On Aug 13, 2007, at 16:29 , Benjamin Franksen wrote:
Let's take the simplest example: Maybe. The effect in question is the premature abortion of a computation (when Nothing is returned). And of course Maybe sequences these effects, that's what you use it for: the _first_ action to be encountered that returns Nothing aborts the computation. Clearly sequencing goes on here.
Clearly it does, but not as a side effect of the *monad*. It's ordinary Haskell data dependencies at work here, not some mystical behavior of a monad.
What about State? The effect is reading/writing the state. Again, the State Monad takes care that these effects get sequenced, and again that's what you expect it to do for you.
No, I expect it to carry a value around for me. If I carry that value around myself instead of relying on the monad to do it for me, *the calculation still gets sequenced by the data dependencies*. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH