I am seeing 3 bullet points there pertinent to this issue and all 3 seem to indicate that being compatible was the intention there, or am I wrong ? The way I read #2 and #3 is that the parent scope should only be available if I explicitly specify the scope I want (parent or topmost or replaced).
* For performance and compatibility these are all off by default, *except* for $foreach. The others may be enabled by setting a velocity property like:macro.provide.scope.control = true * When scopes of the same type are nested make the parent Scope available through the child (e.g. $foreach.parent or $foreach.topmost). * When a Scope reference overrides an existing reference that is not a Scope, make it available through the Scope (e.g. $foreach.replaced). On Mon, Apr 30, 2012 at 3:51 PM, Nathan Bubna <nbu...@gmail.com> wrote: > http://velocity.apache.org/engine/devel/changes-report.html#a1.7 > > On Mon, Apr 30, 2012 at 12:37 PM, Boris Partensky > <boris.parten...@gmail.com> wrote: >> 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 >> > > --------------------------------------------------------------------- > 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
