[Repo Assist] Add AsyncSeq.tryFindBack, findBack, tryFindBackAsync, findBackAsync#294
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[Repo Assist] Add AsyncSeq.tryFindBack, findBack, tryFindBackAsync, findBackAsync#294github-actions[bot] wants to merge 2 commits intomainfrom
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Adds four new functions mirroring Array.findBack / List.findBack from the F# standard library: - tryFindBackAsync: returns the last element satisfying an async predicate, or None - tryFindBack: synchronous predicate variant of the above - findBackAsync: like tryFindBackAsync but raises KeyNotFoundException - findBack: like tryFindBack but raises KeyNotFoundException Implementation scans the entire sequence, keeping track of the last matching element. 10 new tests added; all 382 tests pass. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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🤖 This PR was created by Repo Assist, an automated AI assistant.
Adds four new functions mirroring
Array.findBack/List.findBackfrom the F# standard library:tryFindBackAsyncNoneif none foundtryFindBackNoneif none foundfindBackAsynctryFindBackAsyncbut raisesKeyNotFoundExceptionwhen no element is foundfindBacktryFindBackbut raisesKeyNotFoundExceptionwhen no element is foundImplementation
Each function scans the entire sequence from front to back, tracking the last element that satisfied the predicate. This is the correct approach since async sequences are not randomly accessible and cannot be reversed without materialisation.
The async-predicate variants (
tryFindBackAsync,findBackAsync) use a direct enumerator loop. The sync-predicate variants delegate to their async counterparts viapredicate >> async.Return.findBack/findBackAsyncdelegate totryFindBack/tryFindBackAsyncand raise onNone.Changes
src/FSharp.Control.AsyncSeq/AsyncSeq.fs— 4 new function implementationssrc/FSharp.Control.AsyncSeq/AsyncSeq.fsi— 4 new public signatures with XML-doctests/FSharp.Control.AsyncSeq.Tests/AsyncSeqTests.fs— 10 new testsRELEASE_NOTES.md— updated 4.11.0 entryTest Status
✅ Build succeeded (0 errors, pre-existing warnings only — FS9999 for
groupByAsync).✅ All 382 tests pass — 10 new, 372 pre-existing.