fix(to_cpp1): direct-initialize statement parameter and constexpr variable

regression-tests/pure2-print.cpp2

@@ -77,6 +77,7 @@ outer: @print type = {
 
         object_alias_1: i8 == 42;
         object_alias_2: == 42;
+        object_alias_3: std::array == (4,5,6);
 
 
         var: ::outer::mytype = ();

regression-tests/pure2-statement-scope-parameters.cpp2

@@ -12,4 +12,9 @@ main: (args) = {
         i++;
     }
     std::cout << local_int << "\n";     // prints 43
+
+    _: std::chrono::duration<i32> = 0;
+    (copy _: std::chrono::duration<i32> = 0) { }
+    _: std::in_place_t = ();
+    (copy _: std::in_place_t = ()) { }
 }

regression-tests/test-results/pure2-bugfix-for-ufcs-name-lookup.cpp

@@ -78,12 +78,12 @@ auto main() -> int{
     if (cpp2::Default.has_handler() && !(std::move(f) == 0) ) { cpp2::Default.report_violation(""); }
   }
 {
-auto const& f = t().f();
+auto const& f{t().f()};
 #line 33 "pure2-bugfix-for-ufcs-name-lookup.cpp2"
   if (cpp2::Default.has_handler() && !(f == 0) ) { cpp2::Default.report_violation(""); }
 }
 {
-auto const& f = t().f();
+auto const& f{t().f()};
 #line 34 "pure2-bugfix-for-ufcs-name-lookup.cpp2"
   if (cpp2::Default.has_handler() && !(f == 0) ) { cpp2::Default.report_violation(""); }
 }
@@ -113,12 +113,12 @@ auto const& f = t().f();
   {
     auto f {[]() mutable -> void{
 {
-cpp2::in<identity> f = identity();
+cpp2::in<identity> f{identity()};
 #line 59 "pure2-bugfix-for-ufcs-name-lookup.cpp2"
       if (cpp2::Default.has_handler() && !(CPP2_UFCS(f)(t()) == 0) ) { cpp2::Default.report_violation(""); }
 }
 {
-cpp2::in<identity> f = identity();
+cpp2::in<identity> f{identity()};
 #line 60 "pure2-bugfix-for-ufcs-name-lookup.cpp2"
       static_cast<void>(CPP2_UFCS(f)(u()));
 }

regression-tests/test-results/pure2-bugfix-for-unbraced-function-expression.cpp

@@ -40,12 +40,12 @@ extern cpp2::i32 y;
 #line 5 "pure2-bugfix-for-unbraced-function-expression.cpp2"
 [[nodiscard]] auto main() -> int{
 {
-auto const& x = t();
+auto const& x{t()};
 #line 6 "pure2-bugfix-for-unbraced-function-expression.cpp2"
   {CPP2_ASSERT_IN_BOUNDS(x, []() mutable -> auto { return 0;  }); }
 }
 {
-auto const& x = t();
+auto const& x{t()};
 #line 7 "pure2-bugfix-for-unbraced-function-expression.cpp2"
   {CPP2_ASSERT_IN_BOUNDS(x, []() mutable -> auto { return 0;  }); }
 }

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

@@ -39,7 +39,7 @@ class item {
 #line 9 "pure2-interpolation.cpp2"
 [[nodiscard]] auto main() -> int{
 {
-auto const& x = 0;
+auto const& x{0};
 
 #line 11 "pure2-interpolation.cpp2"
     {
@@ -57,7 +57,7 @@ auto const& x = 0;
     }
 }
 {
-auto const& x = item();
+auto const& x{item()};
 
 #line 25 "pure2-interpolation.cpp2"
     {

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

@@ -55,27 +55,27 @@ CPP2_REQUIRES_ ((std::is_convertible_v<CPP2_TYPEOF(x), int> && ...)) ;
 
     public: static auto test() -> void;
 
-#line 91 "pure2-print.cpp2"
+#line 92 "pure2-print.cpp2"
     public: template<typename ...Ts> class x {
         private: std::tuple<Ts...> tup {}; 
         public: x() = default;
         public: x(x const&) = delete; /* No 'that' constructor, suppress copy */
         public: auto operator=(x const&) -> void = delete;
 
