Add initial to_string, operator<<, set, and clear for enumerations

Author: hsutter

include/cpp2util.h

@@ -553,8 +553,8 @@ using in =
 //
 template<typename T>
 class deferred_init {
-    bool init = false;
     alignas(T) std::byte data[sizeof(T)]; // or: std::aligned_storage_t<sizeof(T), alignof(T)> data
+    bool init = false;
 
     auto t() -> T& { return *std::launder(reinterpret_cast<T*>(&data)); }
 
@@ -1584,6 +1584,12 @@ class strict_value {
 
     auto operator<=>( strict_value const& ) const -> std::strong_ordering = default;
 
+    auto to_string() const -> std::string { return Tag::to_string(*this); }
+
+    friend auto operator<<(std::ostream& o, strict_value const& v) -> std::ostream& { return o << v.to_string(); }
+
+    //  Bitwise operations
+
     auto operator|=( strict_value const& that )       -> strict_value requires BitwiseOps { t |= that.t; return *this; }
     auto operator&=( strict_value const& that )       -> strict_value requires BitwiseOps { t &= that.t; return *this; }
     auto operator^=( strict_value const& that )       -> strict_value requires BitwiseOps { t ^= that.t; return *this; }
@@ -1592,7 +1598,8 @@ class strict_value {
     auto operator& ( strict_value const& that ) const -> strict_value requires BitwiseOps { return strict_value(t & that.t); }
     auto operator^ ( strict_value const& that ) const -> strict_value requires BitwiseOps { return strict_value(t ^ that.t); }
 
-    auto is_default_value() const -> bool { return t == T{}; }
+    auto set       ( strict_value const& that )       -> void         requires BitwiseOps { t |=  that.t; }
+    auto clear     ( strict_value const& that )       -> void         requires BitwiseOps { t &= ~that.t; }
 };
 
 template <typename T, typename Tag>

regression-tests/pure2-enum.cpp2

@@ -28,6 +28,9 @@ main: () = {
     // if x == 9 { }                    // error, can't compare skat_game and integer
     // if x == rgb::red { }             // error, can't compare skat_game and rgb color
 
+    std::cout << "x.to_string() is (x.to_string())$\n";
+    std::cout << "using << prints " << x << "\n";
+
     std::cout << "with if else: ";
     if x == skat_game::diamonds {       // ok, can compare two skat_games
         std::cout << "diamonds";
@@ -51,7 +54,7 @@ main: () = {
         is (skat_game::spades  ) = "spades";
         is (skat_game::clubs   ) = "clubs";
         is _ = "not a suit";
-    } << std::endl;
+    } << "\n\n";
 
     // x = 9;                           // error, can't assign skat_game from integer
     // x = rgb::red;                    // error, can't assign skat_game from rgb color
@@ -69,7 +72,8 @@ main: () = {
     std::cout << "f  is (f2) is (f  is (f2))$\n";
     std::cout << "f2 is (f ) is (f2 is (f ))$\n\n";
 
-    f  |= file_attributes::current;
+    f.clear( f2 );
+    f.set( file_attributes::current | f2 );
     f  |= file_attributes::obsolete;
     f2 |= file_attributes::current;
 
@@ -83,6 +87,6 @@ main: () = {
     std::cout << "inspecting: " << inspect f -> std::string {
         is (file_attributes::current) = "exactly 'current'";
         is (cpp2::has_flags(f2))      = "includes all f2's flags ('cached' and 'current')";
-        is _                          = "no match";
+        is _                          = "something else";
     } << "\n";
 }

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

@@ -1,5 +1,8 @@
+x.to_string() is clubs
+using << prints clubs
 with if else: clubs
 with inspect: clubs
+
 f  as int  is 1
 f2 as int  is 1
 f  is (f2) is 1

regression-tests/test-results/gcc-10/pure2-bugfix-for-requires-clause-in-forward-declaration.cpp.output

