Brandon S. Allbery KF8NH
allbery at ece.cmu.edu
Mon Oct 15 10:00:50 EDT 2007
On Oct 15, 2007, at 9:48 , Brandon S. Allbery KF8NH wrote:
> On Oct 15, 2007, at 7:02 , jerzy.karczmarczuk at info.unicaen.fr wrote:
>> IO is different, you *cannot* make it non-monadic.
> Not really true; it's just much more painful.
Expanding on this slightly: the neat thing about Haskell's monads is
not that they are somehow not "pure". It is that they a completely
pure and referentially transparent way to capture and safely
encapsulate concepts that themselves may *not* be pure or
referentially transparent, such as IO --- while simultaneously being
useful for concepts that *are* pure and referentially transparent,
such as State or Maybe/Either/.
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university KF8NH
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