LINQ does the same thing for C#, the translation is more like a macro than anything that really knows what a monad is.
On Tue, Jul 31, 2012 at 1:39 PM, Kevin Wright <[email protected]>wrote: > You can implement FilterMonadic if you want, but the compiler doesn't > demand that you do. > > It's more useful as a marker trait, and to be sure that you've implemented > all the methods that you intended to implement. > > comprehensions are transformed to map/flatMap/etc. very early on in the > compiler, and certainly don't rely on any type information. > > > > On 31 July 2012 14:45, Dale Wijnand <[email protected]> wrote: > >> Doesn't that mean it must >> implement scala.collection.generic.FilterMonadic? >> (or is it scala.collection.GenTraversableOnce..) >> >> Dale >> >> On 31 July 2012 14:46, Kevin Wright <[email protected]> wrote: >> >>> Without lambdas, you're a bit limited here. But with them, I've found >>> scala's approach to work well. >>> >>> for(x <- xs) { println(x) } >>> >>> is just syntactic sugar for >>> >>> xs foreach { x => println(x) } >>> >>> >>> >>> and >>> >>> for(x <- xs) yield { x.toUpperCase } >>> >>> is >>> >>> xs map { x => x.toUpperCase } >>> >>> >>> *anything* with the appropriate map/flatMap/filter/foreach method(s) on >>> can be used in a for-comprehension. >>> (which is why scala doesn't call it a "for loop", because it really >>> isn't) >>> >>> >>> On 31 July 2012 13:31, Dale Wijnand <[email protected]> wrote: >>> >>>> I would say you could create delegating iterables/iterators for those >>>> types. What would be an alternative would you have preferred? >>>> >>>> Dale >>>> >>>> On 31 July 2012 14:17, Kevin Wright <[email protected]> wrote: >>>> >>>>> Yes/No. You're still forced to only use it with things that can be >>>>> Iterables, yet there's a whole category of stuff where foreach makes >>>>> sense, >>>>> but can't be represented in this manner. >>>>> >>>>> One of the more obvious examples here is something like a stream of >>>>> lines coming over a network socket, in which you want the body of the >>>>> foreach expression to be executed asynchronously for each incoming line >>>>> (perhaps by dispatching to a thread pool), and for the expression as a >>>>> whole to be non-blocking. >>>>> >>>>> >>>>> On 31 July 2012 08:15, Roland Tepp <[email protected]> wrote: >>>>> >>>>>> Sorry, couldn't resist, but let your class implement Iterable and >>>>>> voila - the foreach is extended! >>>>>> >>>>>> esmaspäev, 30. juuli 2012 15:55.30 UTC+3 kirjutas Ricky Clarkson: >>>>>> >>>>>>> 6. foreach is not open for extension, i.e., it only works with >>>>>>> Iterables and arrays. >>>>>>> >>>>>> >>>>> >>>>> >>> -- > You received this message because you are subscribed to the Google Groups > "Java Posse" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/javaposse?hl=en. > -- You received this message because you are subscribed to the Google Groups "Java Posse" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/javaposse?hl=en.
