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NOTE: use Perl; is on undef hiatus. You can read content, but you can't post it. More info will be forthcoming forthcomingly.

All the Perl that's Practical to Extract and Report

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  • Anonymous functions: Generally, if it's a small amount of logic, you can get away with using a lambda. Alternatively, you might be looking for a generator, depending on how you use your anonymous subroutines. A decent example is located here:
    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/361452 [activestate.com]

    Destructors: Destructors are present in Python. Within the class, the __del__(self) method provides this functionality. (Un)Fortunately, it gets called when the object is garbage-collected, so calling del varname removes the variable, not the referred-to object. If the reference count drops to zero, the object will get garbage-collected but you don't have much control. You might be able to call it manually (i.e.: varname.__del__()) but I don't know if that yields any nasty errors or other problems, so I wouldn't advise it. Again, example:
    http://mail.python.org/pipermail/python-list/2000-January/019837.html [python.org]

    Interpolation: Unfortunately, there's not much I can offer up on this. Because of the lack of sigils, it would be difficult to do interpolation reliably. In Python, explicit is better than implicit. So you're basically left with the print "%s %s %d" % var1, var2, var3 idiom. It's not necessarily as convenient as Perl but it's also easy to see what's being used in the string. (Shrugs)

    I'm sorry if I haven't been much help or have repeated what you already knew. If you have questions, please feel free to contact me.
    • Thanks for the reply!

      Generators are almost what I want, but not quite, and the same goes for lambdas. It may just be a matter of programming Python in Python, instead of what I'm doing now. I've used both, but sometimes I just want a coderef. I'd probably mind it less if I didn't feel it was one of the "don't give the programmer sharp tools" decisions (like "let's remove reduce!").

      I know about and use destructors, even in the example. Unfortunately, their use not only occurs at garbage collection, but b
      --
      rjbs
      • My apologies, I should have looked at the code you had written and previous posts first.

        The only thing I don't understand is why the destructors are not being called at the end of the program, as that should not happen. Everything is supposed to be cleaned up at the end.

        You might want to check into the gc module. It provides an interface and debug options for garbage collection. Some doc is located here: http://docs.python.org/lib/module-gc.html [python.org]

        And if I'm still telling you things you know, put me i
        • Wow, the gc module looks like it would be obnoxious to use here, although it could surely do the job!

          I asked on #python (freenode) about this a few days ago, and there was shock and horror at the suggestion of using a destructor to do object cleanup (or anything, for that matter). What the heck?
          --
          rjbs
      • I can understand the difference being a bit uncomfortable, but I eventually got used to using named inner functions in place of anonymous functions. Since the large Python project I worked on started under Python 2.1.x, when the scoping rules were still a bit weak, it was the only way of getting variables shared in closure.

        I guess one of the things that still bugs me about python is the lack of an equivilent to "my". Errors in perl that would be caught at compile time wind up being runtime "UnboundLocal" ex