last(itr) should use Iterators.reverse #43497
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stevengj
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Heh, this PR already happened and then got reverted #43106. |
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I see. |
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As I commented in #42225, we should really default to
first(Iterators.reverse(itr))forlast(itr), rather than defaulting toitr[end], similar to how #34868 implementedlast(itr, n).This way you automatically get
lastfor any iterable object that supports reverse iteration — otherwise,last(itr, n)would work butlast(itr)will fail, which is weird.I put in an
last(a) = a[end]fast path forAbstractArrayandTuple.In principle, this could be a breaking, if an object is indexable but doesn't support reverse iteration, but this seems like it should be uncommon?
PS. Currently,
Cmdsupports iteration and indexing but not reverse iteration, so I added an explicit fix for that type here. I'll make a separate PR that adds reverse iteration forCmd, which is a cleaner fix.