[Repo Assist] feat: add map, filter, iter, exists, forall, toList, toArray to Queue and Deque by github-actions[bot] · Pull Request #241 · fsprojects/FSharpx.Collections

github-actions · 2026-03-10T13:12:22Z

🤖 This PR was created by Repo Assist, an automated AI assistant.

Adds seven commonly used collection functions to the Queue and Deque modules. Partially addresses #152 (Align Collection Module functions with FSharp.Collections).

Changes

New functions (Queue and Deque)

Function	Complexity	Description
`map f q`	O(n)	Transform each element, returning a `Queue`/`Deque`
`filter pred q`	O(n)	Keep only elements satisfying the predicate
`iter f q`	O(n)	Apply a side-effecting function to each element (FIFO order)
`exists pred q`	O(n)	Test whether any element satisfies a predicate
`forall pred q`	O(n)	Test whether all elements satisfy a predicate
`toList q`	O(n)	Convert to list in FIFO order
`toArray q`	O(n)	Convert to array in FIFO order

All functions preserve FIFO element order. Signatures added to .fsi files. 21 new tests added.

Implementation notes

Queue.map directly maps over the internal front and rBack lists, preserving the queue structure without any rebuilding — very efficient.

Queue.filter handles the invariant that front should not be empty for a non-empty queue: if filtering removes all front elements, List.rev rBack becomes the new front.

Deque.map similarly maps directly over both internal lists. Deque.filter is simpler since Deque tolerates an empty front (it falls back to rBack).

exists and forall can check rBack in any order (order only matters for iter, toList, toArray).

Test Status

All 731 tests pass (6 pre-existing ptest skips unrelated to this PR):

Passed! - Failed: 0, Passed: 731, Skipped: 6, Total: 737

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… and Deque modules Adds commonly needed collection functions to Queue and Deque that were present in F# List but missing from these modules. Addresses part of #152 (Align Collection Module functions with FSharp.Collections). New functions for both Queue and Deque: - map : transform each element, returning the same collection type - filter : keep elements matching a predicate - iter : apply a side-effecting function to each element (FIFO order) - exists : test whether any element satisfies a predicate - forall : test whether all elements satisfy a predicate - toList : convert to list in FIFO order - toArray : convert to array in FIFO order All seven functions are O(n) and preserve FIFO element order. 21 new tests added (QueueTest and DequeTest), all passing. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

… tests Adds six new module-level functions to DList, mirroring the functions added to Queue and Deque in #241, and further addressing #152. - DList.map: transforms all elements using a function - DList.filter: retains elements matching a predicate - DList.iter: applies an action to each element in order - DList.exists: short-circuit check if any element matches - DList.forall: short-circuit check if all elements match - DList.toArray: returns elements as an array map and filter are implemented via foldBack so they build a DList directly (preserving the length invariant). iter/exists/forall/toArray delegate to the IEnumerable<'T> implementation for correct short-circuit behaviour. Also adds 21 new tests: 14 unit tests and 7 property-based tests that verify results match standard List/Array equivalents. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Adds FSharp.Collections-aligned collection helpers to Queue and Deque, expanding their module APIs with common traversal/transformation/conversion functions while preserving the collections’ logical ordering.

Changes:

Added toList, toArray, map, filter, iter, exists, forall to Queue and Deque implementations.
Exposed the new functions in the corresponding .fsi signature files.
Added unit tests covering the new APIs (order preservation and basic semantics).

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
`src/FSharpx.Collections/Queue.fs`	Implements the seven new `Queue` module functions.
`src/FSharpx.Collections/Queue.fsi`	Adds public signatures/docs for the new `Queue` functions (also includes spacing/formatting changes).
`src/FSharpx.Collections/Deque.fs`	Implements the seven new `Deque` module functions.
`src/FSharpx.Collections/Deque.fsi`	Adds public signatures/docs for the new `Deque` functions (also includes spacing/formatting changes).
`tests/FSharpx.Collections.Tests/QueueTest.fs`	Adds tests for new `Queue` APIs (FIFO order and basic behavior).
`tests/FSharpx.Collections.Tests/DequeTest.fs`	Adds tests for new `Deque` APIs (order and basic behavior).

