I *think* you can set language level and target jdk on a per-module basis, so it should be relatively easy. I'll experiment at some point over the weekend. Would this complement or replace the I*Fn stuff do you think? 14.0 is not yet released, so I guess it's not too late to change if we want to.
On 11 December 2015 at 22:57, Josh Wills <josh.wi...@gmail.com> wrote: > That's the sexiest thing I've seen in some time. +1 for a lambda module, > but how does that work in Maven-fu? Is it like a conditional compile or > something? > > On Fri, Dec 11, 2015 at 1:20 PM, David Whiting <d...@apache.org> wrote: > > > Oops, my bad. Here's a Gist: > > https://gist.github.com/DavW/e2588e42c45ad8c06038 > > > > On 11 December 2015 at 18:43, Josh Wills <josh.wi...@gmail.com> wrote: > > > > > I think it's kind of awesome, but the attachment didn't go through- PR > or > > > gist? > > > On Fri, Dec 11, 2015 at 7:42 AM David Whiting <d...@apache.org> wrote: > > > > > > > While fixing the bug where the IFn version of mapValues on > > PGroupedTable > > > > was missing, I got thinking that this is quite an inefficient way of > > > > including support for lambdas and method references, and it still > > didn't > > > > actually support quite a few of the features that would make it easy > to > > > > code against. > > > > > > > > Negative parts of existing lambda implementation: > > > > 1) Explosion of already-crowded PCollection, PTable and PGroupedTable > > > > interfaces, and having to implement those methods in all > > implementations. > > > > 2) Not supporting flatMap to Optional or Stream types. > > > > 3) Not exposing convenient types for reduce-type operations (Stream > > > > instead of Iterable, for example). > > > > > > > > Something that would solve all three of these is to build lambda > > support > > > > as a separate artifact (so we can use all java8 types), and instead > of > > > the > > > > API being directly on the PSomething interfaces, we just have > > convenient > > > > ways to wrap up lambdas into DoFns or MapFns via statically-imported > > > > methods. > > > > > > > > The usage then becomes > > > > import static org.apache.crunch.Lambda.*; > > > > ... > > > > someCollection.parallelDo(flatMap(d -> someFnOf(d)), pt) > > > > ... > > > > otherGroupedTable.mapValue(reduce(seq -> seq.mapToInt(i -> i).sum()), > > > > ints()) > > > > > > > > Where flatMap and reduce are static methods on Lambda, and Lambda > goes > > in > > > > it's own artifact (to preserve compatibility with 6 and 7 for the > rest > > of > > > > Crunch). > > > > I've attached a basic proof-of-concept implementation which I've > > tested a > > > > few things with, and I'm very happy to sketch out a more substantial > > > > implementation if people here think it's a good idea in general. > > > > > > > > Thoughts? Ideas? Suggestions? Please tell me if this is crazy. > > > > > > > > > > > > > >
