You can write code in any language that fails at runtime depending on the day. What's notable about this is that its _syntactical correctness_ depends on the da

You can write code in any language that fails at runtime depending on the day. What's notable about this is that its _syntactical correctness_ depends on the day, which is not possible to achieve in many languages. What's being noted is the degree of flexibility that Perl has with respect to its execution environment. Though if you include preprocessors, you expand the number of languages for which you can do something similar.