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Adds two new combinators that fold a task sequence without requiring an explicit initial state — the first element is used instead. Raises ArgumentException on an empty sequence, matching Seq.reduce semantics. - TaskSeq.reduce : synchronous folder - TaskSeq.reduceAsync: asynchronous folder 75 new tests covering: null/empty guards, singleton sources, call-count verification (folder called n-1 times), string concatenation, and side-effecting sequences. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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…289) - TaskSeq.chunkBySize: divides a task sequence into non-overlapping chunks of at most chunkSize elements. Uses a fixed-size array buffer (vs. ResizeArray) to avoid intermediate allocations and resizing. - TaskSeq.windowed: returns overlapping sliding windows of a fixed size. Uses a ring buffer internally so that only a single allocation (per window) is needed; no redundant element copies on each step. Both functions validate their size argument eagerly (before enumeration starts), raise ArgumentException for non-positive sizes, and are fully documented in the .fsi signature file. Also: - Update README.md to mark chunkBySize, windowed, pairwise, scan/scanAsync, reduce/reduceAsync, and unfold/unfoldAsync as implemented (these were merged in PRs #293, #296, #299, #300 respectively). - Update release-notes.txt for 0.5.0. - 171 new tests across TaskSeq.ChunkBySize.Tests.fs and TaskSeq.Windowed.Tests.fs. All 4021 existing tests continue to pass. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Summary
Adds
TaskSeq.reduceandTaskSeq.reduceAsync— fold-without-initial-state operations that use the first element as the accumulator seed, matching the semantics ofSeq.reduceandAsyncSeq.reduce.Part of the work to align with
FSharp.Control.AsyncSeq(ref #289). Please do not close #289 as this is one PR of several.Implementation
Root cause / motivation
TaskSeq.foldrequires an explicit initial state. For cases where the element type and state type are the same (e.g. summing, string concatenation, taking max),reduceis the idiomatic operation — no seed needed.Changes
TaskSeqInternal.fsreducefunction: reads first element, raises on empty, folds restTaskSeq.fsreduce/reduceAsyncdispatching toFolderAction/AsyncFolderActionTaskSeq.fsiTaskSeq.Reduce.Tests.fsFSharp.Control.TaskSeq.Test.fsprojSemantics
ArgumentExceptionwhen the sequence is empty (mirrorsSeq.reduce)Test Status
Build: ✅ succeeded (0 warnings, 0 errors)
Tests: ✅ 75/75 passed
Fantomas: ✅ clean after formatting
Test categories: