[ http://issues.apache.org/jira/browse/VELOCITY-186?page=comments#action_12329879 ]
Nathan Bubna commented on VELOCITY-186: --------------------------------------- hmm. i tend to think the following is foolish, but it is not entirely unreasonable... #set( $foo = 'bar' ) do stuff with $foo ## if $tool.newFoo is null we should keep using the old foo, so ignore the error message #set( $foo = $tool.newFoo ) do more stuff with $foo also, there is #foreach (the primary thing discussed at the start of this bug), which IIRC, does not even give an error message if one of the elements is null. it is certain that people have had to cope with this in various ways that may break if we change the default behavior. my vote is still to make this configurable with the current behavior as the default. in 2.0, we can switch the default or drop the old behavior completely. > #set does not allow to assign nulls---cannot it be changed? > ----------------------------------------------------------- > > Key: VELOCITY-186 > URL: http://issues.apache.org/jira/browse/VELOCITY-186 > Project: Velocity > Type: Improvement > Components: Source > Versions: 1.3.1 > Environment: Operating System: All > Platform: All > Reporter: Tomislaw Kitynski > Assignee: Velocity-Dev List > Priority: Minor > Fix For: 1.5 > Attachments: patchfile.txt > > Currently #set does not change $ref if the value is null. To quote manual: > "If > the RHS evaluates to null, it is not assigned to the LHS". It has some > advantages, but well, it has also disadvantages. > In my concrete case, I have #foreach loop, where I list some items. > Unfortunatley, the listing (I mean the output) heavily depends on values of > some fields. Considering I have #foreach $item in $items I have to call > $item.foo or $item.bar every time I need to check if the value is set or not. > Instead I'd prefer to #set ($foo = $item.foo) a.s.o. and to use just $foo in > further processing instead of calling $item getFoo() method all the time--- > it's not only about ease of writting, it's also about the time it takes to > invoke that method, plus the time of what this metod really does (it's not > always just simple return this.foo statement). > Of course I would not like to break the compatibility of the #set behaviour, > but I wonder if would be there a way to actually add the possibility to set > some $ref to null, what would casue #if ($ref) to evaluate as false. > Currently, using #set causes, that if we step on $item.foo that returns null, > we have $ref set to the value of a previous $item. The workaround is to use > $item.foo everywhere, but it's not very comfortable. Can it be done something > about that? Maybe on option in velocity.properties enabling of returning > nulls > or new operator (instead of '=') to assign null values (like ':=' for > example). -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
