# Functionality
The app/
directory contains all of the theme functionality. Since Sage is a starter theme, it’s okay for you to modify files within app/
to meet the needs of the site you’re building.
The PHP code in Sage is namespaced, so make sure to use namespaced functions and classes (opens new window).
app/setup.php
– Enqueue stylesheets and scripts, register support for theme features withadd_theme_support
, register navigation menus and sidebars. See Theme Configuration and Setup.app/admin.php
– Placeholder code for the WordPress theme customizer. You can also use this file for anything related to the WordPress admin.app/filters.php
– Add WordPress filters in this file. Filters included by default:body_class
– add<body>
classesexcerpt_more
– add "… Continued" to excerptstemplate_include
– enable the theme wrapper- Various filters for the Blade implementation
app/helpers.php
– Helper functions used throughout the theme:asset_path
– used when enqueueing theme assets to provide the correct versioned asset filenamesdisplay_sidebar
– used to control displaying the sidebartitle
– used to return page titles