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<h1><a href="../../">wren</a></h1>
<h2>a classy little scripting language</h2>
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<h2>core classes</h2>
<ul>
<li><a href="bool.html">Bool</a></li>
<li><a href="class.html">Class</a></li>
<li><a href="fiber.html">Fiber</a></li>
<li><a href="fn.html">Fn</a></li>
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<td colspan="2"><h2>core classes</h2></td>
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<li><a href="bool.html">Bool</a></li>
<li><a href="class.html">Class</a></li>
<li><a href="fiber.html">Fiber</a></li>
<li><a href="fn.html">Fn</a></li>
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<h1>Fiber Class</h1>
<p>A lightweight coroutine. <a href="../../concurrency.html">Here</a> is a gentle introduction. </p>
<h2>Static Methods <a href="#static-methods" name="static-methods" class="header-anchor">#</a></h2>
<h3>Fiber.<strong>abort</strong>(message) <a href="#fiber.abort(message)" name="fiber.abort(message)" class="header-anchor">#</a></h3>
<p>Raises a runtime error with the provided message: </p>
<div class="codehilite"><pre><span class="vg">Fiber</span><span class="o">.</span><span class="n">abort</span><span class="p">(</span><span class="s">&quot;Something bad happened.&quot;</span><span class="p">)</span>
</pre></div>
<p>If the message is <code>null</code>, does nothing. </p>
<h3>Fiber.<strong>current</strong> <a href="#fiber.current" name="fiber.current" class="header-anchor">#</a></h3>
<p>The currently executing fiber. </p>
<h3>Fiber.<strong>new</strong>(function) <a href="#fiber.new(function)" name="fiber.new(function)" class="header-anchor">#</a></h3>
<p>Creates a new fiber that executes <code>function</code> in a separate coroutine when the
fiber is run. Does not immediately start running the fiber. </p>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">fiber</span> <span class="o">=</span> <span class="vg">Fiber</span><span class="o">.</span><span class="n">new</span> <span class="p">{</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="s">&quot;I won&#39;t get printed&quot;</span><span class="p">)</span>
<span class="p">}</span>
</pre></div>
<p><code>function</code> must be a function (an actual <a href="fn.html">Fn</a> instance, not just an object
with a <code>call()</code> method) and it may only take zero or one parameters. </p>
<h3>Fiber.<strong>suspend</strong>() <a href="#fiber.suspend()" name="fiber.suspend()" class="header-anchor">#</a></h3>
<p>Pauses the current fiber, and stops the interpreter. Control returns to the
host application. </p>
<p>Typically, you store a reference to the fiber using <code>Fiber.current</code> before
calling this. The fiber can be resumed later by calling or transferring to that
reference. If there are no references to it, it is eventually garbage collected. </p>
<p>Much like <code>yield()</code>, returns the value passed to <code>call()</code> or <code>transfer()</code> when
the fiber is resumed. </p>
<h3>Fiber.<strong>yield</strong>() <a href="#fiber.yield()" name="fiber.yield()" class="header-anchor">#</a></h3>
<p>Pauses the current fiber and transfers control to the parent fiber. &ldquo;Parent&rdquo;
here means the last fiber that was started using <code>call</code> and not <code>transfer</code>. </p>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">fiber</span> <span class="o">=</span> <span class="vg">Fiber</span><span class="o">.</span><span class="n">new</span> <span class="p">{</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="s">&quot;Before yield&quot;</span><span class="p">)</span>
<span class="vg">Fiber</span><span class="o">.</span><span class="n">yield</span><span class="p">()</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="s">&quot;After yield&quot;</span><span class="p">)</span>
<span class="p">}</span>
<span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">()</span> <span class="output">Before yield</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="s">&quot;After call&quot;</span><span class="p">)</span> <span class="output">After call</span>
<span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">()</span> <span class="output">After yield</span>
</pre></div>
<p>When resumed, the parent fiber&rsquo;s <code>call()</code> method returns <code>null</code>. </p>
<p>If a yielded fiber is resumed by calling <code>call()</code> or <code>transfer()</code> with an
argument, <code>yield()</code> returns that value. </p>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">fiber</span> <span class="o">=</span> <span class="vg">Fiber</span><span class="o">.</span><span class="n">new</span> <span class="p">{</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="vg">Fiber</span><span class="o">.</span><span class="n">yield</span><span class="p">())</span> <span class="output">value</span>
<span class="p">}</span>
<span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">()</span> <span class="c1">// Run until the first yield.</span>
<span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">(</span><span class="s">&quot;value&quot;</span><span class="p">)</span> <span class="c1">// Resume the fiber.</span>
</pre></div>
<p>If it was resumed by calling <code>call()</code> or <code>transfer()</code> with no argument, it
returns <code>null</code>. </p>
<p>If there is no parent fiber to return to, this exits the interpreter. This can
be useful to pause execution until the host application wants to resume it
later. </p>
