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https://issues.apache.org/jira/browse/JEXL-287?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dmitri Blinov updated JEXL-287:
-------------------------------
Description:
Consider the following example
{code:java}
x = 1; if (false) var x = 2; x
{code}
In this example the {{null}} is returned, which is the value of uninitialized
local variable {{x}}. The expected behaviour is to return {{1.}}
The reason is the variable declaration is a *statement*, so one can expect
that, as a statement, it should be evaluated according to its position within
the script structure.
The suggestion is to move the {{Scope.declareVariable()}} call from parse time
to interpretation time. Also, the resolution whether an identifier inside the
script referes to the local variable or to the contextual variable should be
moved from parse time to the interpretation time.
I think we can also reconsider the variable resolution during a variable
initialization:
{code:java}
sum = 0; var sum = sum + 1{code}
As of now, Jexl evaluates the local variable {{sum}} as {{1}}, as it considers
the {{sum+1}} an expression referencing the local variable {{sum}}, which is,
sort of, pointless. We can change this to referencing a contextual variable
instead, so that the result would be {{2}}. It can be useful in plain-vanilla
Jexl (without an access differentiator between local and contextual variables)
to allow one to initialize a local variable {{foo}} with the value of
contextual variable {{foo}} without using temporary variable.
was:
Consider the following example
{code:java}
x = 1; if (false) var x = 2; x
{code}
In this example the {{null}} is returned, which is the value of uninitialized
local variable {{x}}. The expected behaviour is to return {{1}}
> Wrong resolution of local variables
> -----------------------------------
>
> Key: JEXL-287
> URL: https://issues.apache.org/jira/browse/JEXL-287
> Project: Commons JEXL
> Issue Type: Bug
> Affects Versions: 3.1
> Reporter: Dmitri Blinov
> Priority: Major
>
> Consider the following example
> {code:java}
> x = 1; if (false) var x = 2; x
> {code}
> In this example the {{null}} is returned, which is the value of uninitialized
> local variable {{x}}. The expected behaviour is to return {{1.}}
> The reason is the variable declaration is a *statement*, so one can expect
> that, as a statement, it should be evaluated according to its position within
> the script structure.
> The suggestion is to move the {{Scope.declareVariable()}} call from parse
> time to interpretation time. Also, the resolution whether an identifier
> inside the script referes to the local variable or to the contextual variable
> should be moved from parse time to the interpretation time.
> I think we can also reconsider the variable resolution during a variable
> initialization:
> {code:java}
> sum = 0; var sum = sum + 1{code}
> As of now, Jexl evaluates the local variable {{sum}} as {{1}}, as it
> considers the {{sum+1}} an expression referencing the local variable {{sum}},
> which is, sort of, pointless. We can change this to referencing a contextual
> variable instead, so that the result would be {{2}}. It can be useful in
> plain-vanilla Jexl (without an access differentiator between local and
> contextual variables) to allow one to initialize a local variable {{foo}}
> with the value of contextual variable {{foo}} without using temporary
> variable.
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