As I said, Calcite doesn’t require a particular version of Guava. We support any version newer than 11.
But we would really, really appreciate it if you (and other downstream projects) moved off the obsoleted old versions. Julian > On Sep 6, 2016, at 8:29 PM, Andrew Purtell <[email protected]> wrote: > > Downstreamers might be stuck. > > Bringing together a number of components written against different versions > of Guava, you will find both forward and backward incompatibilities are > possible if stepping outside of a narrow range, and even at the same time. If > Calcite is required by something and itself requires yet another version of > Guava the viable intersection could become the null set. > > As a library, export of Guava types is unfriendly. > >> On Sep 6, 2016, at 7:18 PM, Julian Hyde <[email protected] >> <mailto:[email protected]>> wrote: >> >> Alternative proposal: >> We keep Guava in the public API. >> Down-streamers can use whatever version of Guava they choose. >> >> This is what we do today. It’s working fine (except that the down streamers >> seem to want to stay on old versions forever). >> >> Julian >> >> >>> On Sep 6, 2016, at 6:43 PM, Josh Elser <[email protected]> wrote: >>> >>> (from the peanut gallery) >>> >>> I have no strong opinions but find myself presently leaning towards Ted's >>> suggestions. >>> >>> Ideally, I think that we should not expose things in a "public API" which >>> we do not have the ability to guarantee compatibility of. A round-about way >>> of saying "Calcite public API should only be Calcite classes or Java >>> 'standard library' classes". Included Guava classes in the API would be >>> disallowed. The basic reasoning behind this is that it guarantees that we >>> have full control of our "destiny" without having to worry about dependency >>> versions. >>> >>> On the quick read of Ted's suggestion, it matches that (hide the Guava >>> class in the API's implementation with a generic type in the API). But, I >>> can also appreciate the problems you outline as well, Julian. >>> >>> Julian Hyde wrote: >>>> Yes, I misread your suggestion. I see now you are suggesting a compromise. >>>> The worst that can happen is that the API users make a few unnecessary >>>> defensive copies, or due to missing documentation they have to spend a >>>> little longer researching the API in order to discover that it is “safe”. >>>> >>>> I am not particularly inclined to compromise, because I would like Java to >>>> be a high level language. An immutable collection is inherently simpler >>>> than a mutable collection. Consider the problem of contravariance[1] in >>>> generics: if I have a function >>>> >>>> int countLegs(List<? extends Animal> animals) >>>> >>>> and I pass into it an argument of type >>>> >>>> List<? extends Dog> >>>> >>>> then the Java compiler rejects it, because it thinks that the function >>>> might try to add a Cat to the list. But we know that this is impossible, >>>> because countLegs does not modify the list. If immutability is part of the >>>> declared type of the list, the type validation rules can be looser. >>>> >>>> Julian >>>> >>>> [1] >>>> https://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)<https://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)> >>>> >>>> <https://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)%3Chttps://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)%3E><https://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)%3Chttps://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)%3E >>>> >>>> <https://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)%3Chttps://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)%3E>> >>>> >>>> >>>>> On Sep 6, 2016, at 2:41 PM, Ted Dunning<[email protected] >>>>> <mailto:[email protected]> <mailto:[email protected] >>>>> <mailto:[email