Decoupling Macros from Functions

When using macros for API purposes, remember that macros are icing, not the whole cake. If we choose to provide a macro API layer, providing access to the underlying machinery via functions is a great decoupling strategy. This makes our code more convenient for consumers who are likely to have varying requirements and aesthetic considerations, but also for us as we read, test, and maintain our code. All other things being equal, it’s far easier to wrap our minds around functions and macros that do one thing than to understand ones that do many things.

Now that you’ve seen how you can make concise APIs to give users a nice interface on top of your domain-logic functions, we’ll drill down to the lower levels of the language to see how you can build control flow mechanisms on top of lower-level constructs.