-#line 93 "pure2-print.cpp2"
+#line 94 "pure2-print.cpp2"
     };
 
     public: template<typename ...Args> static auto print(std::ostream& out, Args const& ...args) -> void
 CPP2_REQUIRES_ (cpp2::cmp_greater_eq(sizeof...(Args),0u)) ;
 
-#line 99 "pure2-print.cpp2"
+#line 100 "pure2-print.cpp2"
     public: template<typename ...Args> [[nodiscard]] static auto all(Args const& ...args) -> bool;
     public: outer() = default;
     public: outer(outer const&) = delete; /* No 'that' constructor, suppress copy */
     public: auto operator=(outer const&) -> void = delete;
 
 
-#line 102 "pure2-print.cpp2"
+#line 103 "pure2-print.cpp2"
 };
 
 auto main() -> int;
@@ -169,8 +169,9 @@ requires ((std::is_convertible_v<CPP2_TYPEOF(x), int> && ...)) {(std::cout << ..
 
         cpp2::i8 constexpr object_alias_1 = 42;
         auto constexpr object_alias_2 = 42;
+        std::array constexpr object_alias_3{ 4, 5, 6 };
 
-#line 82 "pure2-print.cpp2"
+#line 83 "pure2-print.cpp2"
         ::outer::mytype var {}; 
         cout << CPP2_UFCS(g)(var, 42) << "\n";
 
@@ -180,17 +181,17 @@ requires ((std::is_convertible_v<CPP2_TYPEOF(x), int> && ...)) {(std::cout << ..
         () << "\n";
     }
 
-#line 95 "pure2-print.cpp2"
+#line 96 "pure2-print.cpp2"
     template<typename ...Args> auto outer::print(std::ostream& out, Args const& ...args) -> void
 requires (cpp2::cmp_greater_eq(sizeof...(Args),0u)) {
-#line 96 "pure2-print.cpp2"
+#line 97 "pure2-print.cpp2"
         (out << ... << args);
     }
 
     template<typename ...Args> [[nodiscard]] auto outer::all(Args const& ...args) -> bool { 
         return (... && args);  }
 
-#line 104 "pure2-print.cpp2"
+#line 105 "pure2-print.cpp2"
 auto main() -> int{
     outer::test();
 }

regression-tests/test-results/pure2-print.cpp2.output

@@ -124,6 +124,7 @@ outer:/* @print */ type =
         type_alias: type == array<int, 10>;
         object_alias_1: i8 == 42;
         object_alias_2: == 42;
+        object_alias_3: std::array == (4, 5, 6);
         var: ::outer::mytype = ();
         cout << var.g(42) << "\n";
         cout << inspect var.g(42) -> namespace_alias::string {

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

@@ -26,7 +26,7 @@ auto main(int const argc_, char** argv_) -> int{
 #line 3 "pure2-statement-scope-parameters.cpp2"
     auto local_int {42}; 
 {
-auto const& i = local_int;
+auto const& i{local_int};
 
     //  'in' (read-only) statement scope variable
 #line 6 "pure2-statement-scope-parameters.cpp2"
@@ -35,7 +35,7 @@ auto const& i = local_int;
     }
 }
 {
-auto& i = local_int;
+auto& i{local_int};
 
     //  'inout' (read-write) statement scope variable
 #line 11 "pure2-statement-scope-parameters.cpp2"
@@ -45,5 +45,20 @@ auto& i = local_int;
 }
 #line 14 "pure2-statement-scope-parameters.cpp2"
     std::cout << std::move(local_int) << "\n";// prints 43
+
+    std::chrono::duration<cpp2::i32> auto_16_5 {0}; 
+{
+[[maybe_unused]] std::chrono::duration<cpp2::i32> unnamed_param_1{0};
+#line 17 "pure2-statement-scope-parameters.cpp2"
+    {}
+}
+#line 18 "pure2-statement-scope-parameters.cpp2"
+    std::in_place_t auto_18_5 {}; 
+{
+[[maybe_unused]] std::in_place_t unnamed_param_1{};
+#line 19 "pure2-statement-scope-parameters.cpp2"
+    {}
+}
+#line 20 "pure2-statement-scope-parameters.cpp2"
 }
 