protected]>>> wrote: >>>>> >>>>> Julian, >>>>> >>>>> I think you miss the point of my suggestion. >>>>> >>>>> String is not called ImmutableString. The contract of no immutability is >>>>> carried by outside tribal knowledge and documentation. It is enforced by >>>>> not allowing mutation. >>>>> >>>>> If you declare a List, but assign an ImmutableList, you are in a similar >>>>> situation except that the tribal knowledge has to be more forceful because >>>>> of the normal expectation of List as mutable. >>>>> >>>>> >>>>> >>>>>> On Wed, Sep 7, 2016 at 7:11 AM, Julian Hyde<[email protected] >>>>>> <mailto:[email protected]> <mailto:[email protected] >>>>>> <mailto:[email protected]>>> wrote: >>>>>> >>>>>> How bad would it be for API designers and users if java.lang.String were >>>>>> mutable? I would say really, really bad. You could add a lot of comments >>>>>> to >>>>>> the API documentation, but you’d never really be sure that everyone was >>>>>> adhering to the contract. >>>>>> >>>>>>> On Sep 6, 2016, at 1:59 PM, Ted Dunning<[email protected] >>>>>>> <mailto:[email protected]> <mailto:[email protected] >>>>>>> <mailto:[email protected]>>> wrote: >>>>>>> >>>>>>> What is so bad about declaring that variable as a List and making it an >>>>>>> ImmutableList underneath? >>>>>>> >>>>>>> Guard it in the programmer's mind by comments and naming. And if they >>>>>> don't >>>>>>> believe you, it still can't be changed. >>>>>>> >>>>>>> This avoids Guava leakage in the API and still gives you (nearly) all of >>>>>>> the benefits of the ImmutableList type. >>>>>>> >>>>>>> Kind of give a little to get a little. >>>>>>> >>>>>>> >>>>>>> >>>>>>>> On Wed, Sep 7, 2016 at 5:10 AM, Julian Hyde<[email protected] >>>>>>>> <mailto:[email protected]> <mailto:[email protected] >>>>>>>> <mailto:[email protected]>>> wrote: >>>>>>>> >>>>>>>> What is so bad about Guava? I have always found it to be a high quality >>>>>>>> library. I hear that they have broken backwards compatibility on one or >>>>>> two >>>>>>>> occasions, but I’ve never been affected by that personally. >>>>>>>> >>>>>>>>> On Sep 6, 2016, at 12:04 PM, Andrew Purtell<[email protected] >>>>>>>>> <mailto:[email protected]> <mailto:[email protected] >>>>>>>>> <mailto:[email protected]>>> >>>>>> wrote: >>>>>>>>> No argument that naming should set expectations of immutability if >>>>>> that's >>>>>>>>> what should be conveyed, but Guava types (or Guava anything) is a >>>>>>>>> means >>>>>>>> to >>>>>>>>> an end that can inflict significant pain on downstreamers. >>>>>>>>> >>>>>>>>>> On Tue, Sep 6, 2016 at 11:59 AM, Julian Hyde<[email protected] >>>>>>>>>> <mailto:[email protected]> <mailto:[email protected] >>>>>>>>>> <mailto:[email protected]>>> wrote: >>>>>>>>>> >>>>>>>>>> Calcite’s API has a large surface area. The API consists not just of >>>>>>>>>> method calls, but also data objects. For example, the Project class >>>>>> [1] >>>>>>>>>> represents a project node in a relational algebra expression. Its >>>>>>>>>> main >>>>>>>>>> field is “public final ImmutableList<RexNode> exps”. It is very >>>>>>>> important >>>>>>>>>> that everyone, especially the client, understands that that list is >>>>>>>>>> immutable. When you create a Project, you do not need to make a >>>>>>>> defensive >>>>>>>>>> copy of the list because no one is able to modify it. >>>>>>>>>> >>>>>>>>>> Imagine the mayhem if java.lang.String was mutable. As an API >>>>>>>>>> designer >>>>>>>> you >>>>>>>>>> would have to spell out whether the caller or the provider is allowed >>>>>> to >>>>>>>>>> change the string, and at what time. You would worry about thread >>>>>>>> safety, >>>>>>>>>> if the string has been shared with another thread. Well, I believe >>>>>> that >>>>>>>>>> Guava immutable collections prevent the same kinds of mayhem. I would >>>>>>>> call >>>>>>>>>> that good API