feat: allow exporting declarations

JohelEGP · JohelEGP · commit 9221682c0b6f · 2023-08-03T00:08:11.000-04:00
diff --git a/source/cppfront.cpp b/source/cppfront.cpp
@@ -197,7 +197,7 @@ class positional_printer
     std::vector<comment> const* pcomments       = {}; // Cpp2 comments data
     source const*               psource         = {};
     parser const*               pparser         = {};
-                                                
+
     source_position curr_pos                    = {}; // current (line,col) in output
     lineno_t        generated_pos_line          = {}; // current line in generated output
     int             last_line_indentation       = {};
@@ -1226,7 +1226,7 @@ class cppfront
 
         //---------------------------------------------------------------------
         //  Do lowered file prolog
-        // 
+        //
         //  Only emit extra lines if we actually have Cpp2, because
         //  we want pure-Cpp1 files to pass through with zero changes
         if (source.has_cpp2())
@@ -1284,7 +1284,7 @@ class cppfront
             }
         }
 
-        
+
         //---------------------------------------------------------------------
         //  Do phase1_type_defs_func_decls
         //
@@ -1641,7 +1641,7 @@ class cppfront
         {
             add_move = false;
         }
-    
+
         if (
             emitting_move_that_function
             && *n.identifier == "that"
@@ -2253,7 +2253,7 @@ class cppfront
                     return;
                 } else if (
                     is_literal(tok->type()) || n.expression->expr->is_result_a_temporary_variable()
-                ) 
+                )
                 {
                     errors.emplace_back(
                         n.position(),
@@ -2545,7 +2545,7 @@ class cppfront
     )
         -> bool
     {
-        if (!fun_node) { 
+        if (!fun_node) {
             return false;
         }
         if (addr_cnt > deref_cnt) {
@@ -2572,11 +2572,11 @@ class cppfront
     )
         -> bool
     {
-        if (!type_id_node) { 
+        if (!type_id_node) {
             return false;
         }
         if (addr_cnt > deref_cnt) {
-            return true; 
+            return true;
         }
 
         if ( type_id_node->dereference_of ) {
@@ -2753,7 +2753,7 @@ class cppfront
             {
                 auto& unqual = std::get<id_expression_node::unqualified>(id->id);
                 assert(unqual);
-                //  TODO: Generalize this: 
+                //  TODO: Generalize this:
                 //        - we don't recognize pointer types from Cpp1
                 //        - we don't deduce pointer types from parameter_declaration_list_node
                 if ( is_pointer_declaration(unqual->identifier) ) {
@@ -4817,7 +4817,7 @@ class cppfront
         }
 
         //  If this is a generated declaration (negative source line number),
-        //  add a line break before 
+        //  add a line break before
         if (
             printer.get_phase() == printer.phase2_func_defs
             && n.position().lineno < 1
@@ -4860,6 +4860,8 @@ class cppfront
                     else {
                         printer.print_cpp2("public: ", n.position());
                     }
+                } else if (n.is_export()) {
+                    printer.print_cpp2(to_string(n.access) + " ", n.position());
                 }
 
                 //  Emit template parameters if any
@@ -5014,11 +5016,32 @@ class cppfront
             }
         }
 
