[Haskell-cafe] Too much strictness in binary-

Duncan Coutts duncan.coutts at googlemail.com
Sun Oct 18 13:21:37 EDT 2009

On Sun, 2009-10-18 at 19:53 +0400, Alexey Khudyakov wrote:
> > Yes. We decided that having the Get monad as a lazy state monad just
> > doesn't make sense. It makes this one use case work, but causes more
> > problems generally. Certainly we need to be able to do lazy binary
> > deserialisation too, but our feeling is that it should be more explicit
> > and integrate better with error handling. Using a lazy state monad gives
> > us neither.
> This is valid point. I think I'll just use variant with explicit laziness.
> > Note also that if we changed runGetState to do any error handling that
> > this would also break the lazy state monad properties that you were
> > previously relying upon.
> I'd appreciate addition of error handling very much. Currently I have
> to use ErrorT and do checks by hands. I have very simple parsers so
> it's possible. It's not possible to do such things in general.
> Trading laziness for error handling is good thing I believe. At the
> moment it's hard to decode possibly malformed data.

It's possible to have both error handling and lazyness by extending the
result to include the representation of the errors.


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