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Comment by juki | Hacker News Reader

I assume you're thinking about Schemes `(let loop (...) ...)`, but that doesn't exist in Common Lisp. CL:LOOP is a looping macro with its own small DSL.

    (loop :for i :below 5
          :when (evenp i) :collect i)
    ;=> (0 2 4)

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That's a step up from loops with 'goto':

    (prog ((result '())
           (i 0))
      loop
      (when (>= i 5)
        (return (reverse result)))
      (when (evenp i)
        (push i result))
      (incf i)
      (go loop))

tagbody/go is implementation detail of macro expansion though.

prog + goto was two decades one of the main tools for loops in Lisp...

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