regression-tests/test-results/pure2-type-and-namespace-aliases.cpp

@@ -73,7 +73,7 @@ namespace N {
 auto myfunc() -> void{
     N1::pmr_vec<myclass::str> v {"xyzzy", "plugh"}; 
 {
-auto const& v2 = std::move(v);
+auto const& v2{std::move(v)};
 
 #line 21 "pure2-type-and-namespace-aliases.cpp2"
     for ( auto const& s : v2 ) 

source/reflect.h

@@ -818,7 +818,7 @@ namespace meta {
             static_cast<void>(CPP2_UFCS(emplace_back)((*cpp2::assert_not_null(_1)), s, source_line::category::cpp2));
         }}; 
 {
-auto newline_pos = CPP2_UFCS(find)(source, '\n');
+auto newline_pos{CPP2_UFCS(find)(source, '\n')};
 
         //  First split this string into source_lines
         //
@@ -1483,7 +1483,7 @@ auto basic_enum(
 
     auto found_non_numeric {false}; 
 {
-std::string value = "-1";
+std::string value{"-1"};
 
 #line 957 "reflect.h2"
     for ( 
@@ -1613,7 +1613,7 @@ std::string value = "-1";
     CPP2_UFCS(add_member)(t, "    operator=         : (out this, that) == { }");
     CPP2_UFCS(add_member)(t, "    operator<=>       : (this, that) -> std::strong_ordering;");
 {
-std::string to_string = "    to_string: (this) -> std::string = { \n";
+std::string to_string{"    to_string: (this) -> std::string = { \n"};
 
     //  Provide a 'to_string' function to print enumerator name(s)
 
@@ -1696,7 +1696,7 @@ auto cpp2_union(meta::type_declaration& t) -> void
 {
     std::vector<value_member_info> alternatives {}; 
 {
-auto value = 0;
+auto value{0};
 
     //  1. Gather: All the user-written members, and find/compute the max size
 
@@ -1745,14 +1745,14 @@ auto value = 0;
 
     CPP2_UFCS(remove_marked_members)(t);
 {
-std::string storage = "    _storage: cpp2::aligned_storage<cpp2::max( ";
+std::string storage{"    _storage: cpp2::aligned_storage<cpp2::max( "};
 
     //  Provide storage
 
 #line 1250 "reflect.h2"
     {
 {
-std::string comma = "";
+std::string comma{""};
 
 #line 1252 "reflect.h2"
         for ( 
@@ -1765,7 +1765,7 @@ std::string comma = "";
 #line 1258 "reflect.h2"
         storage += "), cpp2::max( ";
 {
-std::string comma = "";
+std::string comma{""};
 
 #line 1261 "reflect.h2"
         for ( 
@@ -1800,7 +1800,7 @@ std::string comma = "";
         CPP2_UFCS(add_member)(t, "    set_" + cpp2::to_string(a.name) + ": (inout this, forward _args...: _) = { if !is_" + cpp2::to_string(a.name) + "() { _destroy(); std::construct_at( reinterpret_cast<*" + cpp2::to_string(a.type) + ">(_storage&), _args...); } else { reinterpret_cast<*" + cpp2::to_string(a.type) + ">(_storage&)* = :" + cpp2::to_string(a.type) + " = (_args...); } _discriminator = " + cpp2::to_string(a.value) + "; }\n");
     }
 {
-std::string destroy = "    private _destroy: (inout this) = {\n";
+std::string destroy{"    private _destroy: (inout this) = {\n"};
 
     //  Add destroy
 
@@ -1824,7 +1824,7 @@ std::string destroy = "    private _destroy: (inout this) = {\n";
     //  Add default constructor
     CPP2_UFCS(add_member)(t, "    operator=: (out this) = { }");
 {
-std::string value_set = "";
+std::string value_set{""};
 