@@ -1,13 +1,13 @@
 pure2-bugfix-for-requires-clause-in-forward-declaration.cpp2:3:36: error: expected ‘;’ at end of member declaration
 In file included from pure2-bugfix-for-requires-clause-in-forward-declaration.cpp:7:
-../../../include/cpp2util.h:1794:47: error: static assertion failed: GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.
- 1794 |     #define CPP2_REQUIRES_(...) static_assert(false, "GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.")
+../../../include/cpp2util.h:1801:47: error: static assertion failed: GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.
+ 1801 |     #define CPP2_REQUIRES_(...) static_assert(false, "GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.")
       |                                               ^~~~~
 pure2-bugfix-for-requires-clause-in-forward-declaration.cpp2:4:1: note: in expansion of macro ‘CPP2_REQUIRES_’
 pure2-bugfix-for-requires-clause-in-forward-declaration.cpp2:3:46: error: expected ‘;’ at end of member declaration
 In file included from pure2-bugfix-for-requires-clause-in-forward-declaration.cpp:7:
-../../../include/cpp2util.h:1794:47: error: static assertion failed: GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.
- 1794 |     #define CPP2_REQUIRES_(...) static_assert(false, "GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.")
+../../../include/cpp2util.h:1801:47: error: static assertion failed: GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.
+ 1801 |     #define CPP2_REQUIRES_(...) static_assert(false, "GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.")
       |                                               ^~~~~
 pure2-bugfix-for-requires-clause-in-forward-declaration.cpp2:4:1: note: in expansion of macro ‘CPP2_REQUIRES_’
 pure2-bugfix-for-requires-clause-in-forward-declaration.cpp2:3:3: error: no declaration matches ‘element::element(auto:80&&) requires  is_same_v<typename std::remove_cv<typename std::remove_reference<decltype(element::__ct ::n)>::type>::type, std::__cxx11::string>’

regression-tests/test-results/gcc-10/pure2-enum.cpp.execution

@@ -1,5 +1,8 @@
+x.to_string() is clubs
+using << prints clubs
 with if else: clubs
 with inspect: clubs
+
 f  as int  is 1
 f2 as int  is 1
 f  is (f2) is 1

regression-tests/test-results/gcc-10/pure2-requires-clauses.cpp.output

@@ -1,5 +1,5 @@
 In file included from pure2-requires-clauses.cpp:7:
-../../../include/cpp2util.h:1794:33: error: expected unqualified-id before ‘static_assert’
- 1794 |     #define CPP2_REQUIRES_(...) static_assert(false, "GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.")
+../../../include/cpp2util.h:1801:33: error: expected unqualified-id before ‘static_assert’
+ 1801 |     #define CPP2_REQUIRES_(...) static_assert(false, "GCC 11 or higher is required to support variables and type-scope functions that have a 'requires' clause. This includes a type-scope 'forward' parameter of non-wildcard type, such as 'func: (this, forward s: std::string)', which relies on being able to add a 'requires' clause - in that case, use 'forward s: _' instead if you need the result to compile with GCC 10.")
       |                                 ^~~~~~~~~~~~~
 pure2-requires-clauses.cpp2:19:1: note: in expansion of macro ‘CPP2_REQUIRES_’

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

@@ -1,5 +1,8 @@
+x.to_string() is clubs
+using << prints clubs
 with if else: clubs
 with inspect: clubs
+
 f  as int  is 1
 f2 as int  is 1
 f  is (f2) is 1

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

@@ -1,5 +1,8 @@
+x.to_string() is clubs
+using << prints clubs
 with if else: clubs
 with inspect: clubs
+
 f  as int  is 1
 f2 as int  is 1
 f  is (f2) is 1

regression-tests/test-results/pure2-enum.cpp

@@ -30,6 +30,8 @@ public: auto static constexpr spades = cpp2::strict_value<cpp2::i8,skat_game,0>(
 public: auto static constexpr clubs = cpp2::strict_value<cpp2::i8,skat_game,0>(12);
 public: auto static constexpr grand = cpp2::strict_value<cpp2::i8,skat_game,0>(20);
 public: auto static constexpr null = cpp2::strict_value<cpp2::i8,skat_game,0>(23);
+public: [[nodiscard]] static auto size() -> auto;
+public: [[nodiscard]] static auto to_string(cpp2::in<cpp2::strict_value<cpp2::i8,skat_game,0>> value) -> std::string;
 public: [[nodiscard]] auto operator<=>([[maybe_unused]] skat_game const& that) const& -> std::strong_ordering = default;
 public: skat_game([[maybe_unused]] skat_game const& that);
 