design. >>>>>>>>>> >>>>>>>>>> The immutable collections and functions are in every Guava version, >>>>>>>>>> so >>>>>>>> we >>>>>>>>>> really don’t care which Guava version we use, as long as it is not >>>>>>>> shaded. >>>>>>>>>> Julian >>>>>>>>>> >>>>>>>>>> [1] https://calcite.apache.org/apidocs/org/apache/calcite/ >>>>>>>>>> rel/core/Project.html<https://calcite.apache.org/ >>>>>>>>>> apidocs/org/apache/calcite/rel/core/Project.html> >>>>>>>>>> >>>>>>>>>>>> On Sep 3, 2016, at 6:02 PM, Andrew Purtell<[email protected] >>>>>>>>>>> wrote: >>>>>>>>>>> I wouldn't call embedding Guava types in a public API either a >>>>>> service >>>>>>>>>> for users nor good API design, given the pain I've personally seen it >>>>>>>>>> inflict on multiple projects given Google's uncaring nature on cross >>>>>>>>>> version compatibility. >>>>>>>>>>>> On Sep 3, 2016, at 5:35 PM, Jacques Nadeau<[email protected]> >>>>>>>> wrote: >>>>>>>>>>>> Do you have a sense of how often we expose these? >>>>>>>>>>>> >>>>>>>>>>>> One random thought, shade Guava and continue to expose the >>>>>>>> shaded.guava >>>>>>>>>>>> classes in public APIs. >>>>>>>>>>>> >>>>>>>>>>>> People could choose to use the unshaded or shaded. >>>>>>>>>>>> >>>>>>>>>>>>> On Sat, Sep 3, 2016 at 11:26 AM, Julian Hyde<[email protected]> >>>>>>>> wrote: >>>>>>>>>>>>> I'm not keen on shading Guava, because I want to include some of >>>>>>>>>>>>> Guava's classes in Calcite's public API: for example ImmutableList >>>>>>>> and >>>>>>>>>>>>> Function. Using these classes in APIs makes better APIs. They >>>>>> should >>>>>>>>>>>>> be in the JDK, but sadly they're not, so we use Guava. >>>>>>>>>>>>> >>>>>>>>>>>>> Calcite's policy has been to support a wide range of Guava >>>>>>>>>>>>> versions >>>>>>>>>>>>> but to drop support for really old versions. We can use features >>>>>>>>>>>>> in >>>>>>>>>>>>> newer versions via reflection, as long as we don't introduce a >>>>>>>>>>>>> link >>>>>>>>>>>>> dependency (i.e. we call via reflection) and we can provide >>>>>> fallback >>>>>>>>>>>>> for older versions. All of this is identical to our policy for >>>>>> JDKs, >>>>>>>>>>>>> really. >>>>>>>>>>>>> >>>>>>>>>>>>> All we need is that our dependencies move off the really old >>>>>> versions >>>>>>>>>>>>> in a timely fashion. >>>>>>>>>>>>> >>>>>>>>>>>>> Julian >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> On Sat, Sep 3, 2016 at 10:20 AM, Andrew Purtell >>>>>>>>>>>>> <[email protected]> wrote: >>>>>>>>>>>>>> Use hbase-shaded-client as Maven dep (1.1 and up) >>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Sep 3, 2016, at 10:12 AM, James Taylor< >>>>>> [email protected]> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>> Does shading of protobuf on the HBase client work (or is that >>>>>>>>>> dependent >>>>>>>>>>>>> on >>>>>>>>>>>>>>> that brave work Stack is doing)? >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Sat, Sep 3, 2016 at 10:10 AM, Andrew Purtell< >>>>>>>>>>>>> [email protected]> >>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> James - When Stack is finished coprocessors will work with >>>>>> shaded >>>>>>>>>>>>>>>> protobuf. Not yet. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> On Sep 3, 2016, at 10:07 AM, James Taylor< >>>>>>>> [email protected] >>>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Also agree - shading of guava& protobuf would be super >>>>>> valuable. >>>>>>>>>>>>> Phoenix >>>>>>>>>>>>>>>>> ended up not supporting shading of protobuf because of >>>>>>>> difficulties >>>>>>>>>>>>>>>> getting >>>>>>>>>>>>>>>>> it to work (maybe because HBase dependency?). I think we >>>>>> support >>>>>>>>>>>>> shading >>>>>>>>>>>>>>>> of >>>>>>>>>>>>>>>>> Guava, though. Is that correct, Sergey? >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> On Sat, Sep 3, 2016 at 10:02 AM, Jacques Nadeau< >>>>>>>>>> [email protected]> >>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>> +1 on shading guava/protobuf. