Why do lt and gt in Perl not work for comparing real numbers?

Question

Lets examine the following perl code

if ($a lt 0.00 or $a gt 100.000)
{
    print "a must be between 0 and 100 \n";
    exit 1
}
exit 0

Lets say a equals 5. The above code will exit with failure status because a isn't between 0 and 100.

Simply replacing the lt and gt with the actual operators they represent, < and > respectively, yields the expected results. Replacing the 100 with a number starting with a 9 will also yield the expected result.

Why are Perl's comparison operators telling me 5 is not between 0 and 100?

Answer 1

lt and gt are string operators, with numbers you want to use plain old < and >. Perl is polymorphic on values, so it's monomorphic on operators (unlike for example python which is the other way around).