From 7d07bef760a8807fe49fbe5c90799a1822f95973 Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Thu, 8 Oct 2026 19:45:19 +0200
Subject: Make modules re-exportable

---
 boot/ast.cc        |  5 +++--
 boot/dependency.cc |  2 +-
 boot/parser.yy     | 20 +++++++++++++++-----
 boot/symbol.cc     | 17 +++++++++++++++--
 4 files changed, 34 insertions(+), 10 deletions(-)

(limited to 'boot')

diff --git a/boot/ast.cc b/boot/ast.cc
index 69b15d3..456797a 100644
--- a/boot/ast.cc
+++ b/boot/ast.cc
@@ -1681,8 +1681,9 @@ namespace elna::boot
         delete this->alternative;
     }
 
-    import_declaration::import_declaration(const source_position position, std::vector<std::string>&& segments)
-        : node(position), segments(std::move(segments))
+    import_declaration::import_declaration(const source_position position, std::vector<std::string>&& segments,
+            const bool exported)
+        : node(position), segments(std::move(segments)), exported(exported)
     {
     }
 
diff --git a/boot/dependency.cc b/boot/dependency.cc
index 5053a36..31eccc9 100644
--- a/boot/dependency.cc
+++ b/boot/dependency.cc
@@ -90,7 +90,7 @@ namespace elna::boot
         }
         for (const auto& import : imports)
         {
-            const std::vector<import_collision> collisions = result.value.add_import(import.symbols);
+            const std::vector<import_collision> collisions = result.value.add_import(import.symbols, import.reexport);
 
             for (const import_collision& collision : collisions)
             {
diff --git a/boot/parser.yy b/boot/parser.yy
index cfa63d5..65d3dba 100644
--- a/boot/parser.yy
+++ b/boot/parser.yy
@@ -160,7 +160,8 @@ along with GCC; see the file COPYING3.  If not see
 %type <std::vector<elna::boot::identifier_definition>> identifier_definitions;
 %type <std::unique_ptr<elna::boot::attribute>> attribute;
 %type <std::vector<elna::boot::attribute>> attributes;
-%type <std::vector<std::string>> import_declaration;
+%type <std::pair<std::vector<std::string>, bool>> import_declaration;
+%type <std::vector<std::string>> import_path;
 %type <std::vector<elna::boot::identifier>> required_identifiers optional_identifiers generic_parameters;
 %type <std::unique_ptr<elna::boot::enumeration_type_expression::member_declaration>> enumeration_member;
 %type <std::vector<elna::boot::enumeration_type_expression::member_declaration>> enumeration_members;
@@ -736,22 +737,31 @@ variable_declarations:
             $$ = $2;
             $$.insert(std::cbegin($$), $1);
         }
-import_declaration:
-    IDENTIFIER "." import_declaration
+import_path:
+    IDENTIFIER "." import_path
         {
             $$ = $3;
             $$.emplace($$.cbegin(), $1);
         }
     | IDENTIFIER { $$.emplace_back($1); }
+import_declaration:
+    import_path "*" { $$ = { $1, true }; }
+    | import_path { $$ = { $1, false }; }
 import_declarations:
     import_declaration "," import_declarations
         {
+            auto [segments, exported] = $1;
+
             $$ = $3;
-            $$.emplace($$.cbegin(), new boot::import_declaration(boot::make_position(@$), $1));
+            $$.emplace($$.cbegin(),
+                    new boot::import_declaration(boot::make_position(@$), std::move(segments), exported));
         }
     | import_declaration
         {
-            $$.emplace_back(new boot::import_declaration(boot::make_position(@$), $1));
+            auto [segments, exported] = $1;
+
+            $$.emplace_back(
+                    new boot::import_declaration(boot::make_position(@$), std::move(segments), exported));
         }
 type_declaration:
     identifier_definition generic_parameters "=" type_expression
diff --git a/boot/symbol.cc b/boot/symbol.cc
index 375cbfd..2805839 100644
--- a/boot/symbol.cc
+++ b/boot/symbol.cc
@@ -522,7 +522,8 @@ namespace elna::boot
         return this->unresolved.insert({ symbol_name, std::move(forward_declaration) }).second;
     }
 
-    std::vector<import_collision> symbol_bag::add_import(const std::shared_ptr<symbol_table>& symbols)
+    std::vector<import_collision> symbol_bag::add_import(const std::shared_ptr<symbol_table>& symbols,
+            const bool reexport)
     {
         std::vector<import_collision> collisions;
 
@@ -538,7 +539,10 @@ namespace elna::boot
             }
         }
         this->imports.push_back(symbols);
-
+        if (reexport)
+        {
+            this->reexports.push_back(symbols);
+        }
         return collisions;
     }
 
@@ -553,6 +557,15 @@ namespace elna::boot
         if (!m_exported)
         {
             m_exported = std::make_shared<symbol_table>(symbols->scope());
+            // The same symbol can reach a module along several re-export
+            // paths; it is the same info then, so entering it twice is a no-op.
+            for (const auto& reexported : this->reexports)
+            {
+                for (const auto& [name, info] : *reexported)
+                {
+                    m_exported->enter(name, info);
+                }
+            }
             for (const auto& [name, info] : *symbols)
             {
                 if (info->exported)
-- 
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