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<h3>Parent</h3>
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<li ><a href="#method-i-5B-5D">#[]</a>
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<h1 id="class-IRB::History" class="class">
class IRB::History
</h1>
<section class="description">
<p>Represents history of results of previously evaluated commands.</p>
<p>Available via <code>__</code> variable, only if <code>IRB.conf[:EVAL_HISTORY]</code> or <code>IRB::CurrentContext().eval_history</code> is non-nil integer value (by default it is <code>nil</code>).</p>
<p>Example (in `irb`):</p>
<pre class="ruby"><span class="ruby-comment"># Initialize history</span>
<span class="ruby-constant">IRB</span><span class="ruby-operator">::</span><span class="ruby-constant">CurrentContext</span>().<span class="ruby-identifier">eval_history</span> = <span class="ruby-value">10</span>
<span class="ruby-comment"># => 10</span>
<span class="ruby-comment"># Perform some commands...</span>
<span class="ruby-value">1</span> <span class="ruby-operator">+</span> <span class="ruby-value">2</span>
<span class="ruby-comment"># => 3</span>
<span class="ruby-identifier">puts</span> <span class="ruby-string">'x'</span>
<span class="ruby-comment"># x</span>
<span class="ruby-comment"># => nil</span>
<span class="ruby-identifier">raise</span> <span class="ruby-constant">RuntimeError</span>
<span class="ruby-comment"># ...error raised</span>
<span class="ruby-comment"># Inspect history (format is "<item number> <evaluated value>":</span>
<span class="ruby-identifier">__</span>
<span class="ruby-comment"># => 1 10</span>
<span class="ruby-comment"># 2 3</span>
<span class="ruby-comment"># 3 nil</span>
<span class="ruby-identifier">__</span>[<span class="ruby-value">1</span>]
<span class="ruby-comment"># => 10</span>
</pre>
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<h3>Public Instance Methods</h3>
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<div id="method-i-5B-5D" class="method-detail ">
<div class="method-heading">
<span class="method-name">[]</span><span
class="method-args">(idx)</span>
<span class="method-click-advice">click to toggle source</span>
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<div class="method-description">
<p>Get one item of the content (both positive and negative indexes work).</p>
<div class="method-source-code" id="5B-5D-source">
<pre><span class="ruby-comment"># File lib/irb/ext/history.rb, line 113</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">[]</span>(<span class="ruby-identifier">idx</span>)
<span class="ruby-keyword">begin</span>
<span class="ruby-keyword">if</span> <span class="ruby-identifier">idx</span> <span class="ruby-operator">>=</span> <span class="ruby-value">0</span>
<span class="ruby-ivar">@contents</span>.<span class="ruby-identifier">find</span>{<span class="ruby-operator">|</span><span class="ruby-identifier">no</span>, <span class="ruby-identifier">val</span><span class="ruby-operator">|</span> <span class="ruby-identifier">no</span> <span class="ruby-operator">==</span> <span class="ruby-identifier">idx</span>}[<span class="ruby-value">1</span>]
<span class="ruby-keyword">else</span>
<span class="ruby-ivar">@contents</span>[<span class="ruby-identifier">idx</span>][<span class="ruby-value">1</span>]
<span class="ruby-keyword">end</span>
<span class="ruby-keyword">rescue</span> <span class="ruby-constant">NameError</span>
<span class="ruby-keyword">nil</span>
<span class="ruby-keyword">end</span>
<span class="ruby-keyword">end</span></pre>
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