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<pre class=code>
<B><FONT COLOR="#0000FF">signature</FONT></B> MLTON_WORLD =
   <B><FONT COLOR="#0000FF">sig</FONT></B>
      <B><FONT COLOR="#A020F0">datatype</FONT></B><B><FONT COLOR="#228B22"> status </FONT></B>=<B><FONT COLOR="#228B22"> <FONT COLOR="#B8860B">Clone</FONT> </FONT></B>|<B><FONT COLOR="#228B22"> <FONT COLOR="#B8860B">Original</FONT>

      </FONT></B><B><FONT COLOR="#A020F0">val</FONT></B> load: string -&gt; 'a
      <B><FONT COLOR="#A020F0">val</FONT></B> save: string -&gt; status
      <B><FONT COLOR="#A020F0">val</FONT></B> saveThread: string * Thread.Runnable.t -&gt; unit
   <B><FONT COLOR="#0000FF">end</FONT></B>
</PRE>
<p>
 
</p>

    <ul>

    <li>
<p>
 <tt>datatype&nbsp;status</tt>  <br>
specifies whether a world is original or restarted (a clone). 
</p>
</li>
    <li class="gap">
<p>
 <tt>load&nbsp;f</tt>  <br>
loads the saved computation from file <tt>f</tt>. 
</p>
</li>
    <li class="gap">
<p>
 <tt>save&nbsp;f</tt>  <br>
saves the entire state of the computation to the file <tt>f</tt>.  The  computation can then be restarted at a later time using  <tt>World.load</tt> or the <tt>load-world</tt>   <a href="RunTimeOptions">runtime option</a>.  The call to <tt>save</tt> in the  original computation returns <tt>Original</tt> and the call in the  restarted world returns <tt>Clone</tt>.  
</p>
</li>
    <li class="gap">
<p>
 <tt>saveThread&nbsp;(f,&nbsp;rt)</tt>  <br>
saves the entire state of the computation to the file <tt>f</tt> that  will resume with thread <tt>rt</tt> upon restart.  
</p>
</li>

    </ul>


<h2 id="head-0f01ed56a1e32a05e5ef96e4d779f34784af9a96">Example</h2>
<p>
Suppose that <tt>save-world.sml</tt> contains the following. 
<pre class=code>
<B><FONT COLOR="#0000FF">open</FONT></B> MLton.World
<B><FONT COLOR="#A020F0">val</FONT></B> _ =
   <B><FONT COLOR="#A020F0">case</FONT></B> save <B><FONT COLOR="#BC8F8F">&quot;world&quot;</FONT></B> <B><FONT COLOR="#A020F0">of</FONT></B>
      Original =&gt; print <B><FONT COLOR="#BC8F8F">&quot;I am the original\n&quot;</FONT></B>
    | Clone =&gt; print <B><FONT COLOR="#BC8F8F">&quot;I am the clone\n&quot;</FONT></B>
</PRE>
 
</p>
<p>
Then, if we compile <tt>save-world.sml</tt> and run it, the <tt>Original</tt> branch will execute, and a file named <tt>world</tt> will be created. 
<pre>% mlton save-world.sml
% save-world
I am the original
</pre>
</p>
<p>
We can then load <tt>world</tt> using the <tt>load-world</tt> <a href="RunTimeOptions">run time option</a>. 
</p>

<pre>% save-world @MLton load-world world --
I am the clone
</pre></div>



<p>
<hr>
Last edited on 2007-08-23 03:46:03 by <span title="c-71-57-91-146.hsd1.il.comcast.net"><a href="MatthewFluet">MatthewFluet</a></span>.
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