function validate() {
		var comments;
		var comment;
		var prevPkg;
		var ast;
		var pkg;
		var i;
		var j;

		comments = source.getAllComments();
		for ( i = 0; i < comments.length; i++ ) {
			comment = comments[ i ];
			if ( contains( comment.value, ORDER_COMMENT ) ) {
				isNamespaceIndex = true;
				break;
			}
		}
		if ( isNamespaceIndex ) {
			for ( j = i; j < comments.length; j++ ) {
				comment = comments[ j ];
				ast = parseJSDoc( comment.value, OPTS );
				pkg = extractPackagePath( ast.tags );
				if ( pkg && prevPkg ) {
					if ( pkg.localeCompare( prevPkg, 'en', OPTS_COMPARE ) < 0 ) {
						report( prevPkg, pkg, comment.loc );
					} else {
						prevPkg = pkg;
					}
				} else if ( pkg ) {
					prevPkg = pkg;
				}
			}
		}
	}
Checks whether program is a namespace `index.js` file and if so, if packages are listed in alphabetical order.

@private