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<p>
Node:<a name="Tree-buffer%20How%20to">Tree-buffer How to</a>,
Previous:<a rel=previous accesskey=p href="Do-not-with-tree-buffer.html#Do%20not%20with%20tree-buffer">Do not with tree-buffer</a>,
Up:<a rel=up accesskey=u href="tree-buffer.html#tree-buffer">tree-buffer</a>
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<h4>How to deal with certain programming-requirements</h4>
<p>This chapter describes in detail how to solve certain
programming-challenges with tree-buffers.
<h5>Caching the current tree-buffer display</h5>
<p>Sometimes it can be useful or important to cache the current display
of a tree-buffer and display later exactly this cached display-state.
Here is how to do this:
<ol type=1 start=1>
</p><li>Caching the display:
You have to do two tasks: First store the current internal structure
of the tree-buffer; you must do this with the function
<code>tree-buffer-displayed-nodes-copy</code>. Then store the
buffer-contents of that tree-buffer you want to cache; you can do this
for example with <code>buffer-substring</code>. For both tasks you must make
the tree-buffer the current-buffer.
<li>Displaying a previous tree-buffer-cache:
Make the tree-buffer the current buffer, call
<code>tree-buffer-update</code> and pass as second argument <var>CONTENT</var>
the data you have stored in step 1. See the documentation of
<code>tree-buffer-update</code> for details.
<p>Here is an example:
<br><pre>(tree-buffer-update
nil
(cons (nth 2 cache-elem) ;; the stored buffer-string
(nth 1 cache-elem) ;; the stored tree-structure
)))
</pre>
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