• The code you write is more elgant (cleaner) and will be easier to maintain and less likely to contain obscure bugs that are hard to track down.

This isn't always true. In general, recursive solutions tend to be more abstract rather than elegant (Although my definition of elegant is "efficient and concise", which isn't the same as everyone else's definition).

  • Recursion is a memory and resource HOG. It's much more efficient to code the solution using global variables.

I'm not quite sure what you mean here. Recursive subs can use global variables the same way as any sub can. Do you mean to compare recursive vs non-recursive? (i.e. a recursion algorithm implemented with a recursion solution as opposed to being implemented with a pure iterative solution) In general, an iterative solution will be much faster and much easier to work with after it is complete; however, an iterative solution might be much more difficult to write, since a recursion allows you to think more abstractly about a problem.

I guess that in your case, the real questions are:
  1. Is performance a problem and/or goal?
  2. If so, does performance hit outweigh code readability?

With Perl, this is a pretty big deal. Perl needs to save a heck of a lot of stuff on the stack when doing a recursive call, making a recursive algorithm proportionally much, much slower in Perl than in another langauge, say, C (slower than normal, I mean). In my opinion, if you're hitting the "deep recursion" warning, then it is probably a good idea to see if there are some areas that can be done more efficiently by flattening the recursion.

Just my 2 cents, anyways.

In reply to Re: Re: Is deep recursion bad? by jryan
in thread Is deep recursion bad? by ezekiel

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