Allow flag enumerators with multiple flags set (aka groups)

Author: hsutter

regression-tests/pure2-enum.cpp2

@@ -18,6 +18,7 @@ file_attributes: @flag_enum type = {
     cached;   // 1
     current;  // 2
     obsolete; // 4
+    cached_and_current := 3;
 }
 
 main: () = {
@@ -61,7 +62,7 @@ main: () = {
 
     x = skat_game::diamonds;        // ok, can assign one skat_game from another
 
-    f := file_attributes::current | file_attributes::cached;
+    f := file_attributes::cached_and_current;
     f &= file_attributes::cached  | file_attributes::obsolete;
 
     f2 := file_attributes::cached;

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

@@ -8,8 +8,8 @@ f2 as int  is 1
 f  is (f2) is 1
 f2 is (f ) is 1
 
-f  is (cached, current, obsolete)
-f2 is (cached, current)
+f  is (cached, current, obsolete, cached_and_current)
+f2 is (cached, current, cached_and_current)
 f  as int  is 7
 f2 as int  is 3
 f  == f2   is 0

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

@@ -8,8 +8,8 @@ f2 as int  is 1
 f  is (f2) is 1
 f2 is (f ) is 1
 
-f  is (cached, current, obsolete)
-f2 is (cached, current)
+f  is (cached, current, obsolete, cached_and_current)
+f2 is (cached, current, cached_and_current)
 f  as int  is 7
 f2 as int  is 3
 f  == f2   is 0

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

@@ -8,8 +8,8 @@ f2 as int  is 1
 f  is (f2) is 1
 f2 is (f ) is 1
 
-f  is (cached, current, obsolete)
-f2 is (cached, current)
+f  is (cached, current, obsolete, cached_and_current)
+f2 is (cached, current, cached_and_current)
 f  as int  is 7
 f2 as int  is 3
 f  == f2   is 0

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

@@ -8,8 +8,8 @@ f2 as int  is 1
 f  is (f2) is 1
 f2 is (f ) is 1
 
-f  is (cached, current, obsolete)
-f2 is (cached, current)
+f  is (cached, current, obsolete, cached_and_current)
+f2 is (cached, current, cached_and_current)
 f  as int  is 7
 f2 as int  is 3
 f  == f2   is 0

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

@@ -73,6 +73,7 @@ class file_attributes {
 public: auto static constexpr cached = cpp2::strict_value<cpp2::u8,file_attributes,1>(1);
 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 cached_and_current = cpp2::strict_value<cpp2::u8,file_attributes,1>(3);
 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;
@@ -88,7 +89,8 @@ public: explicit file_attributes();
               // 1
               // 2
               // 4
-#line 21 "pure2-enum.cpp2"
+
+#line 22 "pure2-enum.cpp2"
 };
 
 auto main() -> int;
@@ -142,14 +144,15 @@ rgb::rgb([[maybe_unused]] rgb&& that) noexcept{}
 auto rgb::operator=([[maybe_unused]] rgb&& that) noexcept -> rgb& {
                                 return *this;}
 rgb::rgb(){}
-[[nodiscard]] auto file_attributes::size() -> auto { return 4; }
+[[nodiscard]] auto file_attributes::size() -> auto { return 5; }
 [[nodiscard]] auto file_attributes::to_string(cpp2::in<cpp2::strict_value<cpp2::u8,file_attributes,1>> value) -> std::string{
 
 std::string ret {}; 
 ret = "(";
 if (CPP2_UFCS(has, value, cached)) {ret += "cached";}
 if (CPP2_UFCS(has, value, current)) {ret += std::string(", ") + "current";}
 if (CPP2_UFCS(has, value, obsolete)) {ret += std::string(", ") + "obsolete";}
+if (CPP2_UFCS(has, value, cached_and_current)) {ret += std::string(", ") + "cached_and_current";}
 if (CPP2_UFCS(has, value, none)) {ret += std::string(", ") + "none";}
 if (CPP2_UFCS_0(empty, ret)) {ret = "(invalid file_attributes enumerator value)";}
 return ret + ")"; 
@@ -162,7 +165,7 @@ file_attributes::file_attributes([[maybe_unused]] file_attributes&& that) noexce
 auto file_attributes::operator=([[maybe_unused]] file_attributes&& that) noexcept -> file_attributes& {
                                 return *this;}
 file_attributes::file_attributes(){}
-#line 23 "pure2-enum.cpp2"
+#line 24 "pure2-enum.cpp2"
 auto main() -> int{
     // x : skat_game = 9;               // error, can't construct skat_game from integer
 
