2011/6/2 Șergiu Dumitriu <ser...@xwiki.com>: > On 06/02/2011 05:55 PM, Nathan Bubna wrote: >> >> Hi Andreas, >> >> Sorry to have inconvenienced you with this change. The old behavior >> was causing problems and had some notable flaws (see my discussion of >> the quirks in https://issues.apache.org/jira/browse/VELOCITY-681). >> There are no clean workarounds to recover the proxying behavior. You >> can set the original reference directly if you know it, of course, but >> that could get messy if a variety of references are passed in. You >> might also restructure to pass in references to objects or maps so >> that changes to the referenced variable are seen in the original >> reference when #set on the macro argument reference to that variable. >> I know neither of these is ideal. > > There is a trick that can be used to achieve the old behavior. I've detailed > the problem here: > http://www.xwiki.org/xwiki/bin/ReleaseNotes/ReleaseNotesXWikiEnterprise30#HMacroevaluationstrategy > > The solution is to use #evaluate to set the new value to the original > reference. The loophole that allows this to work is that > "$formalParameterName" expands to "$actualParameterName" when > $formalParameter is undefined/null. > > I've written a macro that does this: > https://github.com/xwiki/xwiki-platform/blob/e9051c85ae78fb973f4edbaa968db6bf235eb582/xwiki-platform-core/xwiki-platform-web/src/main/webapp/templates/macros.vm#L1131 > You use it by first setting the formal parameter to null, then calling > #setVariable("$formalParameterName" $value). > > By the way, will the loophole be preserved in future versions as well, or is > it in danger of being "fixed" at some point?
Oooh. That's a neat trick. I hadn't thought of that. As for the future, the loophole won't go anywhere in 1.x so long as i'm paying attention. In 2.0, i thought things were headed toward pass by value (courtesy of Byron's work/lobbying), but ya'll are welcome to work to keep the new status quo. I don't think there's a set consensus there, it's just been them that are doing the work on 2.x making the calls. Personally, i'm always drawn to support the preferences of those who are actively contributing, except when i don't. ;-) >> Sorry. >> >> On Thu, Jun 2, 2011 at 4:04 AM, Andreas Bohnert<a...@weberhofer.at> wrote: >>> >>> hello velocity user list, >>> >>> from the 1.7 release on we can not change the value of the original >>> reference of a macro argument anymore. >>> >>> this is the change log description: >>> Calling #set on a macro argument (for which a #set-able reference was >>> passed) will no longer propagate the new value to the original reference, >>> but merely set the value of the macro argument reference. This was an >>> obscure, infrequently used feature and was decided to be more problematic >>> and unpredictable than useful. >>> >>> so, is there still a way to change the value of the original reference if >>> I >>> want to? any workaround? >>> my knowledge of velocity is limited. I have read this one: >>> http://wiki.apache.org/velocity/MacroEvaluationStrategy >>> but I still did not manage to change the value. >>> >>> any help/example is very much appreciated!! >>> regards, Andreas > > > -- > Sergiu Dumitriu > http://purl.org/net/sergiu/ > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org > For additional commands, e-mail: user-h...@velocity.apache.org > > --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org For additional commands, e-mail: user-h...@velocity.apache.org
