Use LAZY mode for files

Author: d-frey

include/tao/json/sax/parse_file.hpp

@@ -4,6 +4,8 @@
 #ifndef TAOCPP_JSON_INCLUDE_SAX_PARSE_FILE_HPP
 #define TAOCPP_JSON_INCLUDE_SAX_PARSE_FILE_HPP
 
+#include <utility>
+
 #include "../internal/action.hpp"
 #include "../internal/control.hpp"
 #include "../internal/grammar.hpp"
@@ -17,11 +19,11 @@ namespace tao
       namespace sax
       {
          // SAX producer to parse a file containing a JSON string representation
-         template< typename Consumer >
-         void parse_file( const std::string& filename, Consumer& consumer )
+         template< typename T, typename Consumer >
+         void parse_file( T&& filename, Consumer& consumer )
          {
-            json_pegtl::file_input<> input( filename );
-            json_pegtl::parse< internal::grammar, internal::action, internal::control >( input, consumer );
+            json_pegtl::file_input< json_pegtl::tracking_mode::LAZY > in( std::forward< T >( filename ) );
+            json_pegtl::parse< internal::grammar, internal::action, internal::control >( in, consumer );
          }
 
       }  // sax