[jira] [Commented] (JEXL-250) Safe navigation operator

["Henri Biestro (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JEXL-250?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16352946#comment-16352946 ] 

Henri Biestro commented on JEXL-250:
------------------------------------

Committed https://github.com/apache/commons-jexl/commit/dffcc160edaa1be6dbf57095e67596f9a0a89ee9


> Safe navigation operator
> ------------------------
>
>                 Key: JEXL-250
>                 URL: https://issues.apache.org/jira/browse/JEXL-250
>             Project: Commons JEXL
>          Issue Type: New Feature
>    Affects Versions: 3.1
>            Reporter: Dmitri Blinov
>            Assignee: Henri Biestro
>            Priority: Minor
>             Fix For: 3.2
>
>
> It would be more convenient for a script writer to have a kind of safe navigation operator, in the form of, for example, ({{object?.property),}} for null pointer dereferences. I think its quite a common feature of many scripting (and compiled languages) now. The safe operator should work like basic navigation operator for non null values and should short-circuit the entire expression evaluation after encountering null value.
> I see the difference of new operator from the existing lenient mode evaluation in ability to explicitly define places in an expression where {{null}} deference is allowed, for example the expression {code}Order.Customer?.Name{code} defines that each {{Order}} should have a {{Customer}} and only the {{Name}} of the {{Customer}} is optional.
> The difference of new operator from the existing null coalescing {{??}} operator is in its ability to short-circuit evaluation.
> So, safe navigation operator would be a helpful syntaxic sugar which in my opinion does not overlap with an existing functionality.



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