On 17 feb 2008, at 08.46, Anton van Straaten wrote:
Colin Paul Adams wrote:
"Cale" == Cale Gibbard <[EMAIL PROTECTED]> writes:
Cale> So, the first version:
Cale> import System.IO import Control.Exception (try)
Cale> main = do mfh <- try (openFile "myFile" ReadMode) case mfh
Cale> of Left err -> do putStr "Error opening file for reading: "
Cale> print err Right fh -> do mline <- try (hGetLine fh) case
Cale> mline of Left err -> do putStr "Error reading line: " print
Cale> err hClose fh Right line -> putStrLn ("Read: " ++ line)
Left? Right?
Hardly descriptive terms. Sounds like a sinister language to me.
I was thinking along the same lines. Politically-sensitive left-
handed people everywhere ought to be offended that "Left" is the
alternative used to represent errors, mnemonic value notwithstanding.
Is there a benefit to reusing a generic Either type for this sort
of thing? For code comprehensibility, wouldn't it be better to use
more specific names? If I want car and cdr, I know where to find it.
Haskell doesn't have constructor aliases and keeping around dozens of
isomorphic types would be stupid. (Views could help, though.)
Also, "Right" is naturally used when the everything was alright. It
might be arbitrary, but it's not hard to remember - once you're past
the newbie phase no-one confuses car and cdr anyways...
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