I thought do BLOCK and eval BLOCK were the same except the last one traps error. But I'm wrong！ 
my @dd = (1..10);  grep { s/\d+/a/ } do {@dd}; print @dd;  # aaaaaaaaa
+a
my @dd = (1..10);  grep { s/\d+/a/ } eval{@dd}; print @dd; # 123456789
+10

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seems 'eval' make a copy but 'do' not, any comment?

In reply to what difference between eval and do ? by Anonymous Monk

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