Simon Peyton-Jones wrote:
> | In 7.1, the Report says of getChar, getContents and friends: > | > | "By default, these input functions echo to standard output." > | > | This would mean that the example given: > | > | main = interact (filter isAscii) > | > | would print the input with all ASCII characters duplicated. > | > | Surely it should say that if the standard input is a terminal device the > | input is echoed on that device. Or maybe the sentence should be deleted. > > Ross's speaks truth. In fact, the overall behaviour of a Haskell > program when used from a terminal ought to be predicable regardless of > OS. And indeed one expects the behaviour to differ depending on whether > stdin is a terminal or a file. > > So I propose to adopt Ross's modification: "Surely it should say that if > the standard input is a terminal device the input is echoed on that > device." This describes what Haskell implementations actually do, and > it describes the desired behaviour. > > All this is about the Language Report. In the Library Report, it says > that "getLine" is sort for "hGetLine stdin". So that implies that > > If the standard input (stdin) is a terminal device, > any input on stdin is echoed on that device > > So, for consistency, I propose to add that to the IO chapter of the > library report. > > Does that seem right? No. A terminal device may echo or it may not. Even if the run-time explicitly enables echoing, there is no guarantee that it won't subsequently be disabled. Certainly, the existing statement is wrong, though. -- Glynn Clements <[EMAIL PROTECTED]> _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
