Sophie: sbcl-1.0.31-1mdv2010.0 i586

sbcl-1.0.31-1mdv2010.0.i586.rpm

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<h3 class="section">5.2 Debugger Command Loop</h3>

<p>The debugger is an interactive read-eval-print loop much like the
normal top level, but some symbols are interpreted as debugger
commands instead of being evaluated. A debugger command starts with
the symbol name of the command, possibly followed by some arguments on
the same line. Some commands prompt for additional input. Debugger
commands can be abbreviated by any unambiguous prefix: <samp><span class="command">help</span></samp>
can be typed as &lsquo;<samp><span class="samp">h</span></samp>&rsquo;, &lsquo;<samp><span class="samp">he</span></samp>&rsquo;, etc.

   <p>The package is not significant in debugger commands; any symbol with
the name of a debugger command will work. If you want to show the
value of a variable that happens also to be the name of a debugger
command you can wrap the variable in a <code>progn</code> to hide it from
the command loop.

   <p>The debugger prompt is &ldquo;<var>frame</var><code>]</code>&rdquo;, where <var>frame</var> is
the number of the current frame.  Frames are numbered starting from
zero at the top (most recent call), increasing down to the bottom. 
The current frame is the frame that commands refer to.

   <p>It is possible to override the normal printing behaviour in the
debugger by using the <code>sb-ext:*debug-print-variable-alist*</code>.

   <p><a name="Variable-sb_002dext_003a_002adebug_002dprint_002dvariable_002dalist_002a"></a>

<div class="defun">
&mdash; Variable: <b>sb-ext:*debug-print-variable-alist*</b><var><a name="index-sb_002dext_003a_002adebug_002dprint_002dvariable_002dalist_002a-63"></a></var><br>
<blockquote><p><a name="index-sb_002dext_003a_002adebug_002dprint_002dvariable_002dalist_002a-64"></a>an association list describing new bindings for special variables
to be used within the debugger. Eg.

     <pre class="lisp">           ((*PRINT-LENGTH* . 10) (*PRINT-LEVEL* . 6) (*PRINT-PRETTY* . NIL))
</pre>
        <p>The variables in the <code>car</code> positions are bound to the values in the <code>cdr</code>
during the execution of some debug commands. When evaluating arbitrary
expressions in the debugger, the normal values of the printer control
variables are in effect.

        <p>Initially empty, <code>*debug-print-variable-alist*</code> is typically used to
provide bindings for printer control variables. 
</p></blockquote></div>

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