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Adds the two mutating shrink operations to dynamic-extent span: - remove_prefix(n): drops the first n elements - remove_suffix(n): drops the last n elements Both are gated to dynamic_extent only via the same SFINAE pattern the default constructor uses. Fixed-extent spans carry their size in the type, so an in-place size mutation isn't representable - matching string_view (no fixed extent) and Abseil's Span (dynamic only). Eight new tests cover n=0, partial shrink, full shrink to empty, both operations combined, and a detection-idiom check confirming fixed-extent spans do not expose these methods. Fixes #3
JeffGarland
reviewed
Apr 26, 2026
JeffGarland
requested changes
Apr 26, 2026
JeffGarland
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Apr 26, 2026
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Also, I don't know how you want to handle this -- fine as another issue, but the readme/examples should be updated to highlight the new features |
Addresses Jeff's review feedback on PR #8: Beman targets C++20 as baseline, so the new modifiers should use a requires clause rather than the SFINAE-style enable_if_t shim. Behavior is identical (the existing void_t-based detection tests still pass), just clearer at the point of declaration. Also picks up the clang-format pass over the at() tests carried in via the merge of main.
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coverage: 100.0%. remained the same — remove-prefix-suffix-p3729 into main |
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Adds the two in-place shrink operations from P3729 — same shape as
string_view's methods and Abseil'sSpan.Both are gated on
Extent == dynamic_extentvia the sameenable_if_ttrick the default constructor already uses. A fixed-extentspan<T, N>carries its size in the type, so an in-place size mutation isn't representable, there is no sensible thing to do for the fixed case, andstring_view(which has no fixed-extent equivalent) sets the precedent.Eight new tests:
n == 0no-op for bothdata()pointer move correctly for prefix; data unchanged for suffix)remove_prefix(size())/remove_suffix(size())both empty the span)bsp::span<int>exposes both methods andbsp::span<int, 3>does notLocal: 53/53 passing.
Fixes #3