That cool! Thank you! -----原始邮件----- From: Nathan Ridge Sent: Tuesday, November 08, 2011 10:42 AM Newsgroups: gmane.comp.lib.boost.user To: Boost Mailing List Subject: Re: [variant] a question about recursive typedef

Hello, everyone:

I want write a general linked list(any element in the list may be a node or nested general linked list, so recursive). I think general linked list could by defined as following(see spirit's tutorial mini_xml):

glist = *glist_node glist_node = node | glist

so here is the typedef according to the above rules:

struct node { int data; }; typedef boost::variant glist_node; //typedef 1 typedef std::list glist; //typedef 2

so the problem comes here, in the typedef 1, how can I forward declare glist?

I think this should work: struct node { int data; }; typedef boost::make_recursive_variantboost::recursive_variant_ >::type glist_node; typedef std::list glist; Regards, Nate =