On 14 December 2011 20:21, Gregory Crosswhite <gcrosswh...@gmail.com> wrote: > > On Dec 14, 2011, at 4:40 PM, Ivan Lazar Miljenovic wrote: > > [...] Apart from some > > basic combinators in Control.Monad or the definitions of monad > transformers, how much of what you write in do-blocks is applicable to > some generic Monad instance as opposed to a specific Monad? > > > Well, if my *only* constraint on a type is that it be an instance of Monad, > then *all* of the code written in do-blocks will be applicable to a generic > Monad instance. That's the whole point. :-) > > Furthermore, you make it sound like this generic case scenario is incredibly > rare, but in fact it is very common: it occurs whenever someone writes a > monadic transformer, which happens all the time. Imagine what writing > monadic transformers would be like if you couldn't always trust that, say, > (>>=) was a well-defined operation?
What I was trying to reference was times when I use the list monad as a pseudo-prolog, or the Maybe monad as a "stop when failed" case, etc.: trying to use one for the other doesn't always work. -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
