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<head><title>stashValue -- stash values of functions in their arguments</title>
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<div><h1>stashValue -- stash values of functions in their arguments</h1>
<div class="single"><h2>Synopsis</h2>
<ul><li><div class="list"><dl class="element"><dt class="heading">Usage: </dt><dd class="value"><div><tt>((stashValue KEY) f) x</tt></div>
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<li><div class="single">Inputs:<ul><li><span><tt>KEY</tt></span></li>
<li><span><tt>f</tt>, <span>a <a href="___Function.html">function</a></span></span></li>
<li><span><tt>x</tt>, <span>a <a href="___Mutable__Hash__Table.html">mutable hash table</a></span>, an argument for <tt>f</tt></span></li>
</ul>
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</li>
<li><div class="single">Outputs:<ul><li><span>The value of <tt>f x</tt> is returned, but the value is saved in <tt>x#KEY</tt> and not recomputed later. However, if the value found in <tt>x#KEY</tt> is <span>an <a href="___Cache__Function.html">a cache function</a></span>, such as is returned by <tt>(stashValue KEY) f</tt>, then the value of <tt>x#KEY x</tt> is returned instead, after first removing <tt>x#KEY</tt> from <tt>x</tt>.</span></li>
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<div class="single"><h2>Description</h2>
<div><table class="examples"><tr><td><pre>i1 : x = new MutableHashTable from { val => 1000 }
o1 = MutableHashTable{...1...}
o1 : MutableHashTable</pre>
</td></tr>
<tr><td><pre>i2 : f = (t -> (print "hi there"; t.val^4))
o2 = f
o2 : FunctionClosure</pre>
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<tr><td><pre>i3 : h = (stashValue VALUE) f
o3 = {*a cache function*}
o3 : CacheFunction</pre>
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<tr><td><pre>i4 : h x
hi there
o4 = 1000000000000</pre>
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<tr><td><pre>i5 : h x
o5 = 1000000000000</pre>
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<tr><td><pre>i6 : peek x
o6 = MutableHashTable{val => 1000 }
VALUE => 1000000000000</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_cache__Value.html" title="cache values of functions in their arguments">cacheValue</a> -- cache values of functions in their arguments</span></li>
</ul>
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<div class="waystouse"><div class="single"><h2>Code</h2>
<pre>../../m2/methods.m2:516:18-524:26: --source code:
stashValue = key -> f -> new CacheFunction from (x -> (
if x#?key then (
val := x#key;
if class val === CacheFunction then (
remove(x,key);
x#key = val x)
else val
)
else x#key = f x))</pre>
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