@@ -50,6 +52,8 @@ class rgb {
 public: auto static constexpr red = cpp2::strict_value<cpp2::i8,rgb,0>(0);
 public: auto static constexpr green = cpp2::strict_value<cpp2::i8,rgb,0>(1);
 public: auto static constexpr blue = cpp2::strict_value<cpp2::i8,rgb,0>(2);
+public: [[nodiscard]] static auto size() -> auto;
+public: [[nodiscard]] static auto to_string(cpp2::in<cpp2::strict_value<cpp2::i8,rgb,0>> value) -> std::string;
 public: [[nodiscard]] auto operator<=>([[maybe_unused]] rgb const& that) const& -> std::strong_ordering = default;
 public: rgb([[maybe_unused]] rgb const& that);
 
@@ -70,6 +74,8 @@ public: auto static constexpr cached = cpp2::strict_value<cpp2::u8,file_attribut
 public: auto static constexpr current = cpp2::strict_value<cpp2::u8,file_attributes,1>(2);
 public: auto static constexpr obsolete = cpp2::strict_value<cpp2::u8,file_attributes,1>(4);
 public: auto static constexpr none = cpp2::strict_value<cpp2::u8,file_attributes,1>(0);
+public: [[nodiscard]] static auto size() -> auto;
+public: [[nodiscard]] static auto to_string(cpp2::in<cpp2::strict_value<cpp2::u8,file_attributes,1>> value) -> std::string;
 public: [[nodiscard]] auto operator<=>([[maybe_unused]] file_attributes const& that) const& -> std::strong_ordering = default;
 public: file_attributes([[maybe_unused]] file_attributes const& that);
 
@@ -92,6 +98,18 @@ auto main() -> int;
 
 
 
+    #line 1 "pure2-enum.cpp2"
+[[nodiscard]] auto skat_game::size() -> auto { return 6; }
+[[nodiscard]] auto skat_game::to_string(cpp2::in<cpp2::strict_value<cpp2::i8,skat_game,0>> value) -> std::string{
+    if (value == diamonds) {return "diamonds"; }
+    if (value == hearts) {return "hearts"; }
+    if (value == spades) {return "spades"; }
+    if (value == clubs) {return "clubs"; }
+    if (value == grand) {return "grand"; }
+    if (value == null) {return "null"; }
+    return "(invalid skat_game enumerator value)"; 
+    }
+
     #line 1 "pure2-enum.cpp2"
 skat_game::skat_game([[maybe_unused]] skat_game const& that){}
 auto skat_game::operator=([[maybe_unused]] skat_game const& that) -> skat_game& {
@@ -100,14 +118,31 @@ skat_game::skat_game([[maybe_unused]] skat_game&& that) noexcept{}
 auto skat_game::operator=([[maybe_unused]] skat_game&& that) noexcept -> skat_game& {
                                 return *this;}
 skat_game::skat_game(){}
-rgb::rgb([[maybe_unused]] rgb const& that){}
+[[nodiscard]] auto rgb::size() -> auto { return 3; }
+[[nodiscard]] auto rgb::to_string(cpp2::in<cpp2::strict_value<cpp2::i8,rgb,0>> value) -> std::string{
+    if (value == red) {return "red"; }
+    if (value == green) {return "green"; }
+    if (value == blue) {return "blue"; }
+    return "(invalid rgb enumerator value)"; 
+    }
+
+    rgb::rgb([[maybe_unused]] rgb const& that){}
 auto rgb::operator=([[maybe_unused]] rgb const& that) -> rgb& {
                                 return *this;}
 rgb::rgb([[maybe_unused]] rgb&& that) noexcept{}
 auto rgb::operator=([[maybe_unused]] rgb&& that) noexcept -> rgb& {
                                 return *this;}
 rgb::rgb(){}
-file_attributes::file_attributes([[maybe_unused]] file_attributes const& that){}
+[[nodiscard]] auto file_attributes::size() -> auto { return 4; }
+[[nodiscard]] auto file_attributes::to_string(cpp2::in<cpp2::strict_value<cpp2::u8,file_attributes,1>> value) -> std::string{
+    if (value == cached) {return "cached"; }
+    if (value == current) {return "current"; }
+    if (value == obsolete) {return "obsolete"; }
+    if (value == none) {return "none"; }
+    return "(invalid file_attributes enumerator value)"; 
+    }
+
+    file_attributes::file_attributes([[maybe_unused]] file_attributes const& that){}
 auto file_attributes::operator=([[maybe_unused]] file_attributes const& that) -> file_attributes& {
                                 return *this;}
 file_attributes::file_attributes([[maybe_unused]] file_attributes&& that) noexcept{}
@@ -123,6 +158,9 @@ auto main() -> int{
     // if x == 9 { }                    // error, can't compare skat_game and integer
     // if x == rgb::red { }             // error, can't compare skat_game and rgb color
 
