results/mixed-fixed-type-aliases.cpp

@@ -21,7 +21,7 @@ auto test(auto const& x) -> void;
 
 
 #line 15 "mixed-fixed-type-aliases.cpp2"
-[[nodiscard]] auto main(int const argc_, char const* const* const argv_) -> int;
+[[nodiscard]] auto main(int const argc_, char** argv_) -> int;
 
 
 //=== Cpp2 function definitions =================================================
@@ -35,7 +35,7 @@ auto test(auto const& x) -> void{
         << "\n";
 }
 
-[[nodiscard]] auto main(int const argc_, char const* const* const argv_) -> int{
+[[nodiscard]] auto main(int const argc_, char** argv_) -> int{
     auto args = cpp2::make_args(argc_, argv_); 
 #line 16 "mixed-fixed-type-aliases.cpp2"
     my::u16 y {42}; 

regression-tests/test-results/msvc-2022/pure2-main-args.cpp.execution

@@ -1 +1,3 @@
-args.argc is 1, and args.argv[0] is test.exe
+args.argc            is 1
+args.argv[0]         is test.exe
+args.mutable_argv[0] is test.exe

regression-tests/test-results/pure2-bugfix-for-discard-precedence.cpp

@@ -26,7 +26,7 @@ class quantity {
 #line 5 "pure2-bugfix-for-discard-precedence.cpp2"
 };
 
-auto main(int const argc_, char const* const* const argv_) -> int;
+auto main(int const argc_, char** argv_) -> int;
 
 
 //=== Cpp2 function definitions =================================================
@@ -46,7 +46,7 @@ auto main(int const argc_, char const* const* const argv_) -> int;
   [[nodiscard]] auto quantity::operator+(quantity const& that) -> quantity { return quantity(number + that.number);  }
 
 #line 7 "pure2-bugfix-for-discard-precedence.cpp2"
-auto main(int const argc_, char const* const* const argv_) -> int{
+auto main(int const argc_, char** argv_) -> int{
   auto args = cpp2::make_args(argc_, argv_); 
 #line 8 "pure2-bugfix-for-discard-precedence.cpp2"
   quantity x {1729}; 

regression-tests/test-results/pure2-initialization-safety-with-else-if.cpp

@@ -11,13 +11,13 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "pure2-initialization-safety-with-else-if.cpp2"
-auto main(int const argc_, char const* const* const argv_) -> int;
+auto main(int const argc_, char** argv_) -> int;
 
 
 //=== Cpp2 function definitions =================================================
 
 #line 1 "pure2-initialization-safety-with-else-if.cpp2"
-auto main(int const argc_, char const* const* const argv_) -> int{
+auto main(int const argc_, char** argv_) -> int{
     auto args = cpp2::make_args(argc_, argv_); 
 #line 2 "pure2-initialization-safety-with-else-if.cpp2"
     cpp2::deferred_init<int*> p; 

regression-tests/test-results/pure2-main-args.cpp

@@ -11,14 +11,17 @@
 //=== Cpp2 type definitions and function declarations ===========================
 
 #line 1 "pure2-main-args.cpp2"
-auto main(int const argc_, char const* const* const argv_) -> int;
+auto main(int const argc_, char** argv_) -> int;
 
 
 //=== Cpp2 function definitions =================================================
 
 #line 1 "pure2-main-args.cpp2"
-auto main(int const argc_, char const* const* const argv_) -> int { 
+auto main(int const argc_, char** argv_) -> int { 
     auto args = cpp2::make_args(argc_, argv_); 
 #line 2 "pure2-main-args.cpp2"
-    std::cout << "args.argc is " + cpp2::to_string(args.argc) + ", and args.argv[0] is " + cpp2::to_string(cpp2::assert_in_bounds(args.argv, 0)) + "\n";  }
+    std::cout 
+        << "args.argc            is " + cpp2::to_string(args.argc) + "\n" 
+        << "args.argv[0]         is " + cpp2::to_string(cpp2::assert_in_bounds(args.argv, 0)) + "\n" 
+        << "args.mutable_argv[0] is " + cpp2::to_string(cpp2::assert_in_bounds(args.mutable_argv, 0)) + "\n"; }
 

regression-tests/test-results/pure2-statement-scope-parameters.cpp

@@ -12,14 +12,14 @@
 
 
 #line 2 "pure2-statement-scope-parameters.cpp2"
-auto main(int const argc_, char const* const* const argv_) -> int;
+auto main(int const argc_, char** argv_) -> int;
 
 
 //=== Cpp2 function definitions =================================================
 
 
 #line 2 "pure2-statement-scope-parameters.cpp2"
-auto main(int const argc_, char const* const* const argv_) -> int{
+auto main(int const argc_, char** argv_) -> int{
     auto args = cpp2::make_args(argc_, argv_); 
 #line 3 "pure2-statement-scope-parameters.cpp2"
     auto local_int {42}; 

regression-tests/test-results/version

@@ -1,5 +1,5 @@
 
-cppfront compiler v0.2.1   Build 8812:1816
+cppfront compiler v0.2.1   Build 8814:1300
 Copyright(c) Herb Sutter   All rights reserved
 
 SPDX-License-Identifier: CC-BY-NC-ND-4.0

source/build.info

@@ -1 +1 @@
-"8812:1816"
+"8814:1300"

source/cppfront.cpp

@@ -4260,7 +4260,7 @@ class cppfront
             )
         {
             printer.print_cpp2(
-                "(int const argc_, char const* const* const argv_)",
+                "(int const argc_, char** argv_)",
                 n.parameters->position()
             );
             current_functions.back().prolog.statements.push_back(