Replace Byte pointer with a generic pointer type

boot/semantic.cc

@@ -180,6 +180,8 @@ namespace elna::boot
                 build_procedure(definition->heading()), definition->parameter_names);
 
         this->symbols->enter(definition->identifier.identifier, info);
+        this->symbols = std::make_shared<symbol_table>(this->symbols);
+
         if (definition->body.has_value())
         {
             for (constant_definition *const constant : definition->body.value().constants())
@@ -195,6 +197,7 @@ namespace elna::boot
                 statement->accept(this);
             }
         }
+        this->symbols = this->symbols->scope();
     }
 
     void declaration_visitor::visit(assign_statement *statement)