     //  Add copy/move construction and assignment
 

source/to_cpp1.h

@@ -56,7 +56,7 @@ auto pad(int padding)
     };
 }
 
-auto multi_return_type_name(declaration_node const& n) 
+auto multi_return_type_name(declaration_node const& n)
     -> std::string
 {
     //  When generating a multi-return struct, also enable multi-return
@@ -1326,7 +1326,7 @@ class cppfront
                 printer.print_extra(
                     "\n// Generated by cppfront "
                     #include "version.info"
-                    " build " 
+                    " build "
                     #include "build.info"
                 );
             }
@@ -4083,7 +4083,7 @@ class cppfront
             printer.print_extra( "{");
             for (auto& param : n.parameters->parameters) {
                 printer.print_extra( "\n");
-                printer.print_extra( print_to_string(*param) );
+                printer.print_extra( print_to_string(*param, false, false, true) );
             }
         }
 
@@ -4170,7 +4170,8 @@ class cppfront
     auto emit(
         parameter_declaration_node const& n,
         bool                              is_returns            = false,
-        bool                              is_template_parameter = false
+        bool                              is_template_parameter = false,
+        bool                              is_statement          = false
     )
         -> void
     {   STACKINSTR
@@ -4492,8 +4493,16 @@ class cppfront
             )
         {
             auto guard = stack_element(current_declarations, &*n.declaration);
-            printer.print_cpp2( " = ", n.declaration->initializer->position() );
-            emit(*n.declaration->initializer);
+            if (is_statement) {
+                printer.print_cpp2( "{", n.declaration->initializer->position() );
+            }
+            else {
+                printer.print_cpp2( " = ", n.declaration->initializer->position() );
+            }
+            emit(*n.declaration->initializer, !is_statement);
+            if (is_statement) {
+                printer.print_cpp2( "};", n.declaration->initializer->position() );
+            }
         }
     }
 
@@ -4679,7 +4688,7 @@ class cppfront
             );
         }
         else {
-            emit(*n.parameters, false, false, generating_postfix_inc_dec); 
+            emit(*n.parameters, false, false, generating_postfix_inc_dec);
         }
 
         //  For an anonymous function, the emitted lambda is 'constexpr' or 'mutable'
@@ -5511,6 +5520,22 @@ class cppfront
                         type = print_to_string(*a->type_id);
                     }
 
+                    auto print_initializer_to_string = [&](expression_node const& n) -> std::string {
+                        //  If this expression is just a single expression-list, we can
+                        //  take over direct control of emitting it without needing to
+                        //  go through the whole grammar, and surround it with braces
+                        if (n.is_expression_list()) {
+                            return "{ "
+                                   + print_to_string(*n.get_expression_list(), false)
+                                   + " }";
+                        }
+                        //  Otherwise, just emit the general expression as usual
+                        else {
+                            return " = "
+                                   + print_to_string(n);
+                        }
+                    };
+
                     //  (*) If this is at type scope, Cpp1 requires an out-of-line declaration dance
                     //  for some cases to work - see https://stackoverflow.com/questions/11928089/
                     if (n.parent_is_type())
@@ -5542,8 +5567,7 @@ class cppfront
                                     + " "
                                     + type_qualification_if_any_for(n)
                                     + print_to_string(*n.identifier)
-                                    + " = "
-                                    + print_to_string( *std::get<alias_node::an_object>(a->initializer) )
+                                    + print_initializer_to_string( *std::get<alias_node::an_object>(a->initializer) )
                                     + ";\n",
                                 n.position()
                             );
@@ -5564,8 +5588,7 @@ class cppfront
                             type + " "
                                 + intro + " "
                                 + print_to_string(*n.identifier)
-                                + " = "
-                                + print_to_string( *std::get<alias_node::an_object>(a->initializer) )
+                                + print_initializer_to_string( *std::get<alias_node::an_object>(a->initializer) )
                                 + ";\n",
                             n.position()
                         );