+    std::cout << "x.to_string() is " + cpp2::to_string(CPP2_UFCS_0(to_string, x)) + "\n";
+    std::cout << "using << prints " << x << "\n";
+
     std::cout << "with if else: ";
     if (x == skat_game::diamonds) {     // ok, can compare two skat_games
         std::cout << "diamonds";
@@ -146,7 +184,7 @@ auto main() -> int{
         else if (cpp2::is(__expr, skat_game::spades)) { if constexpr( requires{"spades";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(("spades")),std::string> ) return "spades"; else return std::string{}; else return std::string{}; }
         else if (cpp2::is(__expr, skat_game::clubs)) { if constexpr( requires{"clubs";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(("clubs")),std::string> ) return "clubs"; else return std::string{}; else return std::string{}; }
         else return "not a suit"; }
-    () << std::endl;
+    () << "\n\n";
 
     // x = 9;                           // error, can't assign skat_game from integer
     // x = rgb::red;                    // error, can't assign skat_game from rgb color
@@ -164,7 +202,8 @@ auto main() -> int{
     std::cout << "f  is (f2) is " + cpp2::to_string(cpp2::is(f, (f2))) + "\n";
     std::cout << "f2 is (f ) is " + cpp2::to_string(cpp2::is(f2, (f))) + "\n\n";
 
-    f  |= file_attributes::current;
+    CPP2_UFCS(clear, f, f2);
+    CPP2_UFCS(set, f, file_attributes::current | f2);
     f  |= file_attributes::obsolete;
     f2 |= file_attributes::current;
 
@@ -178,7 +217,7 @@ auto main() -> int{
     std::cout << "inspecting: " << [&] () -> std::string { auto&& __expr = std::move(f);
         if (cpp2::is(__expr, (file_attributes::current))) { if constexpr( requires{"exactly 'current'";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(("exactly 'current'")),std::string> ) return "exactly 'current'"; else return std::string{}; else return std::string{}; }
         else if (cpp2::is(__expr, cpp2::has_flags(std::move(f2)))) { if constexpr( requires{"includes all f2's flags ('cached' and 'current')";} ) if constexpr( std::is_convertible_v<CPP2_TYPEOF(("includes all f2's flags ('cached' and 'current')")),std::string> ) return "includes all f2's flags ('cached' and 'current')"; else return std::string{}; else return std::string{}; }
-        else return "no match"; }
+        else return "something else"; }
     () << "\n";
 }
 

regression-tests/test-results/version

@@ -1,5 +1,5 @@
 
-cppfront compiler v0.2.1   Build 8905:1016
+cppfront compiler v0.2.1   Build 8906:1741
 Copyright(c) Herb Sutter   All rights reserved
 
 SPDX-License-Identifier: CC-BY-NC-ND-4.0