+        //  Emit export on forward declaration.
+        if (
+            n.is_export()
+            && n.parent_is_namespace()
+           )
+        {
+            if (
+                printer.get_phase() == printer.phase0_type_decls
+                || (
+                    printer.get_phase() == printer.phase1_type_defs_func_decls
+                    && !n.is_type() // Done in phase 0.
+                    )
+                )
+            {
+                printer.print_cpp2(to_string(n.access) + " ", n.position());
+            }
+        }
         //  In class definitions, emit the explicit access specifier if there
         //  is one, or default to private for data and public for functions
-        if (printer.get_phase() == printer.phase1_type_defs_func_decls)
+        else if (printer.get_phase() == printer.phase1_type_defs_func_decls)
         {
-            if (!n.is_default_access()) {
+            if (
+                !n.is_default_access()
+                && !n.is_export()
+               )
+            {
                 assert (is_in_type);
                 printer.print_cpp2(to_string(n.access) + ": ", n.position());
             }
@@ -5453,7 +5476,7 @@ class cppfront
                             //  A2) This is '(out   this, move that)'
                             //      and no  '(inout this, move that)' was written by the user
                             //  (*) and no  '(inout this,      that)' was written by the user (*)
-                            //  
+                            //
                             //  (*) This third test is to tie-break M2 and A2 in favor of M2. Both M2 and A2
                             //      can generate a missing '(inout this, move that)', and if we have both
                             //      options then we should prefer to use M2 (generate move assignment from
diff --git a/source/parse.h b/source/parse.h
@@ -721,7 +721,7 @@ struct postfix_expression_node
         if (ops.empty()) {
             return false;
         } else {
-            return (ops.front().op->type() == lexeme::Ampersand 
+            return (ops.front().op->type() == lexeme::Ampersand
                     || ops.front().op->type() == lexeme::Tilde);
         }
     }
@@ -2225,7 +2225,7 @@ struct alias_node
 };
 
 
-enum class accessibility { default_ = 0, public_, protected_, private_ };
+enum class accessibility { default_ = 0, public_, protected_, private_, export_ };
 
 auto to_string(accessibility a)
     -> std::string
@@ -2234,6 +2234,7 @@ auto to_string(accessibility a)
     break;case accessibility::public_   : return "public";
     break;case accessibility::protected_: return "protected";
     break;case accessibility::private_  : return "private";
+    break;case accessibility::export_  : return "export";
     break;default: assert(a == accessibility::default_);
     }
     return "default";
@@ -2358,6 +2359,12 @@ struct declaration_node
         return access == accessibility::private_;
     }
 
+    auto is_export() const
+        -> bool
+    {
+        return access == accessibility::export_;
+    }
+
     auto is_default_access() const
         -> bool
     {
@@ -3993,7 +4000,7 @@ class parser
             //      || curr().type() == lexeme::LeftBrace
             )
         {
-            bool inside_initializer = ( 
+            bool inside_initializer = (
                 peek(-1) && peek(-1)->type() == lexeme::Assignment
             );
             auto open_paren = &curr();
@@ -4015,12 +4022,12 @@ class parser
             next();
             if (
                    curr().type() != lexeme::Semicolon
-                && curr().type() != lexeme::RightParen 
-                && curr().type() != lexeme::RightBracket 
+                && curr().type() != lexeme::RightParen
+                && curr().type() != lexeme::RightBracket
                 && curr().type() != lexeme::Comma
             ) {
                 expr_list->inside_initializer = false;
-            } 
+            }
             n->expr = std::move(expr_list);
             return n;
         }
@@ -4374,7 +4381,7 @@ class parser
     //G     shift-expression '<<' additive-expression
     //G     shift-expression '>>' additive-expression
     //G
-    auto shift_expression(bool allow_angle_operators = true) 
+    auto shift_expression(bool allow_angle_operators = true)
         -> auto
     {
         if (allow_angle_operators) {
@@ -4409,7 +4416,7 @@ class parser
     //G     shift-expression
     //G     compare-expression '<=>' shift-expression
     //G
-    auto compare_expression(bool allow_angle_operators = true) 
+    auto compare_expression(bool allow_angle_operators = true)
         -> auto
     {
         return binary_expression<compare_expression_node> (
@@ -4425,7 +4432,7 @@ class parser
     //G     relational-expression '<=' compare-expression
     //G     relational-expression '>=' compare-expression
     //G
-    auto relational_expression(bool allow_angle_operators = true) 
+    auto relational_expression(bool allow_angle_operators = true)
         -> auto
     {
         if (allow_angle_operators) {
@@ -4457,7 +4464,7 @@ class parser
     //G     equality-expression '==' relational-expression
     //G     equality-expression '!=' relational-expression
     //G
-    auto equality_expression(bool allow_angle_operators = true) 
+    auto equality_expression(bool allow_angle_operators = true)
         -> auto
     {
         return binary_expression<equality_expression_node> (
@@ -4470,7 +4477,7 @@ class parser
     //G     equality-expression
     //G     bit-and-expression '&' equality-expression
     //G
-    auto bit_and_expression(bool allow_angle_operators = true) 
+    auto bit_and_expression(bool allow_angle_operators = true)
         -> auto
     {
         return binary_expression<bit_and_expression_node> (
@@ -4483,7 +4490,7 @@ class parser
     //G     bit-and-expression
     //G     bit-xor-expression '^' bit-and-expression
     //G
-    auto bit_xor_expression(bool allow_angle_operators = true) 
+    auto bit_xor_expression(bool allow_angle_operators = true)
         -> auto
     {
         return binary_expression<bit_xor_expression_node> (
@@ -4496,7 +4503,7 @@ class parser
     //G     bit-xor-expression
     //G     bit-or-expression '|' bit-xor-expression
     //G
-    auto bit_or_expression(bool allow_angle_operators = true) 
+    auto bit_or_expression(bool allow_angle_operators = true)
         -> auto
     {
         return binary_expression<bit_or_expression_node> (
@@ -4509,7 +4516,7 @@ class parser
     //G     bit-or-expression
     //G     logical-and-expression '&&' bit-or-expression
     //G
-    auto logical_and_expression(bool allow_angle_operators = true) 
+    auto logical_and_expression(bool allow_angle_operators = true)
         -> auto
     {
         return binary_expression<logical_and_expression_node> (
@@ -4524,7 +4531,7 @@ class parser
     //G     logical-and-expression
     //G     logical-or-expression '||' logical-and-expression
     //G
-    auto logical_or_expression(bool allow_angle_operators = true) 
+    auto logical_or_expression(bool allow_angle_operators = true)
         -> auto
     {
         return binary_expression<logical_or_expression_node> (
@@ -4842,7 +4849,7 @@ class parser
 
