Dmitri Blinov created JEXL-251:
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Summary: Safe navigation operator
Key: JEXL-251
URL: https://issues.apache.org/jira/browse/JEXL-251
Project: Commons JEXL
Issue Type: New Feature
Affects Versions: 3.1
Reporter: Dmitri Blinov
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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