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You can reach the person managing the list at beginners-ow...@haskell.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Beginners digest..." Today's Topics: 1. newEmptyMVar return type (Velichko Lefterov) 2. Re: newEmptyMVar return type (Velichko Lefterov) 3. Re: newEmptyMVar return type (David McBride) ---------------------------------------------------------------------- Message: 1 Date: Tue, 5 Jan 2021 20:22:50 +0200 From: Velichko Lefterov <velichko.lefte...@gmail.com> To: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level topics related to Haskell <beginners@haskell.org> Subject: [Haskell-beginners] newEmptyMVar return type Message-ID: <cajuu68v5y0xwyepyvsm6o3qnav4bahacq3xt8tmkc1p7ttb...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" Hello, could someone explain me simple how return-type polymorphism works in the following case: newEmptyMVar :: IO (MVar a) ? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.haskell.org/pipermail/beginners/attachments/20210105/534a8674/attachment-0001.html> ------------------------------ Message: 2 Date: Wed, 6 Jan 2021 08:37:03 +0200 From: Velichko Lefterov <velichko.lefte...@gmail.com> To: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level topics related to Haskell <beginners@haskell.org> Subject: Re: [Haskell-beginners] newEmptyMVar return type Message-ID: <CAJuu68v3MDC-MCO_Sd-58YOw_vqgMXvQq45j8Duw4O=_gge...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" OK, I tried this one: test:: IO (Maybe a) test = return Nothing It looks similar and it seems to work... On Tue, Jan 5, 2021 at 8:22 PM Velichko Lefterov < velichko.lefte...@gmail.com> wrote: > Hello, > could someone explain me simple how return-type polymorphism works > in the following case: > newEmptyMVar :: IO (MVar a) ? > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.haskell.org/pipermail/beginners/attachments/20210106/cfc7ecaa/attachment-0001.html> ------------------------------ Message: 3 Date: Wed, 6 Jan 2021 06:37:52 -0500 From: David McBride <toa...@gmail.com> To: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level topics related to Haskell <Beginners@haskell.org> Subject: Re: [Haskell-beginners] newEmptyMVar return type Message-ID: <can+tr41ecoxgwtl4krbkuyvu6nknnt9wfb0zn+i-ydvcn10...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" It means that the function can return an mvar containing any type that you need. What type it returns depends on what type your program asks for. On Wed, Jan 6, 2021, 01:37 Velichko Lefterov <velichko.lefte...@gmail.com> wrote: > OK, > I tried this one: > > test:: IO (Maybe a) > test = return Nothing > > It looks similar and it seems to work... > > On Tue, Jan 5, 2021 at 8:22 PM Velichko Lefterov < > velichko.lefte...@gmail.com> wrote: > >> Hello, >> could someone explain me simple how return-type polymorphism works >> in the following case: >> newEmptyMVar :: IO (MVar a) ? >> > _______________________________________________ > Beginners mailing list > Beginners@haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.haskell.org/pipermail/beginners/attachments/20210106/74e93078/attachment-0001.html> ------------------------------ Subject: Digest Footer _______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners ------------------------------ End of Beginners Digest, Vol 150, Issue 4 *****************************************