Generic function for adding body classes in WordPress

gistfile1.aw

<?php 
function add_body_class( $new_classes ) {
	// Turn the input into an array we can loop through
	if ( !is_array( $new_classes ) )
		$new_classes = explode( ' ', $new_classes );

	add_filter( 'body_class', function( $classes ) use( $new_classes ) {
		foreach( $new_classes as $new_class )
			$classes[] = $new_class;

		return $classes;
	} );
}