Which is okay for small ranges; but creates a huge list for large ones.

:) seems like an easy candidate for optimization , since this is optimized for (reverse @a) is optimized 

perl -le " @f = 1 .. 100_000; for(reverse @f ){ $f=$_; $f==$#f and sca
+lar<> } "

perl -le " @f = 1 .. 100_000; for( @f ){ $f=$_; $f==$#f and scalar<> }
+ "

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In reply to Re^2: counting backward (optimize foreach reverse low .. high by Anonymous Monk
in thread counting backward by ag4ve

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