OpenEuphoria

One particular concept, which although it has never been made official is currently supported by the current 4.0 preprocessor handler, is that each preprocessor is given a unique file extension and that the different preprocessors input and output are kept separate from each other.

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So, this particular concept, that of preprocessor separation, where instead of running the same code through multiple preprocessors sequentially to add multiple features, we instead run separate parts of the code of the application through different preprocessors to make use of different features in different parts of the code, allows one to take advantage of multiple preprocessors in a far more practical, and maintainable, way.