@@ -204,7 +207,7 @@ auto main() -> int{
 
     x = skat_game::diamonds;        // ok, can assign one skat_game from another
 
-    auto f {file_attributes::current | file_attributes::cached}; 
+    auto f {file_attributes::cached_and_current}; 
     f &= file_attributes::cached  | file_attributes::obsolete;
 
     auto f2 {file_attributes::cached}; 

regression-tests/test-results/version

@@ -1,5 +1,5 @@
 
-cppfront compiler v0.2.1   Build 8909:1522
+cppfront compiler v0.2.1   Build 8909:1547
 Copyright(c) Herb Sutter   All rights reserved
 
 SPDX-License-Identifier: CC-BY-NC-ND-4.0

source/build.info

@@ -1 +1 @@
-"8909:1522"
+"8909:1547"

source/reflect.h

@@ -38,7 +38,7 @@ class alias_declaration;
 #line 807 "reflect.h2"
 class enumerator_info;
 
-#line 1017 "reflect.h2"
+#line 1014 "reflect.h2"
 }
 }
 
@@ -630,8 +630,8 @@ struct basic_enum__ret { std::string underlying_type; std::string strict_underly
 //-----------------------------------------------------------------------
 //
 //    "An enum[...] is a totally ordered value type that stores a
-//     value of its enumerators’s type, and otherwise has only public
-//     member variables of its enumerators’s type, all of which are
+//     value of its enumerators's type, and otherwise has only public
+//     member variables of its enumerator's type, all of which are
 //     naturally scoped because they are members of a type."
 // 
 //          -- P0707R4, section 3
@@ -642,7 +642,7 @@ auto cpp2_enum(meta::type_declaration& t) -> void;
 //-----------------------------------------------------------------------
 //
 //     "flag_enum expresses an enumeration that stores values 
-//      corresponding to bitwise-or’d enumerators. The enumerators must
+//      corresponding to bitwise-or'd enumerators. The enumerators must
 //      be powers of two, and are automatically generated [...] A none
 //      value is provided [...] Operators | and & are provided to
 //      combine and extract values."
@@ -651,7 +651,7 @@ auto cpp2_enum(meta::type_declaration& t) -> void;
 //
 auto flag_enum(meta::type_declaration& t) -> void;
 
-#line 1015 "reflect.h2"
+#line 1012 "reflect.h2"
 //=======================================================================
 //  Switch to Cpp1 and close subnamespace meta
 }
@@ -1492,12 +1492,9 @@ auto flag_enum(meta::type_declaration& t) -> void
 
     //  Let basic_enum do its thing, with a power-of-two value generator
     static_cast<void>(CPP2_UFCS(basic_enum, t, 
-        [_0 = t](cpp2::i64& value, cpp2::in<std::string> specified_value) -> void{
+        [](cpp2::i64& value, cpp2::in<std::string> specified_value) -> void{
             if (!(CPP2_UFCS_0(empty, specified_value))) {
                 value = std::strtoll(&cpp2::assert_in_bounds(specified_value, 0), nullptr, 10);
-                if ((value & (value - 1)) != 0) {
-                    CPP2_UFCS(error, _0, "a flag_enum value must be a power of two");
-                }
             }else {
                 if (cpp2::cmp_less(value,1)) {
                     value = 1;
@@ -1511,7 +1508,7 @@ auto flag_enum(meta::type_declaration& t) -> void
     ));
 }
 
-#line 1017 "reflect.h2"
+#line 1014 "reflect.h2"
 }
 }
 

source/reflect.h2

@@ -995,9 +995,6 @@ flag_enum: (inout t: meta::type_declaration) =
         :(inout value: i64, specified_value: std::string) = {
             if !specified_value.empty() {
                 value = std::strtoll(specified_value[0]&, nullptr, 10);
-                if (value & (value - 1)) != 0 {
-                    t$.error( "a flag_enum value must be a power of two" );
-                }
             } else {
                 if value < 1 {
                     value = 1;