That's a good idea, but it requires the language ecosystem to be shipped with that kind of preprocessor. In the given examples (Java and Python), that's not the

That's a good idea, but it requires the language ecosystem to be shipped with that kind of preprocessor. In the given examples (Java and Python), that's not the case. And the proposal fails if you comment out non-compiling code without the context switch to a preprocessor: if false: this(does not compile) else: that.might("be")