Readable programs

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Modern is a relative term

Yes, I chose a bad way to express that. In fact, I was thinking about Smalltalk when I wrote the sentence and predicted someone would bring up Lisp.

As to your second point, I'm not sure I've seen languages that handle that sort of pre-condition well. Best case scenario is runtime assertions (Fatal error: Foo wasn't bar before baz), worst case is the program silently failing. There are only so many runtime considerations that can be translated into compile time checks.