{"action":"created","issue":{"url":"https://api.github.com/repos/commercialhaskell/stack/issues/2104","repository_url":"https://api.github.com/repos/commercialhaskell/stack","labels_url":"https://api.github.com/repos/commercialhaskell/stack/issues/2104/labels{/name}","comments_url":"https://api.github.com/repos/commercialhaskell/stack/issues/2104/comments","events_url":"https://api.github.com/repos/commercialhaskell/stack/issues/2104/events","html_url":"https://github.com/commercialhaskell/stack/issues/2104","id":153248721,"number":2104,"title":"stack ghci --fast seems undocumented","user":{"login":"simonmichael","id":10144,"avatar_url":"https://avatars.githubusercontent.com/u/10144?v=3","gravatar_id":"","url":"https://api.github.com/users/simonmichael","html_url":"https://github.com/simonmichael","followers_url":"https://api.github.com/users/simonmichael/followers","following_url":"https://api.github.com/users/simonmichael/following{/other_user}","gists_url":"https://api.github.com/users/simonmichael/gists{/gist_id}","starred_url":"https://api.github.com/users/simonmichael/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/simonmichael/subscriptions","organizations_url":"https://api.github.com/users/simonmichael/orgs","repos_url":"https://api.github.com/users/simonmichael/repos","events_url":"https://api.github.com/users/simonmichael/events{/privacy}","received_events_url":"https://api.github.com/users/simonmichael/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2016-05-05T14:52:06Z","updated_at":"2016-05-05T21:51:02Z","closed_at":null,"body":"I wonder what the ghci command's `--fast` flag does, and I don't see it in the user guide."},"comment":{"url":"https://api.github.com/repos/commercialhaskell/stack/issues/comments/217290377","html_url":"https://github.com/commercialhaskell/stack/issues/2104#issuecomment-217290377","issue_url":"https://api.github.com/repos/commercialhaskell/stack/issues/2104","id":217290377,"user":{"login":"mgsloan","id":22570,"avatar_url":"https://avatars.githubusercontent.com/u/22570?v=3","gravatar_id":"","url":"https://api.github.com/users/mgsloan","html_url":"https://github.com/mgsloan","followers_url":"https://api.github.com/users/mgsloan/followers","following_url":"https://api.github.com/users/mgsloan/following{/other_user}","gists_url":"https://api.github.com/users/mgsloan/gists{/gist_id}","starred_url":"https://api.github.com/users/mgsloan/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mgsloan/subscriptions","organizations_url":"https://api.github.com/users/mgsloan/orgs","repos_url":"https://api.github.com/users/mgsloan/repos","events_url":"https://api.github.com/users/mgsloan/events{/privacy}","received_events_url":"https://api.github.com/users/mgsloan/received_events","type":"User","site_admin":false},"created_at":"2016-05-05T21:51:02Z","updated_at":"2016-05-05T21:51:02Z","body":"It comes from `stack ghci` taking all the same options as `stack build`.  For `stack build`, it uses `-O0`.  For ghci itself it doesn't do much, except for when ghci does an initial build (which can be suppressed via `--no-build`, something I use with most of my invocations).\r\n\r\n`stack ghci` has gotten quite powerful, and a little tricky to use to its full potential.  I think it really needs its own dedicated documentation page https://github.com/commercialhaskell/stack/issues/1896"}}