RE: [Haskell-cafe] Re: IO exception not being caught
Indeed! I always use braces and semicolons with do-notation. You are free to do so too! Nothing requires you to use layout. Indeed, you can freely mix the two. Simon | -Original Message- | From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Joel | Reymont | Sent: 16 November 2005 15:37 | To: Haskell Cafe | Subject: [Haskell-cafe] Re: IO exception not being caught | | After almost two months with Haskell I'm starting to understand why | its use is not as widespread as... well pick a favorite language of | your own. My issue was that of indentation. | | Compare this working version: | | liftIOTrap io = | do mx - liftIO (do x - io | return (return x) | `catchError` | (\e - do let x = fromIOError e | trace_ $ Caught ++ x | return $ throwError x | )) | mx | | With the one below | | On Nov 16, 2005, at 2:27 PM, Joel Reymont wrote: | | liftIOTrap io = | do mx - liftIO (do x - io | return (return x) | `catchError` | (\e - return (throwError |(fromIOError e | mx | | -- | http://wagerlabs.com/ | | | | | | ___ | Haskell-Cafe mailing list | Haskell-Cafe@haskell.org | http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: IO exception not being caught
Hello Joel, Wednesday, November 16, 2005, 6:37:25 PM, you wrote: JR After almost two months with Haskell I'm starting to understand why JR its use is not as widespread as... well pick a favorite language of JR your own. My issue was that of indentation. just enclose potentially problematic do ... in parentheses: JR liftIOTrap io = JR do mx - liftIO (do x - io JR return (return x) can be written as do mx - liftIO ((do x - io return (return x)) and after that you can put `catchError` to any position in the line -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
