Extract common main function of examples

example/CMakeLists.txt

@@ -3,7 +3,7 @@
 # found in the top-level directory of this distribution.
 
 function(_cppast_example name)
-    add_executable(cppast_example_${name} ${name}.cpp)
+    add_executable(cppast_example_${name} ${name}.cpp example_parser.hpp)
     target_link_libraries(cppast_example_${name} PUBLIC cppast)
 endfunction()
 

example/ast_printer.cpp

@@ -5,61 +5,31 @@
 /// \file
 /// This is a very primitive version of the cppast tool.
 
-#include <iostream>
+#include <cppast/visitor.hpp> // visit()
 
-#include <cppast/libclang_parser.hpp> // libclang_compilation_database, libclang_parser, etc.
+#include "example_parser.hpp"
-#include <cppast/visitor.hpp>         // visit()
+
+void print_ast(const cppast::cpp_file& file)
+{
+    std::string prefix;
+    // visit each entity in the file
+    cppast::visit(file, [&](const cppast::cpp_entity& e, cppast::visitor_info info) {
+        if (info.event == cppast::visitor_info::container_entity_exit) // exiting an old container
+            prefix.pop_back();
+        else if (info.event == cppast::visitor_info::container_entity_enter)
+        // entering a new container
+        {
+            std::cout << prefix << "'" << e.name() << "' - " << cppast::to_string(e.kind()) << '\n';
+            prefix += "\t";
+        }
+        else // if (info.event == cppast::visitor_info::leaf_entity) // a non-container entity
+            std::cout << prefix << "'" << e.name() << "' - " << cppast::to_string(e.kind()) << '\n';
+
+        return true; // continue with visit
+    });
+}
 
 int main(int argc, char* argv[])
 {
-    if (argc != 2)
+    return example_main(argc, argv, {}, &print_ast);
-    {
-        std::cerr << "usage: " << argv[0] << " <compile-commands-json-dir>\n";
-        return 1;
-    }
-    else
-    {
-        cppast::libclang_compilation_database database(argv[1]); // the compilation database
-        cppast::cpp_entity_index              index; // only needed for cross referencing in the AST
-
-        // simple_file_parser allows parsing multiple files and stores the results for us
-        cppast::simple_file_parser<cppast::libclang_parser> parser(type_safe::ref(index));
-        try
-        {
-            cppast::parse_database(parser, database); // parse all files in the database
-        }
-        catch (cppast::libclang_error& ex)
-        {
-            std::cerr << "fatal libclang error: " << ex.what() << '\n';
-            return 1;
-        }
-
-        if (parser.error())
-            // a non-fatal parse error
-            // error has been logged to stderr
-            return 1;
-
-        for (auto& file : parser.files()) // for each file in the project
-        {
-            std::string prefix;
-            // visit each entity in the file
-            cppast::visit(file, [&](const cppast::cpp_entity& e, cppast::visitor_info info) {
-                if (info.event
-                    == cppast::visitor_info::container_entity_exit) // exiting an old container
-                    prefix.pop_back();
-                else if (info.event == cppast::visitor_info::container_entity_enter)
-                // entering a new container
-                {
-                    std::cout << prefix << "'" << e.name() << "' - " << cppast::to_string(e.kind())
-                              << '\n';
-                    prefix += "\t";
-                }
-                else // if (info.event == cppast::visitor_info::leaf_entity) // a non-container entity
-                    std::cout << prefix << "'" << e.name() << "' - " << cppast::to_string(e.kind())
-                              << '\n';
-
-                return true; // continue with visit
-            });
-        }
-    }
 }

example/example_parser.hpp

@@ -0,0 +1,51 @@
+// Copyright (C) 2017 Jonathan Müller <jonathanmueller.dev@gmail.com>
+// This file is subject to the license terms in the LICENSE file
+// found in the top-level directory of this distribution.
+
+#ifndef CPPAST_EXAMPLE_PARSER_HPP_INCLUDED
+#define CPPAST_EXAMPLE_PARSER_HPP_INCLUDED
+
+#include <iostream>
+
+#include <cppast/libclang_parser.hpp>
+
+// reads the database directory from the command line argument
+// parses all files in that directory
+// and invokes the callback for each of them
+template <typename Callback>
+int example_main(int argc, char* argv[], const cppast::cpp_entity_index& index, Callback cb)
+{
+    if (argc != 2)
+    {
+        std::cerr << "usage: " << argv[0] << " <compile-commands-json-dir>\n";
+        return 1;
+    }
+    else
+    {
+        cppast::libclang_compilation_database database(argv[1]); // the compilation database
+
+        // simple_file_parser allows parsing multiple files and stores the results for us
+        cppast::simple_file_parser<cppast::libclang_parser> parser(type_safe::ref(index));
+        try
+        {
+            cppast::parse_database(parser, database); // parse all files in the database
+        }
+        catch (cppast::libclang_error& ex)
+        {
+            std::cerr << "fatal libclang error: " << ex.what() << '\n';
+            return 1;
+        }
+
+        if (parser.error())
+            // a non-fatal parse error
+            // error has been logged to stderr
+            return 1;
+
+        for (auto& file : parser.files())
+            cb(file);
+    }
+
+    return 0;
+}
+
+#endif // CPPAST_EXAMPLE_PARSER_HPP_INCLUDED