Modifies the Navigation Menu based on current user capabilities

child_nav_menu_args.php

add_filter( 'wp_nav_menu_args', 'child_nav_menu_args' );
/**
 * Modifies the Navigation Menu based on current user capabilities
 *
 * @uses gbootstrap_nav_args() Sets Genesis Bootstrap Navigation Args for wp_nav_menu().
 * @param  array $args Arguments for wp_nav_menu()
 * @return array $args Modified Arguments for wp_nav_menu()
 * @since 1.0.0
 */
function child_nav_menu_args( $args ) {
	// Make sure we are on the Custom Menu Widget; change '' to whatever theme location you wish to modify.
	// Custom Menu Widget does not have a location
	// Assumes that all other uses of wp_nav_menu() are for properly registered locations.
	if ( '' != $args['theme_location'] ) return;

	// Change this to your menu ids. This can also take menu slugs, or even name.
	$menus = array(
		'administrator' => 3,
		'editor'        => 4,
		'author'        => 7,
		'contributor'   => 8,
		'subscriber'    => 9,
	);
	$current_user = wp_get_current_user();
	
	// Highest cap first
	if ( $current_user->has_cap( 'manage_options' ) )
		$args['menu'] = $menus['administrator'];
	if ( $current_user->has_cap( 'edit_others_posts' ) )
		$args['menu'] = $menus['editor'];
	if ( $current_user->has_cap( 'publish_posts' ) )
		$args['menu'] = $menus['author'];
	if ( $current_user->has_cap( 'edit_posts' ) )
		$args['menu'] = $menus['contributor'];
	if ( $current_user->has_cap( 'read' ) )
		$args['menu'] = $menus['subscriber'];
		
	return $args;
}