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> On Sat, Sep 3, 2016 at 9:48 AM, Andrew Purtell< >>>>>>>>>>>>>>>> [email protected]> >>>>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> Since Calcite should become a widely used library (smile) I >>>>>>>>>> think it >>>>>>>>>>>>>>>>>> would >>>>>>>>>>>>>>>>>>> be prudent to shade Guava and protobuf if Calcite depends on >>>>>>>>>> them. >>>>>>>>>>>>> Then >>>>>>>>>>>>>>>>>> you >>>>>>>>>>>>>>>>>>> will play very nicely indeed on the classpath no matter what >>>>>>>>>>>>> versions >>>>>>>>>>>>>>>> are >>>>>>>>>>>>>>>>>>> required by calling code. >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> Jacques - Good lord. Let me see about shading HBase use of >>>>>>>>>> Guava, or >>>>>>>>>>>>>>>>>>> eliminating it. Unfortunately that will be no help in the >>>>>> short >>>>>>>>>>>>> term. >>>>>>>>>>>>>>>>>>> Related, our Stack is wrestling with shading protobuf >>>>>> already, >>>>>>>>>> and >>>>>>>>>>>>> is >>>>>>>>>>>>>>>>>> neck >>>>>>>>>>>>>>>>>>> deep in the Swamp of Classloading at the moment. >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> On Sep 3, 2016, at 9:06 AM, Jacques Nadeau< >>>>>>>> [email protected]> >>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>>>> It isn't a real solution but in Drill we solved the HBase >>>>>>>>>>>>>>>>>> incompatibility >>>>>>>>>>>>>>>>>>>> issue on the server side (for tests only) by patching Guava >>>>>> 18 >>>>>>>>>> to >>>>>>>>>>>>>>>> allow >>>>>>>>>>>>>>>>>>> the >>>>>>>>>>>>>>>>>>>> HBase Guava calls that are missing. They are really quite >>>>>>>>>> trivial >>>>>>>>>>>>> and >>>>>>>>>>>>>>>>>>>> support Andrew's arguments that Guava is the devil... >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> https://github.com/apache/drill/blob/master/exec/java- >>>>>>>>>>>>>>>>>>> exec/src/main/java/org/apache/drill/exec/util/GuavaPatcher. >>>>>>>> java >>>>>>>>>>>>>>>>>>>> On Sat, Sep 3, 2016 at 8:16 AM, Andrew Purtell< >>>>>>>>>>>>>>>>>> [email protected] >>>>>>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> While that seems very unfriendly of them, the main issue >>>>>>>>>>>>>>>>>>>>> is >>>>>>>>>> Guava >>>>>>>>>>>>> is >>>>>>>>>>>>>>>>>> the >>>>>>>>>>>>>>>>>>>>> devil (and protobuf is a minor demon). Would shading be an >>>>>>>>>> option? >>>>>>>>>>>>>>>>>>>>>> On Sep 3, 2016, at 2:03 AM, CPC<[email protected]> >>>>>> wrote: >>>>>>>>>>>>>>>>>>>>>> Cassandra driver 3.x require min guava 16.0.1. If it >>>>>> detects >>>>>>>>>> an >>>>>>>>>>>>>>>>>> earlier >>>>>>>>>>>>>>>>>>>>>> version in classpath it stops working. >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> On Sep 3, 2016 04:26, "Julian Hyde"<[email protected]> >>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>>>>>>> James& Andrew, I hear you. We’ll stay on Guava 12 if we >>>>>>>> have >>>>>>>>>>>>> to. >>>>>>>>>>>>>>>>>>>>>>> But can we try an experiment to see if it’s possible to >>>>>> get >>>>>>>>>> away >>>>>>>>>>>>>>>>>> with >>>>>>>>>>>>>>>>>>>>> 14? >>>>>>>>>>>>>>>>>>>>>>> I propose that Maryann (who is developing the branch of >>>>>>>>>> Phoenix >>>>>>>>>>>>>>>> that >>>>>>>>>>>>>>>>>>>>> uses >>>>>>>>>>>>>>>>>>>>>>> Calcite) tries running with https://github.com/apache/ >>>>>>>>>>>>>>>>>>> calcite/pull/277 >>>>>>>>>>>>>>>>>>>>> < >>>>>>>>>>>>>>>>>>>>>>> https://github.com/apache/calcite/pull/277>. If we >>>>>>>> discover >>>>>>>>>>>>>>>>>> problems, >>>>>>>>>>>>>>>>>>>>> we >>>>>>>>>>>>>>>>>>>>>>> can try various solutions, like make the DateRangeRules >>>>>>>>>>>>> disabled by >>>>>>>>>>>>>>>>>>>>> default >>>>>>>>>>>>>>>>>>>>>>> (these, and the Druid adapter, are the only parts of >>>>>>>> Calcite >>>>>>>>>>>>> that >>>>>>>>>>>>>>>>>> need >>>>>>>>>>>>>>>>>>>>>>> Guava 