Function mpc::glue::parse

pub fn parse(
    filename: *const c_char, 
    string: *const c_char, 
    p: *mut mpc_parser_t
) -> Result<*mut mpc_ast_t, *mut mpc_err_t>

Convert parse_result to Result<*mut mpc_ast_t, *mut mpc_err_t>. It is more idiomatic