It's the scoping of the parentheses around the my assignment that causes the problem.

The parens have nothing to do with it. A 'my' declaration has no effect until the statement after the 'my'. This is, at least in part, so you can do: 

my $x = 2;
{
    my $x = 3 * $x;
    # $x == 6
}
# $x == 2

[download]

As to your question, you can get away with: 

(@$_ = keys %foo) == 1 or die "Got more than one: @$_\n" for \my @v;

[download]

But I'm not sure it is worth it.

- tye        

In reply to Re: Declaring with my, assigning, and testing in same line (scope) by tye
in thread Declaring with my, assigning, and testing in same line by mordibity

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