Added initial support for const qualifier

Author: hsutter

cpp2util.h

@@ -196,33 +196,33 @@ class out {
     #define CPP2_SOURCE_LOCATION_PARAM              , std::source_location where
     #define CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT , std::source_location where = std::source_location::current()
     #define CPP2_SOURCE_LOCATION_PARAM_SOLO         std::source_location where
-    //#define CPP2_SOURCE_LOCATION_PARAM_SOLO_ANON    std::source_location
     #define CPP2_SOURCE_LOCATION_ARG                , where
-    //#define CPP2_SOURCE_LOCATION_ARG_SOLO           where
 #else
     #define CPP2_SOURCE_LOCATION_PARAM
     #define CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT
     #define CPP2_SOURCE_LOCATION_PARAM_SOLO
-    //#define CPP2_SOURCE_LOCATION_PARAM_SOLO_ANON
     #define CPP2_SOURCE_LOCATION_ARG
-    //#define CPP2_SOURCE_LOCATION_ARG_SOLO
 #endif
 
+//  For C++23: make this std::string_view and drop the macro
+//      Before C++23 std::string_view was not guaranteed to be trivially copyable,
+//      and so in<T> will pass it by const& and really it should be by value
+#define CPP2_MESSAGE_PARAM  char const*
 
 class contract_group {
 public:
-    using handler = void (*)(const char* msg CPP2_SOURCE_LOCATION_PARAM) noexcept;
+    using handler = void (*)(CPP2_MESSAGE_PARAM msg CPP2_SOURCE_LOCATION_PARAM) noexcept;
 
     constexpr contract_group  (handler h = nullptr)  : reporter(h) { }
     constexpr auto set_handler(handler h) -> handler { assert(h); auto old = reporter; reporter = h; return old; }
     constexpr auto get_handler() const    -> handler { return reporter; }
-    constexpr auto expects    (bool b, const char* msg = "" CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT)
+    constexpr auto expects    (bool b, CPP2_MESSAGE_PARAM msg = "" CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT)
                                           -> void { if (!b) reporter(msg CPP2_SOURCE_LOCATION_ARG); }
 private:
     handler reporter;
 };
 
-[[noreturn]] auto report_and_terminate(std::string_view group, const char* msg = "" CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT) noexcept -> void {
+[[noreturn]] auto report_and_terminate(std::string_view group, CPP2_MESSAGE_PARAM msg = "" CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT) noexcept -> void {
     std::cerr
 #ifdef CPP2_USE_SOURCE_LOCATION
         << where.file_name() << "2("
@@ -238,27 +238,27 @@ class contract_group {
 }
 
 auto inline Default = contract_group( 
-    [](const char* msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
+    [](CPP2_MESSAGE_PARAM msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
         report_and_terminate("Contract",      msg CPP2_SOURCE_LOCATION_ARG);
     }
 );
 auto inline Bounds  = contract_group( 
-    [](const char* msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
+    [](CPP2_MESSAGE_PARAM msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
         report_and_terminate("Bounds safety", msg CPP2_SOURCE_LOCATION_ARG);
     } 
 );
 auto inline Null    = contract_group( 
-    [](const char* msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
+    [](CPP2_MESSAGE_PARAM msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
         report_and_terminate("Null safety",   msg CPP2_SOURCE_LOCATION_ARG);
     } 
 );
 auto inline Type    = contract_group( 
-    [](const char* msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
+    [](CPP2_MESSAGE_PARAM msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
         report_and_terminate("Type safety",   msg CPP2_SOURCE_LOCATION_ARG);
     } 
 );
 auto inline Testing = contract_group( 
-    [](const char* msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
+    [](CPP2_MESSAGE_PARAM msg CPP2_SOURCE_LOCATION_PARAM)noexcept { 
         report_and_terminate("Testing",       msg CPP2_SOURCE_LOCATION_ARG);
     } 
 );

cppfront.cpp

@@ -845,6 +845,11 @@ class cppfront
         assert(n.identifier);
         emit(*n.identifier);
 
+        if (n.const_qualifier) {
+            printer.print_cpp2(" ", n.const_qualifier->position());
+            emit(*n.const_qualifier);
+        }
+
         if (!n.template_args.empty()) {
             printer.print_cpp2("<", n.open_angle);
             auto first = true;
@@ -1559,6 +1564,10 @@ class cppfront
         }
         else {
             emit( id_expr );
+            if (n.declaration->pointer_declarator) {
+                printer.print_cpp2(" ", n.declaration->pointer_declarator->position());
+                emit(*n.declaration->pointer_declarator);
+            }
         }
 
         //  Then any suffix
@@ -1682,8 +1691,12 @@ class cppfront
         assert(n.condition);
         emit (*n.condition);
         printer.print_cpp2(", ", n.position());
-        assert (n.message);
-        emit (*n.message);
+        if (n.message) {
+            emit (*n.message);
+        }
+        else {
+            printer.print_cpp2("\"\"", n.position());
+        }
         printer.print_cpp2(");", n.position());
     }
 
@@ -1861,7 +1874,7 @@ class cppfront
             function_returns.pop_back();
         }
 
-        //  Object with initializer
+        //  Object with optional initializer
         else if (!printer.doing_declarations_only() && n.is(declaration_node::object))
         {
             auto& type = std::get<declaration_node::object>(n.type);

parse.h

@@ -332,7 +332,8 @@ auto prefix_expression_node::visit(auto& v, int depth) -> void
 
 struct unqualified_id_node
 {
-    token const* identifier;
+    token const* const_qualifier = {};  // optional
+    token const* identifier      = {};  // required
 
     enum active { empty=0, expression, id_expression };
 
@@ -349,11 +350,6 @@ struct unqualified_id_node
     };
     std::vector<term> template_args;
 
-    unqualified_id_node( token const* tok) 
-        : identifier{ tok }
-    {
-    }
-
     auto position() const -> source_position
     {
         assert (identifier);
@@ -363,6 +359,9 @@ struct unqualified_id_node
     auto visit(auto& v, int depth) -> void
     {
         v.start(*this, depth);
+        if (const_qualifier) {
+            v.start(*const_qualifier, depth+1);
+        }
         assert (identifier);
         v.start(*identifier, depth+1);
 
@@ -1481,8 +1480,8 @@ class parser
 
 
     //G unqualified-id:
-    //G     identifier
-    //G     template-id
+    //G     const-opt identifier
+    //G     const-opt template-id
     //GT     operator-function-id
     //G
     //G template-id:
@@ -1499,11 +1498,19 @@ class parser
     {
         //  Handle the identifier
         if (curr().type() != lexeme::Identifier &&
-            curr().type() != lexeme::Keyword)   // because of fundamental types like 'int' which are keywords
+            curr().type() != lexeme::Keyword)   // 'const', and fundamental types that are keywords
         {
             return {};
         }
-        auto n = std::make_unique<unqualified_id_node>( &curr() );
+
+        auto n = std::make_unique<unqualified_id_node>();
+
+        if (curr().type() == lexeme::Keyword && curr() == "const") {
+            n->const_qualifier = &curr();
+            next();
+        }
+
+        n->identifier =  &curr();
         next();
 
         //  Handle the template-argument-list if there is one