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gdziadkiewicz · 2026-03-15T17:48:41Z

src/FSharpx.Collections/Queue.fs

+
+    ///O(n). Returns true if any element of the queue satisfies the given predicate.
+    let exists (predicate: 'T -> bool) (q: Queue<'T>) : bool =
+        List.exists predicate q.front || List.exists predicate q.rBack


src/FSharpx.Collections/Queue.fs

+
+    ///O(n). Returns true if all elements of the queue satisfy the given predicate.
+    let forall (predicate: 'T -> bool) (q: Queue<'T>) : bool =
+        List.forall predicate q.front && List.forall predicate q.rBack


src/FSharpx.Collections/Deque.fs

+        List.exists predicate q.front || List.exists predicate q.rBack
+
+    ///O(n). Returns true if all elements of the deque satisfy the given predicate.
+    let forall (predicate: 'T -> bool) (q: Deque<'T>) : bool =
+        List.forall predicate q.front && List.forall predicate q.rBack


src/FSharpx.Collections/Deque.fs

+        List.exists predicate q.front || List.exists predicate q.rBack
+
+    ///O(n). Returns true if all elements of the deque satisfy the given predicate.
+    let forall (predicate: 'T -> bool) (q: Deque<'T>) : bool =
+        List.forall predicate q.front && List.forall predicate q.rBack


src/FSharpx.Collections/Queue.fsi

+    val (|Cons|Nil|): Queue<'T> -> Choice<('T * Queue<'T>), unit>

    ///O(1). Returns a new queue with the element added to the end. (enqueue)
-    val inline conj : 'T -> Queue<'T> -> Queue<'T>
+    val inline conj: 'T -> Queue<'T> -> Queue<'T>



src/FSharpx.Collections/Deque.fsi

+    val (|Cons|Nil|): Deque<'T> -> Choice<('T * Deque<'T>), unit>

-    val (|Conj|Nil|) : Deque<'T> -> Choice<(Deque<'T> * 'T),unit>
+    val (|Conj|Nil|): Deque<'T> -> Choice<(Deque<'T> * 'T), unit>

    ///O(1). Returns a new deque with the element added to the end.
-    val inline conj : 'T -> Deque<'T> -> Deque<'T>
+    val inline conj: 'T -> Deque<'T> -> Deque<'T>

    ///O(1). Returns a new deque with the element added to the beginning.
-    val inline cons : 'T -> Deque<'T> -> Deque<'T>
+    val inline cons: 'T -> Deque<'T> -> Deque<'T>

    ///O(1). Returns deque of no elements.
    [<GeneralizableValue>]
    val empty<'T> : Deque<'T>

    ///O(n). Applies a function to each element of the deque, threading an accumulator argument through the computation, left to right
-    val fold : ('State -> 'T -> 'State) -> 'State -> Deque<'T> -> 'State
+    val fold: ('State -> 'T -> 'State) -> 'State -> Deque<'T> -> 'State

    ///O(n). Applies a function to each element of the deque, threading an accumulator argument through the computation, right to left
-    val foldBack : ('T -> 'State -> 'State) -> Deque<'T> -> 'State -> 'State
+    val foldBack: ('T -> 'State -> 'State) -> Deque<'T> -> 'State -> 'State



tests/FSharpx.Collections.Tests/DequeTest.fs

+                  let q = Deque.ofSeq [ 1; 2; 3; 4; 5 ]
+                  Expect.equal "filter order" [ 1; 3; 5 ] (Deque.filter (fun x -> x % 2 <> 0) q |> Deque.toList)
+              }
+


github-actions bot added automation repo-assist labels Mar 10, 2026

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[Repo Assist] Monthly Activity 2026-03 #230

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Align Collection Module functions with FSharp.Collections #152

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github-actions bot mentioned this pull request Mar 13, 2026

[Repo Assist] feat: add map, filter, iter, exists, forall, toArray to DList #246

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gdziadkiewicz self-assigned this Mar 14, 2026

gdziadkiewicz requested review from Copilot and gdziadkiewicz and removed request for Copilot March 14, 2026 13:10

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Copilot AI reviewed Mar 14, 2026

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[Repo Assist] feat: add map, filter, iter, exists, forall, toList, toArray to Queue and Deque#241

[Repo Assist] feat: add map, filter, iter, exists, forall, toList, toArray to Queue and Deque#241
github-actions[bot] wants to merge 2 commits intomasterfrom
repo-assist/improve-queue-deque-functions-20260310-abe469ac1b3fa769

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github-actions bot commented Mar 10, 2026

Changes

New functions (Queue and Deque)

Implementation notes

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