daxitude

This plugin adds an advanced code editor to the post content box on post.php and post-new.php. A third tab is added alongside Visual and HTML modes and you can toggle between the three.
NOTE: Visual Mode tends to eat up most/all of any special formatting. If you want to use ACE I’d suggest disabling Visual mode completely. You can do this easily yourself under Users -> Your Profile -> ‘Disable the visual editor when writing’. You can also do it for all users and for specific post types only. See the accompanying file no-visual.php for an example.
Not all features work in Internet Explorer v8 and earlier.
This does not work in full screen mode. Yet.
<h4>Features</h4>
<ul>
<li>Syntax highlighting</li>
<li>Tabbing</li>
<li>Line numbers</li>
<li>Auto closing of tags and quotes</li>
<li>Line highlighting</li>
<li>Default theme is TextMate</li>
<li>Fixed-width, soft wrap, adjustable height</li>
<li>Remembers your last used mode and loads it up on initial page view</li>
</ul>
<a href="http://ace.ajax.org/" rel="nofollow ugc">ACE Editor</a> can do quite a bit more. If you have integration ideas, let me hear about it
<h3>Todo</h3>
<ul>
<li>make height of editor consistent when toggling between modes</li>
<li>deal with auto_p? (might help preserve formatting from Visual mode)</li>
<li>make it work in full screen mode</li>
<li>allow users to set their ACE preferences on their profile screen</li>
</ul>

ACE Editor for WP

Adds ACE Editor to the post content editor for syntax-highlighting and more

jesucarr

The main reason for the development of this plugin was the lack of options supporting the HTML5 recommendation, where the code snippets should be tagged with <code>pre</code> followed by <code>code</code>, and optionally a class starting with <code>language-</code> and then our language.
You can use the plugin like this:
<pre><code><pre class="prettyprint"><code class="language-php">
// my code
</code></pre>
</code></pre>
Also very important is that although this plugin loads different files depending on your configuration, it fully supports caching scripts (<a href="https://wordpress.org/extend/plugins/w3-total-cache/" rel="ugc">W3 Total Cache</a>) to concatenate and compress all the css and js, so the impact in performance will be minimum.
<h4>Languages</h4>
This syntax highlighter is based on <a href="http://google-code-prettify.googlecode.com/svn/trunk/README.html" rel="nofollow ugc">Google Code Prettify</a> and should work on a number of languages including C and friends, Java, Python, Bash, SQL, HTML, XML, Javascript, Makefiles, and Rust. It works passably on Ruby, PHP, VB, and Awk and a decent subset of Perl and Ruby, but, because of commenting conventions, doesn’t work on Smalltalk.
Other languages are supported via an extension (plugin options): CSS, SQL, YAML, Visual Basic, Clojure, Scala, Latek (TeX, LaTeX), WikiText, Erlang, Go, Haskell, Lua, OCAML, SML, F#, Nemerle, Protocol Buffers, CHDL (VHDL), XQ (XQuery), Lisp, Scheme, Dart, Llvm, Mumps, Pascal, R, S, RD, TCL
<h4>Styles</h4>
Four different styles are provided, and they can be previewed in the plugin options. They are modified to make sure they don’t clash with any other styles in your theme.
You have also the option to include your custom style.
If you have a style that would like to see included in the option list, just <a href="http://www.frontendmatters.com/contact/" rel="nofollow ugc">contact me</a>, or <a href="https://github.com/jesucarr/wordpress-prettify-code-syntax" rel="nofollow ugc">fork me</a>.
<h4>Notes</h4>
<ul>
<li>
Plugin options are at Settings > Prettify Code Syntax. Have a look at the Screenshots tab to see how it looks like.
</li>
<li>
If you don’t care too much about the HTML5 recommendation, you can skip the <code>language-</code> class. The code always gets detected automatically.
</li>
<li>
It will also work if you only use a <code>pre</code> tag without the <code>code</code> tag (but long lines will be wrapped instead of get horizontal scroll), or if you only use a <code>code</code> tag with the <code>prettyprint</code> class (but if you don’t use <code>pre</code> your spaces/returns won’t be maintained.)
</li>
<li>
Be careful using the Visual Editor tab when inserting code, as some HTML tags will be modified or removed.
</li>
<li>
Using a chaching plugin like W3 Total Cache is highly recommended.
</li>
</ul>
<h4>Demo</h4>
You can find a <a href="http://www.frontendmatters.com/open-source/wordpress-plugins/prettify-code-syntax/" rel="nofollow ugc">front end demo</a> here a the bottom.

Prettify Code Syntax

Code syntax highlighter using Google Prettify, supporting the HTML5 recommendation, and caching plugins.

ACE Editor for WP vs Prettify Code Syntax