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<head><title>addHook(HashTable,Thing,Function) -- add a hook function to an object for later processing</title>
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<div><h1>addHook(HashTable,Thing,Function) -- add a hook function to an object for later processing</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>addHook(obj,key,hook)</tt></div>
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<li><span>Function: <a href="_add__Hook.html" title="add a hook function to an object for later processing">addHook</a></span></li>
<li><div class="single">Inputs:<ul><li><span><tt>obj</tt>, <span>a <a href="___Hash__Table.html">hash table</a></span></span></li>
<li><span><tt>key</tt>, <span>a <a href="___Thing.html">thing</a></span></span></li>
<li><span><tt>hook</tt>, <span>a <a href="___Function.html">function</a></span></span></li>
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<li><div class="single">Consequences:<ul><li>the function <tt>hook</tt> is added to the beginning of the list (possibly absent) of hooks stored in <tt>obj#key</tt> if <tt>obj</tt> is mutable, or in <tt>obj.cache#key</tt> if not</li>
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<div class="waystouse"><div class="single"><h2>Code</h2>
<pre>../../m2/methods.m2:489:56-489:125: --source code:
addHook (HashTable,Thing,Function) := (obj,key,hook) -> (c := obj.cache; c#key = if c#?key then prepend(hook,c#key) else {hook})
../../m2/methods.m2:485:63-485:121: --source code:
addHook (MutableHashTable,Thing,Function) := (obj,key,hook) -> obj#key = if obj#?key then prepend(hook,obj#key) else {hook}</pre>
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<div class="single"><h2>See also</h2>
<ul><li><span><a href="_run__Hooks_lp__Hash__Table_cm__Thing_cm__Thing_rp.html" title="run the hook functions stored in an object">runHooks(HashTable,Thing,Thing)</a> -- run the hook functions stored in an object</span></li>
<li><span><a href="_remove__Hook_lp__Hash__Table_cm__Thing_cm__Function_rp.html" title="remove a hook function from an object">removeHook(HashTable,Thing,Function)</a> -- remove a hook function from an object</span></li>
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