Instead of regexp recipes, you can always perform the addition and catch the exception. The FATAL keyword bellow will elevate the warning to an exception - check $0 to find if one was raised. (Normally, statements like $var = '3a' + 3 are not fatal.) 
my $var = '-.3';

use warnings FATA=> 'numeric';
my $a = eval '$var + 3';
print 'Not a number' if $@;

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In reply to Re: Comparison based on type of value held by variables by ioannis
in thread Comparison based on type of value held by variables by ranjan_jajodia

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