Another solution to your direct problem is to put the "grep { } @arr" in parentheses.

Indeed... personally I've never been one to favor the "new" style of only using parens when only absolutely necessary. Precendence rules are tricky (i.e. the && vs. and). By using parens I can at least explicitly tell the compiler what I want (and it helps visually as well, IMHO). I find

open(IN, "foo") || die "...";
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much easier to read than

open IN, "foo" or die "...";
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Michael