[ss2165]

Add array swap and fill methods, plus in-place left and right rotations supporting linear elements. Signed rotation amounts wrap modulo the array length; negative amounts rotate in the opposite direction. Empty arrays are unchanged.

Closes #2481

[codecov-commenter]

Codecov Report

❌ Patch coverage is 43.90244% with 23 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.76%. Comparing base (d7494c5) to head (a334a0f).

Files with missing lines	Patch %	Lines
guppylang/src/guppylang/std/array.py	43.90%	23 Missing ⚠️

Additional details and impacted files

@@                    Coverage Diff                    @@
##           codex/array-structure    #2515      +/-   ##
=========================================================
- Coverage                  92.88%   92.76%   -0.12%     
=========================================================
  Files                        167      167              
  Lines                      17302    17343      +41     
=========================================================
+ Hits                       16071    16089      +18     
- Misses                      1231     1254      +23     

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[github-actions]

Bencher Report

Project	guppylang
Branch	codex/array-mutation
Testbed	Linux

Click to view all benchmark results

Benchmark	hugr_bytes	Benchmark Result bytes x 1e3 (Result Δ%)	Upper Boundary bytes x 1e3 (Limit %)	hugr_nodes	Benchmark Result nodes (Result Δ%)	Upper Boundary nodes (Limit %)
tests/benchmarks/test_big_array.py::test_big_array_compile	📈 view plot 🚷 view threshold	59.84 x 1e3 (0.00%) Baseline: 59.84 x 1e3	60.44 x 1e3 (99.01%)	📈 view plot 🚷 view threshold	4,514.00 (0.00%) Baseline: 4,514.00	4,559.14 (99.01%)
tests/benchmarks/test_ctrl_flow.py::test_many_ctrl_flow_compile	📈 view plot 🚷 view threshold	26.87 x 1e3 (0.00%) Baseline: 26.87 x 1e3	27.14 x 1e3 (99.01%)	📈 view plot 🚷 view threshold	1,182.00 (0.00%) Baseline: 1,182.00	1,193.82 (99.01%)
tests/benchmarks/test_queue_push_pop.py::test_queue_push_benchmark_compile	📈 view plot 🚷 view threshold	6.70 x 1e3 (0.00%) Baseline: 6.70 x 1e3	6.77 x 1e3 (99.01%)	📈 view plot 🚷 view threshold	279.00 (0.00%) Baseline: 279.00	281.79 (99.01%)
tests/benchmarks/test_queue_push_pop.py::test_queue_push_pop_benchmark_compile	📈 view plot 🚷 view threshold	9.22 x 1e3 (0.00%) Baseline: 9.22 x 1e3	9.31 x 1e3 (99.01%)	📈 view plot 🚷 view threshold	371.00 (0.00%) Baseline: 371.00	374.71 (99.01%)

🐰 View full continuous benchmarking report in Bencher

[codspeed]

Merging this PR will not alter performance

1 warning

⚠️ 7 benchmarks are dominated by system calls

System calls cannot be simulated consistently and are left out of the measure. The reported value understates the real cost. Switch to the Walltime instrument to measure them.

Learn more about system calls

See affected benchmarks

✅ 11 untouched benchmarks

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_{Comparing codex/array-mutation (a334a0f) with codex/array-structure (d7494c5)}

[Copilot]

🟡 Changes recommended

Rotation accepts amounts above the array length despite issue #2481 requiring 0 ≤ k ≤ n, leaving a contract conflict that must be reconciled.

1 open issue

• Resolve conflict between rotation bounds and wrapping semantics · New

What changed in this PR

Adds array mutation and in-place rotation utilities to the standard library, addressing #2481 while preserving support for linear elements.

Changes:

• Adds swap and fill methods, retaining existing swap and reverse operations.
• Implements left and right rotations using three reversals, with nonnegative amounts wrapping modulo array length.
• Adds integration tests for mutation results, linear elements, empty arrays, and invalid inputs.

File	Description
tests/​integration/​test_array_mutation.py	Tests mutations, rotations, linear-element preservation, and error handling.
guppylang/​src/​guppylang/​std/​array.py	Adds mutation methods, rotation helpers, and API documentation.

_{Review effort: Balanced}