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Re: [Python-il] Fwd: Perl Vs. Python on Various Points

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  • Shlomi Fish
    ... Hi Beni! Just wanted to thank you for this great post of yours. You ve confirmed my intuition. Regards, Shlomi Fish ... -- ... Shlomi Fish
    Message 1 of 2 , Jul 22, 2009
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      On Wednesday 15 July 2009 12:47:58 Beni Cherniavsky wrote:
      > On Mon, Jul 13, 2009 at 16:19, Roman Gaufman<hackeron@...> wrote:
      > > I didn't tell my "clients" anything - my employer said you can't use
      > > Perl because it doesn't have compiled bytecode, I asked what about
      > > python, it does - they came back to me saying to use it.
      >
      > If you are satisfied with this outcome, more power to you ;-)
      > If want ammunition in favor of Perl:
      > 1. Python bytecode is really easy to decompile, waaay easier than C.
      > Details below.
      > Be careful with stressing this, lest your employer demands C :-\
      > 2. Perl also uses bytecode, it just doesn't spew it into files by default.
      > But it's easy to do - see below.
      >

      Hi Beni!

      Just wanted to thank you for this great post of yours. You've confirmed my
      intuition.

      Regards,

      Shlomi Fish

      > > There are disassemblers and decompilers for just about all compiled
      > > bytecode out there - they show you the virtual machine instructions
      > > used and some reference identifiers. There are also disassemblers and
      > > decompilers for compiled C code, that also show you the machine
      > > instructions being used.
      >
      > Bytecodes tend to use higher-level operations, with well-defined
      > function frames on stack, debug information, and no ugly C-style
      > optimizations (inlining, unrolling, order-changing scheduling, etc.)
      >
      > Also, dynamic languages like Python have almost no information
      > that can be thrown out after compilation (e.g. types). Everything
      > you write is needed for running.
      >
      > > pyc is compiled bytecode - so while you can reverse engineer compiled
      > > bytecode (as you can reverse engineer just about everything) -- you
      > > don't have nesting depths, scope, type - all you have is numeric
      > > codes, numeric addresses and some visible references. It's a little
      > > more than fig-leaf protection.
      >
      > Wrong! Python bytecode retains scopes, variable names, etc.
      > Decompiled python code is really almost identical to original!
      > About the only thing you lost are comments:
      > http://sourceforge.net/projects/decompyle/
      > http://www.crazy-compilers.com/decompyle/
      >
      > You can achieve a bit more protection by obfuscating names:
      > http://pawsense.com/python..obfuscator/
      > http://www.lysator.liu.se/~astrand/projects/pyobfuscate/
      > but these only work on single-module projects and aren't 100% safe.
      >
      > At the very least, use python -OO to produce .pyo without docstrings.
      > Note that -O also discards assert statements
      > (lesson: never use assert for input validation in Python).
      >
      > Perl bytecode
      > -----------------
      > See:
      > http://www.developertutorials.com/tutorials/cgi-perl/optimize-perl-050409/p
      >age10.html http://perldoc.perl.org/B/Bytecode.html
      > http://www.perlmonks.org/?node_id=62936
      > (I never used any of those, just shooting relevant google results.)
      >
      > I don't know how much information Perl bytecode retains;
      > from the little I know about Perl internals, I suspect it loses more
      > details and does more transformations than Python,
      > so decompiled code should looks less like the source.
      > If even more armor is needed, there are obfuscators for Perl too.
      >
      > --
      > Beni <cben@...>
      > _______________________________________________
      > Python-il mailing list
      > Python-il@...
      > http://hamakor.org.il/cgi-bin/mailman/listinfo/python-il

      --
      -----------------------------------------------------------------
      Shlomi Fish http://www.shlomifish.org/
      Parody on "The Fountainhead" - http://xrl.us/bjria

      God gave us two eyes and ten fingers so we will type five times as much as we
      read.
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