Sophie: sbcl-1.0.31-1mdv2010.0 i586

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

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<h3 class="section">5.4 Variable Access</h3>

<p><a name="index-Debug-variables-83"></a><a name="index-Variables_002c-debugger-access-84"></a>
There are two ways to access the current frame's local variables in
the debugger: <samp><span class="command">list-locals</span></samp> and <code>sb-debug:var</code>.

   <p>The debugger doesn't really understand lexical scoping; it has just
one namespace for all the variables in the current stack frame.  If a
symbol is the name of multiple variables in the same function, then
the reference appears ambiguous, even though lexical scoping specifies
which value is visible at any given source location.  If the scopes of
the two variables are not nested, then the debugger can resolve the
ambiguity by observing that only one variable is accessible.

   <p>When there are ambiguous variables, the evaluator assigns each one a
small integer identifier.  The <code>sb-debug:var</code> function uses this
identifier to distinguish between ambiguous variables.  The
<samp><span class="command">list-locals</span></samp> command prints the identifier.  In the
following example, there are two variables named <code>X</code>.  The first
one has identifier 0 (which is not printed), the second one has
identifier 1.

<pre class="example">     X  =  1
     X#1  =  2
</pre>
   <div class="defun">
&mdash; Debugger Command: <b>list-locals</b> [<var>prefix</var>]<var><a name="index-list_002dlocals-85"></a></var><br>
<blockquote><p>This command prints the name and value of all variables in the current
frame whose name has the specified <var>prefix</var>.  <var>prefix</var> may be
a string or a symbol.  If no <var>prefix</var> is given, then all available
variables are printed.  If a variable has a potentially ambiguous
name, then the name is printed with a &ldquo;<code>#</code><var>identifier</var>&rdquo;
suffix, where <var>identifier</var> is the small integer used to make the
name unique. 
</p></blockquote></div>

<div class="defun">
&mdash; Function: <b>sb-debug:var</b><var> name &amp;optional identifier<a name="index-sb_002ddebug_003avar-86"></a></var><br>
<blockquote><p>This function returns the value of the variable in the current frame
with the specified <var>name</var>.  If supplied, <var>identifier</var>
determines which value to return when there are ambiguous variables.

        <p>When <var>name</var> is a symbol, it is interpreted as the symbol name of
the variable, i.e. the package is significant.  If <var>name</var> is an
uninterned symbol (gensym), then return the value of the uninterned
variable with the same name.  If <var>name</var> is a string,
<code>sb-debug:var</code> interprets it as the prefix of a variable name
that must unambiguously complete to the name of a valid variable.

        <p><var>identifier</var> is used to disambiguate the variable name; use
<samp><span class="command">list-locals</span></samp> to find out the identifiers. 
</p></blockquote></div>

<ul class="menu">
<li><a accesskey="1" href="Variable-Value-Availability.html#Variable-Value-Availability">Variable Value Availability</a>
<li><a accesskey="2" href="Note-On-Lexical-Variable-Access.html#Note-On-Lexical-Variable-Access">Note On Lexical Variable Access</a>
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