[Haskell-cafe] Data.Binary and error handling

[Khudyakov Alexey]

В сообщении от 27 ноября 2009 23:55:47 Don Stewart написал:
> alexey.skladnoy:
> > It does but it was already noted that cereal uses strict bytestrings
> > which are not really convenient when dealing with huge inputs. One may
> > end up using both binary and cereal which is not really satisfactory.
> 
> It is quite hard to do a good job of lazy input, but explicit checked
> errors (turning it into an Either Error a makes the whole stream
> strict!).
> 
Surprisingly it seems that it's not possible to avoid "unexpected end of input 
error" without forcing input. Primitive parsers fail in that case and only 
reasonably way to check against this is 'remaining' function which forces 
input. Moreover it's very inconvenient to check before significant fraction of 
calls that input has sufficient length.

Of course it's possible to implement robust parsers with getWord8 & isEmpty 
duo but this is theoretical possibility.