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GNU macro processor

5. Conditionals, loops and recursion

Macros, expanding to plain text, perhaps with arguments, are not quite enough. We would like to have macros expand to different things, based on decisions taken at run-time. E.g., we need some kind of conditionals. Also, we would like to have some kind of loop construct, so we could do something a number of times, or while some condition is true.

5.1 Testing macro definitions		Testing if a macro is defined
5.2 Comparing strings		If-else construct, or multibranch
5.3 Loops and recursion		Loops and recursion in m4