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This page is a collection of basic utilities used in the examples on various pages.  See 
    <ul>

    <li>
<p>
 <a href="InfixingOperators">InfixingOperators</a>, and 
</p>
</li>
    <li>
<p>
 <a href="ProductType">ProductType</a> 
</p>
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<p>
for longer discussions on some of these utilities. 
</p>

<pre class=code>
<I><FONT COLOR="#B22222">(* Operator precedence table *)</FONT></I>
<B><FONT COLOR="#A020F0">infix</FONT></B>   8  * / div mod        <I><FONT COLOR="#B22222">(* +1 from Basis Library *)</FONT></I>
<B><FONT COLOR="#A020F0">infix</FONT></B>   7  + - ^              <I><FONT COLOR="#B22222">(* +1 from Basis Library *)</FONT></I>
<B><FONT COLOR="#A020F0">infixr</FONT></B>  6  :: @               <I><FONT COLOR="#B22222">(* +1 from Basis Library *)</FONT></I>
<B><FONT COLOR="#A020F0">infix</FONT></B>   5  = &lt;&gt; &gt; &gt;= &lt; &lt;=     <I><FONT COLOR="#B22222">(* +1 from Basis Library *)</FONT></I>
<B><FONT COLOR="#A020F0">infix</FONT></B>   4  &lt;\ \&gt;
<B><FONT COLOR="#A020F0">infixr</FONT></B>  4  &lt;/ /&gt;
<B><FONT COLOR="#A020F0">infix</FONT></B>   3  o
<B><FONT COLOR="#A020F0">infix</FONT></B>   2  &gt;|
<B><FONT COLOR="#A020F0">infixr</FONT></B>  2  |&lt;
<B><FONT COLOR="#A020F0">infix</FONT></B>   1  :=                 <I><FONT COLOR="#B22222">(* -2 from Basis Library *)</FONT></I>
<B><FONT COLOR="#A020F0">infix</FONT></B>   0  before &amp;

<I><FONT COLOR="#B22222">(* Some basic combinators *)</FONT></I>
<B><FONT COLOR="#A020F0">fun</FONT></B> const x _ = x
<B><FONT COLOR="#A020F0">fun</FONT></B> cross (f, g) (x, y) = (f x, g y)
<B><FONT COLOR="#A020F0">fun</FONT></B> curry f x y = f (x, y)
<B><FONT COLOR="#A020F0">fun</FONT></B> fail e _ = <B><FONT COLOR="#A020F0">raise</FONT></B> e
<B><FONT COLOR="#A020F0">fun</FONT></B> id x = x

<I><FONT COLOR="#B22222">(* Product type *)</FONT></I>
<B><FONT COLOR="#A020F0">datatype</FONT></B><B><FONT COLOR="#228B22"> ('a, 'b) product </FONT></B>=<B><FONT COLOR="#228B22"> <FONT COLOR="#B8860B">&amp;</FONT> <B><FONT COLOR="#A020F0">of</FONT></B> 'a * 'b

<I><FONT COLOR="#B22222">(* Sum type *)</FONT></I>
</FONT></B><B><FONT COLOR="#A020F0">datatype</FONT></B><B><FONT COLOR="#228B22"> ('a, 'b) sum </FONT></B>=<B><FONT COLOR="#228B22"> <FONT COLOR="#B8860B">INL</FONT> <B><FONT COLOR="#A020F0">of</FONT></B> 'a </FONT></B>|<B><FONT COLOR="#228B22"> <FONT COLOR="#B8860B">INR</FONT> <B><FONT COLOR="#A020F0">of</FONT></B> 'b

<I><FONT COLOR="#B22222">(* Some type shorthands *)</FONT></I>
</FONT></B><B><FONT COLOR="#A020F0">type</FONT></B><B><FONT COLOR="#228B22"> 'a uop </FONT></B>=<B><FONT COLOR="#228B22"> 'a -&gt; 'a
</FONT></B><B><FONT COLOR="#A020F0">type</FONT></B><B><FONT COLOR="#228B22"> 'a fix </FONT></B>=<B><FONT COLOR="#228B22"> 'a uop -&gt; 'a
</FONT></B><B><FONT COLOR="#A020F0">type</FONT></B><B><FONT COLOR="#228B22"> 'a thunk </FONT></B>=<B><FONT COLOR="#228B22"> unit -&gt; 'a
</FONT></B><B><FONT COLOR="#A020F0">type</FONT></B><B><FONT COLOR="#228B22"> 'a effect </FONT></B>=<B><FONT COLOR="#228B22"> 'a -&gt; unit
</FONT></B><B><FONT COLOR="#A020F0">type</FONT></B><B><FONT COLOR="#228B22"> ('a, 'b) emb </FONT></B>=<B><FONT COLOR="#228B22"> ('a -&gt; 'b) * ('b -&gt; 'a)

<I><FONT COLOR="#B22222">(* Infixing, sectioning, and application operators *)</FONT></I>
</FONT></B><B><FONT COLOR="#A020F0">fun</FONT></B> x &lt;\ f = <B><FONT COLOR="#A020F0">fn</FONT></B> y =&gt; f (x, y)
<B><FONT COLOR="#A020F0">fun</FONT></B> f \&gt; y = f y
<B><FONT COLOR="#A020F0">fun</FONT></B> f /&gt; y = <B><FONT COLOR="#A020F0">fn</FONT></B> x =&gt; f (x, y)
<B><FONT COLOR="#A020F0">fun</FONT></B> x &lt;/ f = f x

<I><FONT COLOR="#B22222">(* Piping operators *)</FONT></I>
<B><FONT COLOR="#A020F0">val</FONT></B> <B><FONT COLOR="#A020F0">op</FONT></B>&gt;| = <B><FONT COLOR="#A020F0">op</FONT></B>&lt;/
<B><FONT COLOR="#A020F0">val</FONT></B> <B><FONT COLOR="#A020F0">op</FONT></B>|&lt; = <B><FONT COLOR="#A020F0">op</FONT></B>\&gt;
</PRE>
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<p>
<hr>
Last edited on 2006-08-13 14:40:14 by <span title="cs181143070.pp.htv.fi"><a href="VesaKarvonen">VesaKarvonen</a></span>.
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