On 12/31/2010 12:51 PM, Cesare Di Mauro wrote:

2010/12/31  <skip <at> pobox.com>

   >> Another example. I can totally remove the variable i, just using the
   >> stack, so a debugger (or, in general, having the tracing enabled)
     >> cannot even find something to change about it.

   Ethan> -1

   Ethan> Debugging is challenging enough as it is -- why would you want to
   Ethan> make it even more difficult?

<snarky>
I don't know.  Maybe he wants his program to run faster.
 </snarky>

:D

"Aggressive" optimizations can be enabled with explicit options, in order to leave normal "debugger-prone" code.

I wish the Python compiler would adopt a strategy of being able to disable optimizations.  I wrote a bug about a "leaky abstraction" optimization messing up coverage testing 2.5 years ago, and it was closed as won't fix: http://bugs.python.org/issue2506.  The debate there centered around, "but that line isn't executed, because it's been optimized away."  It's common in sophisticated compilers (as in, any C compiler) to be able to choose whether you want optimizations for speed, or disabling optimizations for debugging and reasoning about the code.  Python would benefit from the same choice.

--Ned.

 

If you use print statements for the bulk of your debugging (many people do),
unrolling loops doesn't affect your debugging ability.

 Skip

It's a common practice. Also IDEs helps a lot, and advanced interactive shells too (such as DreamPie).

Cesare

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<div>
    On 12/31/2010 12:51 PM, Cesare Di Mauro wrote:
    <blockquote cite="mid:AANLkTimmTOSqc43+qhei=C=p7i8Ry7ufiOZziYMZRpsB <at> mail.gmail.com" type="cite">2010/12/31 &nbsp;<span dir="ltr">&lt;<a moz-do-not-send="true" href="mailto:skip <at> pobox.com">skip <at> pobox.com</a>&gt;</span><br><blockquote class="gmail_quote">
        <div class="im">
<br>
          &nbsp; &nbsp;&gt;&gt; Another example. I can totally remove the variable
          i, just using the<br>
          &nbsp; &nbsp;&gt;&gt; stack, so a debugger (or, in general, having the
          tracing enabled)<br>
          &nbsp; &nbsp; &nbsp;&gt;&gt; cannot even find something to change about it.</div>
      </blockquote>
      <blockquote class="gmail_quote">
        &nbsp; &nbsp;Ethan&gt; -1<br><br>
        &nbsp; &nbsp;Ethan&gt; Debugging is challenging enough as it is -- why
        would you want to<br>
        &nbsp; &nbsp;Ethan&gt; make it even more difficult?<br><br>
        &lt;snarky&gt;<br>
        I don't know. &nbsp;Maybe he wants his program to run faster.<br>
        &nbsp;&lt;/snarky&gt;<br>
</blockquote>
      <div><br></div>
      <div>:D</div>
      <div><br></div>
      <div>"Aggressive" optimizations can be enabled with explicit
        options, in order to leave normal "debugger-prone" code.</div>
    </blockquote>
    I wish the Python compiler would adopt a strategy of being able to
    disable optimizations.&nbsp; I wrote a bug about a "leaky abstraction"
    optimization messing up coverage testing 2.5 years ago, and it was
    closed as won't fix: <a class="moz-txt-link-freetext" href="http://bugs.python.org/issue2506">http://bugs.python.org/issue2506</a>.&nbsp; The debate
    there centered around, "but that line isn't executed, because it's
    been optimized away."&nbsp; It's common in sophisticated compilers (as
    in, any C compiler) to be able to choose whether you want
    optimizations for speed, or disabling optimizations for debugging
    and reasoning about the code.&nbsp; Python would benefit from the same
    choice.<br><br>
    --Ned.<br><blockquote cite="mid:AANLkTimmTOSqc43+qhei=C=p7i8Ry7ufiOZziYMZRpsB <at> mail.gmail.com" type="cite">
      <div>&nbsp;</div>
      <blockquote class="gmail_quote">
        If you use print statements for the bulk of your debugging (many
        people do),<br>
        unrolling loops doesn't affect your debugging ability.<br><br>
        &nbsp;Skip</blockquote>
      <div><br></div>
      <div>It's a common practice. Also IDEs helps a lot, and advanced
        interactive shells too (such as DreamPie).</div>
      <div>
<br>
        Cesare<br>
</div>

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