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https://issues.apache.org/jira/browse/FLEX-35075?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15237708#comment-15237708
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Alex Harui commented on FLEX-35075:
-----------------------------------
I haven't really taken the time to understand the allowed syntax for e4x
filters. It is rather strange that there is an implied node when evaluating
the expression (that just "year" is allowed instead of "node.year"). This
makes the compiler have to make some assumptions when resolving identifiers
(could 'year' be a global or scope variable?). I'm putting in a fix to get
this simple "year == '2016'" to generate node.child('year') == '2016' for now.
I want to see what other filters people have actually used. It may not be
practical to map all operators to function calls. There might be other complex
expressions that don't easily map. If toString() is implied and we can just
try to insert attribute() and child() calls and let JS run the rest of the
expression, I think that would be easier for the compiler.
> E4X filters need to be smarter
> ------------------------------
>
> Key: FLEX-35075
> URL: https://issues.apache.org/jira/browse/FLEX-35075
> Project: Apache Flex
> Issue Type: Bug
> Components: FalconJX
> Affects Versions: Apache FalconJX 0.6.0
> Reporter: Harbs
>
> The following expression:
> {code:actionscript}
> xmlSource.Set1.child.(year == "2015");
> {code}
> compiles into:
> {code:javascript}
> xmlSource.child('Set1').child('child').filter(function(node){return
> (node.year == "2015")});
> {code}
> This is all fine except for the filter expression.
> node.year means nothing in Javascript.
> I'm not sure the best way to compile this. The following will work, but it
> will probably get tricky covering all cases:
> {code:javascript}
> xmlSource.child('Set1').child('child').filter(function(node){return
> (node.child("year").toString() == "2015")});
> {code}
> What might make more sense might be to add some helper functions like:
> XML.isEqual(randomObject); (mapped to ==)
> XML.isNotEqual(randomObject); (mapped to !=)
> XML.greaterThan(randomObject); (mapped to >)
> XML.lessThan(randomObject); (mapped to <)
> XML.greaterThanOrEqualTo(randomObject);(mapped to >=)
> XML.lessThanOrEqualTo(randomObject);(mapped to <=)
> And the code will figure out the best way to handle these comparisons based
> on the type at runtime.
> In that case, this would compile like this:
> xmlSource.child('Set1').child('child').filter(function(node){return
> (node.child("year").isEqualTo("2015"))});
> Thoughts?
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