             n->open_angle = curr().position();
             next();
-            
+
             auto term = unqualified_id_node::term{};
 
             do {
@@ -6413,7 +6420,7 @@ class parser
             }
             assert (n->is_type());
         }
-        
+
         //  Or a function type, declaring a function - and tell the function whether it's in a user-defined type
         else if (auto t = function_type(n.get(), named))
         {
@@ -6561,11 +6568,11 @@ class parser
                 )
             {
                 auto& type = std::get<declaration_node::an_object>(n->type);
-                // object initialized by the address of the curr() object 
+                // object initialized by the address of the curr() object
                 if (peek(1)->type() == lexeme::Ampersand) {
                     type->address_of = &curr();
                 }
-                // object initialized by (potentially multiple) dereference of the curr() object 
+                // object initialized by (potentially multiple) dereference of the curr() object
                 else if (peek(1)->type() == lexeme::Multiply) {
                     type->dereference_of = &curr();
                     for (int i = 1; peek(i)->type() == lexeme::Multiply; ++i)
@@ -6770,7 +6777,7 @@ class parser
                 return {};
             }
             if (
-                t->is_wildcard() 
+                t->is_wildcard()
                 || ( t->get_token() && t->get_token()->to_string(true) == "auto" )
             ) {
                 errors.emplace_back(
@@ -6878,6 +6885,10 @@ class parser
                 access = accessibility::private_;
                 next();
             }
+            else if (curr() == "export") {
+                access = accessibility::export_;
+                next();
+            }
 
             //  If they wrote an access-specifier, see if they put a ':'
             //  after it out of Cpp1 habit (there's no colon in Cpp2)
diff --git a/source/sema.h b/source/sema.h
@@ -1216,7 +1216,19 @@ class sema
         }
 
         if (
-            n.access != accessibility::default_
+            n.is_export()
+            && !n.parent_is_namespace()
+            )
+        {
+            errors.emplace_back(
+                n.position(),
+                "an export declaration is only allowed at namespace scope"
+            );
+            return false;
+        }
+        else if (
+            !n.is_export()
+            && !n.is_default_access()
             && !n.parent_is_type()
             )
         {
@@ -1564,7 +1576,7 @@ class sema
             //  Skip type scope (member) variables
             && !(n.parent_is_type() && n.is_object())
             //  Skip unnamed variables
-            && n.identifier 
+            && n.identifier
             //  Skip non-out parameters
             && (
                 !inside_parameter_list
