The Syntax WordPress plugin improves the process of inserting and displaying code examples within the WordPress editor.
Preserving the formatting of code within the WordPress editor can be a challenge. This is because WordPress filters content within the editor, which can change the content and/or formatting of the code. The Syntax plugin adds a button to the editor that allows code to be added in a way that preserves the syntax. This is done properly (without the use of shortcodes) so that even if you disable the Syntax plugin in the future, your code will still be wrapped in the semantically correct tags within your posts and pages.
The plugin works by saving each code example both within the editor and in a meta field created by the plugin. Whenever WordPress runs a filter with the potential to modify the code example, the example is copied from the meta field back into the editor.