This is totally wrong!

It's even documented. Just like @array returns its elements as aliases,

grep returns aliases into the original list

$ perl -MDevel::Peek -e'
    my $x;
    Dump $x;
    Dump $_ for $x;
    Dump grep 1, $x;
    Dump do { $x };
    Dump map $_, $x;
    Dump sub { $x }->();
    Dump eval { $x };
' 2>&1 | grep 'SV ='
SV = NULL(0x0) at 0x814ecdc   # Address of $x
SV = NULL(0x0) at 0x814ecdc   # for  aliases
SV = NULL(0x0) at 0x814ecdc   # grep aliases
SV = NULL(0x0) at 0x814ecdc   # do   aliases
SV = NULL(0x0) at 0x814ed9c   # map  copies
SV = NULL(0x0) at 0x814f7f8   # sub  copies
SV = NULL(0x0) at 0x814ed9c   # eval copies

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In reply to Re^2: Reassigning $_ in loop doesn't stick by ikegami
in thread Reassigning $_ in loop doesn't stick by bennymack

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