[Haskell-cafe] Trapping getChar before echo
Andrew Coppin
andrewcoppin at btinternet.com
Sun Jan 31 07:57:44 EST 2010
Michael Hartl wrote:
> import System.IO
> import Data.Char
>
> main = do
> hSetEcho stdin False
> hSetBuffering stdin NoBuffering
> hSetBuffering stdout NoBuffering
> scanLine
> where scanLine = do
> c <- hGetChar stdin
> putChar . toUpper $ c
> scanLine
>
Last time I tried something like this [on Windows], it didn't seem to
work. I wanted to trap arrow keys and so forth, but they seem to be
being used for input history. (I.e., pressing the up-arrow produces
previously-entered lines of text, and none of this appears to be
reaching the Haskell program itself.) Has this changed since I tried it
last year?
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