14), or even copy the Guava classes that we need. >>>>>> If >>>>>>>>>> there >>>>>>>>>>>>>>>>>>> aren’t >>>>>>>>>>>>>>>>>>>>>>> problems, it means that we’ve slipped out of the >>>>>>>>>>>>>>>>>>>>>>> shackles >>>>>>>> of >>>>>>>>>>>>>>>> inertia >>>>>>>>>>>>>>>>>>>>> that >>>>>>>>>>>>>>>>>>>>>>> are trying to drag us into an early grave. >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> Julian >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>> On Sep 2, 2016, at 5:35 PM, James Taylor< >>>>>>>>>>>>> [email protected]> >>>>>>>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>>>>>>>> On the server-side, HBase depends on Guava 12 (because >>>>>>>>>> Hadoop >>>>>>>>>>>>>>>>>> depends >>>>>>>>>>>>>>>>>>>>> on >>>>>>>>>>>>>>>>>>>>>>>> the same). For that reason, we've made sure Phoenix can >>>>>>>> work >>>>>>>>>>>>> with >>>>>>>>>>>>>>>>>>> this >>>>>>>>>>>>>>>>>>>>>>>> version too. Phoenix may not need to depend on Calcite >>>>>> on >>>>>>>>>> the >>>>>>>>>>>>>>>>>>>>>>> server-side, >>>>>>>>>>>>>>>>>>>>>>>> and Phoenix and HBase both have shading, so there may >>>>>>>>>>>>>>>>>>>>>>>> be >>>>>>>>>> some >>>>>>>>>>>>>>>>>> avenues >>>>>>>>>>>>>>>>>>>>> of >>>>>>>>>>>>>>>>>>>>>>>> escape. >>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>> Sorry for the muddled answer. >>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>> On Fri, Sep 2, 2016 at 5:21 PM, Andrew Purtell< >>>>>>>>>>>>>>>>>> [email protected] >>>>>>>>>>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>> Use of Guava 14 introduces at least a compile time >>>>>>>> problem >>>>>>>>>>>>> with >>>>>>>>>>>>>>>>>>> HBase, >>>>>>>>>>>>>>>>>>>>>>> upon >>>>>>>>>>>>>>>>>>>>>>>>> which Phoenix depends, so I'm not sure Phoenix can >>>>>>>>>>>>>>>>>>>>>>>>> move >>>>>>>>>> off of >>>>>>>>>>>>>>>> 13. >>>>>>>>>>>>>>>>>>> I'd >>>>>>>>>>>>>>>>>>>>>>> be >>>>>>>>>>>>>>>>>>>>>>>>> happy to be proven wrong. >>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>>> On Fri, Sep 2, 2016 at 4:35 PM, Julian Hyde< >>>>>>>>>>>>> [email protected]> >>>>>>>>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>>>>>>>>>>>>> Calcite currently supports a wide range of Guava >>>>>>>> versions, >>>>>>>>>>>>> from >>>>>>>>>>>>>>>>>>>>> 12.0.1 >>>>>>>>>>>>>>>>>>>>>>> to >>>>>>>>>>>>>>>>>>>>>>>>>> 19.0*. For https://issues.apache.org/ >>>>>>>>>>>>> jira/browse/CALCITE-1334< >>>>>>>>>>>>>>>>>>>>>>>>>> https://issues.apache.org/jira/browse/CALCITE-1334> >>>>>> I’d >>>>>>>>>>>>> like to >>>>>>>>>>>>>>>>>>> use >>>>>>>>>>>>>>>>>>>>>>>>>> RangeSet, which was introduced in Guava 14. >>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>>> Would anyone have a problem if we made Calcite’s >>>>>> minimum >>>>>>>>>>>>> Guava >>>>>>>>>>>>>>>>>>>>> version >>>>>>>>>>>>>>>>>>>>>>>>>> 14.0.1? >>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>>> I see that Hive uses 14.0.1, Phoenix uses 13, Drill >>>>>> uses >>>>>>>>>> 18. >>>>>>>>>>>>>>>>>>>>>>>>>> Julian >>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>>> * Except for the Druid adapter, which requires 14; >>>>>>>>>>>>>>>>>>>>>>>>>> see >>>>>>>>>>>>>>>>>>>>>>>>>> https://issues.apache.org/jira/browse/CALCITE-1325< >>>>>>>>>>>>>>>>>>>>>>>>>> https://issues.apache.org/jira/browse/CALCITE-1325> >>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>>>>>>>>>>> Best regards, >>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>> - Andy >>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>> Problems worthy of attack prove their worth by hitting >>>>>>>>>> back. - >>>>>>>>>>>>>>>>>> Piet >>>>>>>>>>>>>>>>>>>>> Hein >>>>>>>>>>>>>>>>>>>>>>>>> (via Tom White) >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Best regards, >>>>>>>>> >>>>>>>>> - Andy >>>>>>>>> >>>>>>>>> Problems worthy of attack prove their worth by hitting back. - Piet >>>>>> Hein >>>>>>>>> (via Tom White)
