{"action":"opened","issue":{"url":"https://api.github.com/repos/solodon4/Mach7/issues/50","repository_url":"https://api.github.com/repos/solodon4/Mach7","labels_url":"https://api.github.com/repos/solodon4/Mach7/issues/50/labels{/name}","comments_url":"https://api.github.com/repos/solodon4/Mach7/issues/50/comments","events_url":"https://api.github.com/repos/solodon4/Mach7/issues/50/events","html_url":"https://github.com/solodon4/Mach7/issues/50","id":138466707,"number":50,"title":"[question] Clarify how users should define XTL sub-type relation for their types","user":{"login":"akrzemi1","id":2912717,"avatar_url":"https://avatars.githubusercontent.com/u/2912717?v=3","gravatar_id":"","url":"https://api.github.com/users/akrzemi1","html_url":"https://github.com/akrzemi1","followers_url":"https://api.github.com/users/akrzemi1/followers","following_url":"https://api.github.com/users/akrzemi1/following{/other_user}","gists_url":"https://api.github.com/users/akrzemi1/gists{/gist_id}","starred_url":"https://api.github.com/users/akrzemi1/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/akrzemi1/subscriptions","organizations_url":"https://api.github.com/users/akrzemi1/orgs","repos_url":"https://api.github.com/users/akrzemi1/repos","events_url":"https://api.github.com/users/akrzemi1/events{/privacy}","received_events_url":"https://api.github.com/users/akrzemi1/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2016-03-04T12:44:50Z","updated_at":"2016-03-04T12:44:50Z","closed_at":null,"body":"[adapt_boost_variant.hpp](https://github.com/solodon4/Mach7/blob/master/code/mach7/adapters/boost/adapt_boost_variant.hpp) is a good start, but it isn't enough to understand the concept.\r\n\r\nE.g., what is `subtype_cast_impl` for? How Am I supposed to say that a reference to super-type should be cast to a reference to a sub-type?"}}