<div class="codehilite"><pre><span class="vg">Fiber</span><span class="o">.</span><span class="n">yield</span><span class="p">()</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="s">&quot;this does not get reached&quot;</span><span class="p">)</span>
</pre></div>
<h3>Fiber.<strong>yield</strong>(value) <a href="#fiber.yield(value)" name="fiber.yield(value)" class="header-anchor">#</a></h3>
<p>Similar to <code>Fiber.yield</code> but provides a value to return to the parent fiber&rsquo;s
<code>call</code>. </p>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">fiber</span> <span class="o">=</span> <span class="vg">Fiber</span><span class="o">.</span><span class="n">new</span> <span class="p">{</span>
<span class="vg">Fiber</span><span class="o">.</span><span class="n">yield</span><span class="p">(</span><span class="s">&quot;value&quot;</span><span class="p">)</span>
<span class="p">}</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">())</span> <span class="output">value</span>
</pre></div>
<h2>Methods <a href="#methods" name="methods" class="header-anchor">#</a></h2>
<h3><strong>call</strong>() <a href="#call()" name="call()" class="header-anchor">#</a></h3>
<p>Starts or resumes the fiber if it is in a paused state. Equivalent to: </p>
<div class="codehilite"><pre><span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">(</span><span class="kc">null</span><span class="p">)</span>
</pre></div>
<h3><strong>call</strong>(value) <a href="#call(value)" name="call(value)" class="header-anchor">#</a></h3>
<p>Start or resumes the fiber if it is in a paused state. If the fiber is being
started for the first time, and its function takes a parameter, <code>value</code> is
passed to it. </p>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">fiber</span> <span class="o">=</span> <span class="vg">Fiber</span><span class="o">.</span><span class="n">new</span> <span class="p">{</span><span class="o">|</span><span class="n">param</span><span class="o">|</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">param</span><span class="p">)</span> <span class="output">begin</span>
<span class="p">}</span>
<span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">(</span><span class="s">&quot;begin&quot;</span><span class="p">)</span>
</pre></div>
<p>If the fiber is being resumed, <code>value</code> becomes the returned value of the fiber&rsquo;s
call to <code>yield</code>. </p>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">fiber</span> <span class="o">=</span> <span class="vg">Fiber</span><span class="o">.</span><span class="n">new</span> <span class="p">{</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="vg">Fiber</span><span class="o">.</span><span class="n">yield</span><span class="p">())</span> <span class="output">resume</span>
<span class="p">}</span>
<span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">()</span>
<span class="n">fiber</span><span class="o">.</span><span class="n">call</span><span class="p">(</span><span class="s">&quot;resume&quot;</span><span class="p">)</span>
</pre></div>
<h3><strong>error</strong> <a href="#error" name="error" class="header-anchor">#</a></h3>
<p>The error message that was passed when aborting the fiber, or <code>null</code> if the
fiber has not been aborted. </p>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">fiber</span> <span class="o">=</span> <span class="vg">Fiber</span><span class="o">.</span><span class="n">new</span> <span class="p">{</span>
<span class="mi">123</span><span class="o">.</span><span class="n">badMethod</span>
<span class="p">}</span>
<span class="n">fiber</span><span class="o">.</span><span class="n">try</span><span class="p">()</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="n">fiber</span><span class="o">.</span><span class="n">error</span><span class="p">)</span> <span class="output">Num does not implement method &#39;badMethod&#39;.</span>
</pre></div>
<h3><strong>isDone</strong> <a href="#isdone" name="isdone" class="header-anchor">#</a></h3>
<p>Whether the fiber&rsquo;s main function has completed and the fiber can no longer be
run. This returns <code>false</code> if the fiber is currently running or has yielded. </p>
<h3><strong>try</strong>() <a href="#try()" name="try()" class="header-anchor">#</a></h3>
<p>Tries to run the fiber. If a runtime error occurs
in the called fiber, the error is captured and is returned as a string. </p>
<div class="codehilite"><pre><span class="k">var</span> <span class="n">fiber</span> <span class="o">=</span> <span class="vg">Fiber</span><span class="o">.</span><span class="n">new</span> <span class="p">{</span>
<span class="mi">123</span><span class="o">.</span><span class="n">badMethod</span>
<span class="p">}</span>
<span class="k">var</span> <span class="n">error</span> <span class="o">=</span> <span class="n">fiber</span><span class="o">.</span><span class="n">try</span><span class="p">()</span>
<span class="vg">System</span><span class="o">.</span><span class="n">print</span><span class="p">(</span><span class="s">&quot;Caught error: &quot;</span> <span class="o">+</span> <span class="n">error</span><span class="p">)</span>
</pre></div>
<p>If the called fiber raises an error, it can no longer be used. </p>
<h3><strong>transfer</strong>() <a href="#transfer()" name="transfer()" class="header-anchor">#</a></h3>
<p><strong>TODO</strong> </p>
<h3><strong>transfer</strong>(value) <a href="#transfer(value)" name="transfer(value)" class="header-anchor">#</a></h3>
<p><strong>TODO</strong> </p>
<h3><strong>transferError</strong>(error) <a href="#transfererror(error)" name="transfererror(error)" class="header-anchor">#</a></h3>
<p><strong>TODO</strong> </p>
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