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https://issues.apache.org/jira/browse/JEXL-269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16620657#comment-16620657
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Henri Biestro commented on JEXL-269:
------------------------------------
On maps, looping on entries allows explicit access to both the key and the
value per entry.
{code:java}
for(var e : map.entries()) {
var key = e.key;
var value = e.value;
....
}
{code}
A list is not necessarily a RandomAccess collection; the so called iteration
index may only be an iteration counter in the general case. And a counter
should not be used as a general purpose access index the way a key is used in a
map. Besides, the casual
{code:java}
var i = 0;
for(var item : list) { i += 1; ... }
{code} seems an understandable pattern to most coders.
Arguably here again, shortening the syntax does not seem to make the intent
clearer and may be very misleading in terms of performance.
> Indexed for-loop
> ----------------
>
> Key: JEXL-269
> URL: https://issues.apache.org/jira/browse/JEXL-269
> Project: Commons JEXL
> Issue Type: New Feature
> Affects Versions: 3.1
> Environment: I have created a PR for this feature, please see
> [PR#12|https://github.com/apache/commons-jexl/pull/12]
> Reporter: Dmitri Blinov
> Priority: Minor
>
> Introduce new extended syntax of 'for' statement, which allows to specify two
> variables, like the following
> {code:java}
> for (var i, item : list){code}
> Inside the loop, the first variable gets current iteration index, starting
> from 0, and the second variable gets current iterated value. The special
> consideration is taken for iteration over map entries, like the following
> {code:java}
> for(var key, entry : map){code}
> , in this case the first variable is the map key, and the second is the
> corresponding map value
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