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https://issues.apache.org/jira/browse/GROOVY-12016?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18081582#comment-18081582
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ASF GitHub Bot commented on GROOVY-12016:
-----------------------------------------
testlens-app[bot] commented on PR #2541:
URL: https://github.com/apache/groovy/pull/2541#issuecomment-4474795066
## ✅ All tests passed ✅
🏷️ Commit: 0f890027beea99f5437ce82506e476228519ea4e
▶️ Tests: 99147 executed
⚪️ Checks: 28/28 completed
---
_Learn more about TestLens at [testlens.app](https://testlens.app)._
> New GDK methods: zipWithNext and groupConsecutive
> -------------------------------------------------
>
> Key: GROOVY-12016
> URL: https://issues.apache.org/jira/browse/GROOVY-12016
> Project: Groovy
> Issue Type: New Feature
> Components: Extension methods
> Reporter: Paul King
> Assignee: Paul King
> Priority: Major
>
> h2. {{zipWithNext}}
> Add a {{zipWithNext}} GDK method returning successive adjacent pairs
> (a sliding window of size 2, step 1), plus an overload taking a
> combiner. Mirrors Kotlin's {{zipWithNext()}} / {{zipWithNext(transform)}}.
> Today this needs the non-obvious, off-by-one-prone {{collate(2, 1, false)}}.
> h3. Proposed signatures
> {code:java}
> List<Tuple2<T,T>> zipWithNext(Iterable<T> self)
> <R> List<R> zipWithNext(Iterable<T> self, BiFunction<? super T,?
> super T,? extends R> combiner)
> Iterator<Tuple2<T,T>> zipWithNext(Iterator<T> self) // lazy
> <R> Iterator<R> zipWithNext(Iterator<T> self, BiFunction<? super T,?
> super T,? extends R> combiner)
> List<Tuple2<T,T>> zipWithNext(T[] self)
> <R> List<R> zipWithNext(T[] self, BiFunction<? super T,? super T,?
> extends R> combiner)
> {code}
> h3. Examples
> {code:groovy}
> [1, 2, 3, 4].zipWithNext() == [new Tuple2(1,2), new Tuple2(2,3),
> new Tuple2(3,4)]
> [1, 2, 3, 4].zipWithNext{ a,b -> b-a } == [1, 1, 1] // pairwise
> deltas
> [3,1,4,1,5].zipWithNext{ a,b -> a<=b }.every() == false // monotonic
> check
> [].zipWithNext() == []
> [42].zipWithNext() == [] // no adjacent
> pair
> {code}
> h3. Notes
> Groovy closures coerce to {{BiFunction}}. Primitive-array overloads
> deferred (Tuple2 boxes anyway).
> h2. {{groupConsecutive}}
> Add a {{groupConsecutive}} GDK method splitting a sequence into maximal
> runs of adjacent "same" elements (order preserved; the same key may
> recur in separate runs). Unlike {{groupBy}} (a {{Map}}, global, loses
> order and run boundaries) there is no native equivalent today.
> h3. Proposed signatures
> {code:java}
> List<List<T>> groupConsecutive(Iterable<T> self)
> // default equality
> <K> List<List<T>> groupConsecutive(Iterable<T> self, Function<? super T,?
> extends K> keyFn) // by derived key
> List<List<T>> groupConsecutive(Iterable<T> self, BiPredicate<? super T,?
> super T> sameRun)
> // + Iterator (lazy) and T[] receiver rows, same trio
> {code}
> h3. Examples
> {code:groovy}
> [1,1,2,2,2,3,1,1].groupConsecutive() == [[1,1],[2,2,2],[3],[1,1]] //
> two separate [1,1] runs
> [1,1L,1.0,2,2].groupConsecutive() == [[1,1L,1.0],[2,2]] //
> number-aware default
> ['apple','avocado','banana'].groupConsecutive{ it[0] } ==
> [['apple','avocado'],['banana']]
> xs.groupConsecutive{ a,b -> Objects.equals(a,b) } //
> opt out to strict .equals()
> 'aaabbbcccd'.toList().groupConsecutive().collect{ [it[0], it.size()] } //
> run-length encoding
> {code}
> h3. Design notes
> * No-arg uses Groovy's number-aware equality ({{coercedEquals}}),
> consistent with {{unique()}} and the set-algebra family (derived from
> the DefaultGroovyMethods source; {{contains}}'s plain-equals is the
> documented anomaly, not the model).
> * Opt out via the {{BiPredicate}} overload: {{Objects.equals}} for
> strict, {{(a <=> b) == 0}} for natural-order/value equivalence,
> {{cmp.compare(a,b)==0}} for a Comparator. A {{Comparator}} overload was
> rejected: a boolean closure silently mis-coerces to it.
> * Arity-disambiguated overloads (0/1/2 params); no closure-arity sniffing.
> * {{dedupeConsecutive}} intentionally NOT included — it is
> {{groupConsecutive()*.first()}} (cf. {{findAll}} with no {{rejectAll}}).
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