No problem, thanks for making things clear. << we decided to forego it and notify users of the non-BC change when we released 1.7.
which notification are you referring to? Wonder if there is something else in there I am not aware of. On Mon, Apr 30, 2012 at 2:34 PM, Nathan Bubna <nbu...@gmail.com> wrote: > Congratulations, Boris. You are the corner case we feared. :-/ We > knew when we went ahead with this that providing a migration path > would be difficult. We knew most users didn't have extreme numbers of > macros and hoped that those who didn't frequently nest them, in part > because of the complexities of heavy scoping in a language that often > treated scoping as a second-class feature, and in part because of the > performance issues macros had prior to 1.6. #parse, > VelocityLayoutServlet and even custom tools, which lack the implicit > scoping support, tended to be more performant and encouraged for > simplifying complicated tools. Considering those things and the > difficulty of implementing a BC switch for implicit scoping, we > decided to forego it and notify users of the non-BC change when we > released 1.7. > > Sorry. It sounds like it's going to take some legwork to upgrade in > the cases where you nested your macros. > > On Mon, Apr 30, 2012 at 11:16 AM, Boris Partensky > <boris.parten...@gmail.com> wrote: >> Yep, I am afraid we do set globals from within macros... >> >> On Mon, Apr 30, 2012 at 2:05 PM, Nathan Bubna <nbu...@gmail.com> wrote: >>> Can you set velocimacro.context.localscope = true or is it important >>> for your system to be able to #set global stuff from within macros? >>> >>> On Mon, Apr 30, 2012 at 10:50 AM, Boris Partensky >>> <boris.parten...@gmail.com> wrote: >>>> Thanks Nathan, I think I do get the whole scoping idea, but my >>>> understanding was that one of the reasons to turn all scoping off by >>>> default (and have those properties to begin with) was to provide >>>> backward compatibility - as in: I upgrade to 1.7 and then I start >>>> turning on all those nice bells and whistles and use scopes and what >>>> not. Not so seems like? I also find somewhat strange that a a formal >>>> argument to a macro takes precedence and overwrites a global variable >>>> with the same name. How would one go about upgrading existing systems? >>>> We have roughly 1900 macros, big chunk of those are nested... Maybe I >>>> am misunderstanding something, but this issue makes it almost >>>> impossible to upgrade (at least for us). >>>> >>>> >>>> Thanks >>>> Boris >>>> >>>> On Mon, Apr 30, 2012 at 12:55 PM, Nathan Bubna <nbu...@gmail.com> wrote: >>>>> Yeah, it was intended, and part of an overall move toward >>>>> fixing/simplifying Velocity's variable scoping, avoiding the >>>>> complexities and costs (performance, yes, but mostly time/brainpower >>>>> for users and devs alike) of more programming language type behavior. >>>>> Velocity has long aspired to be a straightfoward template engine and >>>>> avoid being a complete scripting language. (Implicit) variable >>>>> scoping, as seen in 1.5, was seen as a necessary compromise toward the >>>>> latter; after all, one big fat namespace is always unmanageable, >>>>> right? Well, there's ways to make that easy to manage. :) Let's call >>>>> it "optional, provided, explicit scoping", explicit because you don't >>>>> have to grok the contextual scope to understand a reference, optional >>>>> because you can ignore it, and provided because Velocity does the work >>>>> of choosing "prefixes" and creating/destroying the scopes (as any >>>>> implicit scoping system does). So everything is becoming globally >>>>> scoped, but it is now trivial to turn on automatic, explicit scopes or >>>>> namespaces that you can use when you don't want things to live in the >>>>> global scope. >>>>> >>>>> Here's an example... Do you use $velocityCount to get an index of >>>>> sorts inside of #foreach directives? Well, that's an example of mixed >>>>> implicit/explicit namespacing that gets messy when you nest >>>>> #foreach's, with no good way to get the parent's count and >>>>> unwieldiness when you want to add $velocityIndex, $velocityHasNext and >>>>> so on. Now, we automatically manage a $foreach var that not only has >>>>> a 'count' property, but an 'index', 'hasNext', 'parent', and so on >>>>> (see >>>>> http://velocity.apache.org/engine/devel/apidocs/org/apache/velocity/runtime/directive/ForeachScope.html). >>>>> It also, of course, accepts any property you want to set on it (like >>>>> any map). This makes templates instantly understandable, making >>>>> debugging much better. You always know exactly what you are referring >>>>> to, and so does anyone else reading the template. >>>>> >>>>> #foreach is the only 'content directive' that has its explicit scope >>>>> automatically turned on, but all content containing directives >>>>> (including custom body macros) can have their own explicit, >>>>> auto-managed scope, named after themselves. for example, you can flip >>>>> the macro scope on: >>>>> >>>>> macro.provide.scope.control = true >>>>> >>>>> and do: >>>>> >>>>> #macro( outer $arg ) >>>>> #set( $macro.arg = $arg ) >>>>> #inner( 'inner' ) >>>>> #end >>>>> #macro( inner $arg ) >>>>> #set( $macro.arg = $arg) >>>>> inner: $macro.arg >>>>> #if( $macro.parent )outer: $macro.parent.arg#end >>>>> #end >>>>> >>>>> #outer( 'outer' ) >>>>> #inner( 'just inner' ) >>>>> >>>>> and get >>>>> >>>>> inner: inner >>>>> outer: outer >>>>> inner: just inner >>>>> >>>>> Hope this helps... >>>>> >>>>> In any case, there was plenty of thought and discussion that went into >>>>> this change. Search http://velocity.markmail.org for 'scope' and you >>>>> should find more on this. >>>>> >>>>> On Mon, Apr 30, 2012 at 8:49 AM, Boris Partensky >>>>> <boris.parten...@gmail.com> wrote: >>>>>> Hello, while going through the upgrade I noticed an incompatible >>>>>> behavior during nested macro evaluation. Looks like in 1.7 (all >>>>>> default properties) child macro has access to variables set in parent >>>>>> macro scope (and those take precedence over globals), and 1.5 sees >>>>>> globals. In the following example, in 1.5 unit test the following >>>>>> template will evaluate to "globalvar", and in 1.7 - to >>>>>> "outermacroparam". Is this expected behavior? >>>>>> >>>>>> >>>>>> 1.5 test case >>>>>> >>>>>> >>>>>> public void testVelocityNestedMacroScope() throws Exception >>>>>> { >>>>>> VelocityEngine ve = new VelocityEngine(); >>>>>> >>>>>> ve.init(); >>>>>> >>>>>> String template = "#macro(outerMacro $arg1)"+ >>>>>> "#innerMacro('blah')"+ >>>>>> "#end"+ >>>>>> "#macro(innerMacro $arg2)$arg1#end"+ >>>>>> >>>>>> "#set($arg1='globalval')#outerMacro('outermacroparam')"; >>>>>> StringWriter eval = new StringWriter(); >>>>>> boolean b = ve.evaluate(new VelocityContext(), eval, "foo", >>>>>> template); >>>>>> assertEquals(eval.toString(), "globalval", eval.toString()); >>>>>> >>>>>> } >>>>>> >>>>>> 1.7 test case >>>>>> >>>>>> >>>>>> public void testVelocityNestedMacroScope() >>>>>> { >>>>>> String template = "#macro(outerMacro $arg1)"+ >>>>>> "#innerMacro('blah')"+ >>>>>> "#end"+ >>>>>> "#macro(innerMacro $arg2)$arg1#end"+ >>>>>> >>>>>> "#set($arg1='globalvar')#outerMacro('outermacroparam')"; >>>>>> String eval = evaluate(template); >>>>>> assertEquals(eval, "outermacroparam", eval); >>>>>> >>>>>> } >>>>>> >>>>>> --------------------------------------------------------------------- >>>>>> 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 >>>>> >>>> >>>> --------------------------------------------------------------------- >>>> 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 >>> >> >> --------------------------------------------------------------------- >> 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 > --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@velocity.apache.org For additional commands, e-mail: user-h...@velocity.apache.org
