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So, in other words, a language needs general recursion in order for library authors to implement map/fold/reduce etc. However, everyday programmers shouldn’t us

• AstralStorm 9y ago
  By that definition a while loop is general recursion. Neither map, fold nor reduce require recursion to implement. All are either for or while loops and this is how the actual computer is going to execute them. Our Von Neumann machines execute lists of instructions and not functions. They are inherently stateful.
• vanderZwan 9y ago
  If-statements and all loops are all some form of "jump if zero/not zero" at the assembly level - so you could (and under the hood have to) implement all control structures used in higher level languages with conditional gotos, and probably even come up with a few more exotic control structures that might be better in rare situations. But despite that flexibility we prefer to use the abstractions we're familiar with, as it makes it much easier to reason about the code (when you're using when you read a for loop or an if statement you know what it does, you don't have to spend extra time figuring out what a particular conditional goto construction does). The idea is that plain recursion is like goto: a fundamental building block to the implementation, but not the abstraction level you want to work with if you can avoid it.