Devel::callparser provides a c api, for xs modules, concerned with custom parsing. it is centred around the function cv_set_call_parser, which allows xs code to attach a magical annotation to a perl subroutine, resulting in resolvable calls to that subroutine having their arguments parsed by arbitrary c code. (this is a more conveniently structured facility than the core's pl_keyword_plugin api.) this module makes cv_set_call_parser and several supporting functions available.