Without experimental features, even. 
my $VALUE  = qr/(?!\.(?![0-9]))(?:$QUOTED|$NUM)/;

[download]
Update: Oh, I see this is tye's solution, as well.
Caution: Contents may have been coded under pressure.

In reply to Re: Forcing a regex to fail by Roy Johnson
in thread Forcing a regex to fail by Ovid

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