Add preprocessor

The parser now parses macros and inclusion directives.

include/cppast/libclang_parser.hpp

@@ -9,12 +9,31 @@
 
 namespace cppast
 {
+    class libclang_compile_config;
+
+    namespace detail
+    {
+        struct libclang_compile_config_access
+        {
+            static const std::string& clang_binary(const libclang_compile_config& config);
+
+            static const std::vector<std::string>& flags(const libclang_compile_config& config);
+        };
+    } // namespace detail
+
     /// Compilation config for the [cppast::libclang_parser]().
     class libclang_compile_config final : public compile_config
     {
     public:
         libclang_compile_config();
 
+        /// \effects Sets the path to the location of the `clang++` binary.
+        /// \notes It will be used for preprocessing.
+        void set_clang_binary(std::string binary)
+        {
+            clang_binary_ = std::move(binary);
+        }
+
     private:
         void do_set_flags(cpp_standard standard, type_safe::flag_set<compile_flag> flags) override;
 
@@ -23,6 +42,15 @@ namespace cppast
         void do_add_macro_definition(std::string name, std::string definition) override;
 
         void do_remove_macro_definition(std::string name) override;
+
+        const char* do_get_name() const noexcept override
+        {
+            return "libclang";
+        }
+
+        std::string clang_binary_;
+
+        friend detail::libclang_compile_config_access;
     };
 
     /// A parser that uses libclang.
@@ -33,7 +61,7 @@ namespace cppast
         ~libclang_parser() noexcept override;
 
     private:
-        std::unique_ptr<cpp_file> do_parse(const cpp_entity_index& idx, const std::string& path,
+        std::unique_ptr<cpp_file> do_parse(const cpp_entity_index& idx, std::string path,
                                            const compile_config& config) const override;
 
         struct impl;