[jQuery] recursive dom walker

[AndyCramb]

I am trying to write a plugin that will eventually match a specific
string pattern on the id attribute of all form element(s)
I aim to get a collection of all elements that I want to return for
chaining
I generate a regular expression on the fly based on the arguments
passed in and use this to find an initial set of elements
I have this returning jquery objects using this

        $(":input").filter(function() {
        //return this.id.match(regEx);
            return $(this).attr("id").match(regEx);
        })

this also works

        $(":input").filter(function() {
            return $(this).attr("id").match(regEx);
        }).setDisabled(true);

But when I use this  $("#a_1").recurse({source:"a_1"}).setDisabled
(true); ,my plugin function I get this

TypeError: $("#a_1").recurse is not a function

Its my first attempt at a plugin and I guess I am not returning the
jquery object and I am not sure if this is the correct approach
Anyway any advice would be much appreciated
Full code below

(function($) {

    $.recurse = function(options) {

        var defaults = {
            delimeter: "_"
            , level: 1
            , dir: "down"
            , source: "body"
        }

        var settings = $.extend({}, defaults, options);

        // funtion to find regEx
        function generateRegEx(delimeter, src, direction) {

            console.log(src.split(delimeter));
            console.log(src.length);

            // need to have the concept of next and prev
            // so for prev or back take away a wholePattern match
            // and fro next or forward add a pattern match
            // so based on src and the up or down param
            var dir = direction

            arr = src.split(delimeter);
            var arrLength = arr.length;
            console.log(arrLength);

            if (arrLength <= 1 && direction == "up") {
                //alert("the only way is forward");
                throw Error("you can only go up from here");
                direction = "up";
            }

            arrLength = (direction == "up") ? arrLength - 2 :
arrLength;

            //^([0-9a-zA-Z-]+\_){3}$ - this gets all the pattern does
ntot take account of src
            // supercedes the one above ^a_1(\_[0-9a-zA-Z-]+){2}$
            var delPattern = src + "(\\" + delimeter + "[0-9a-zA-Z-]
+)"; //this will match the character that separates the levels
            var numerOfPattern = "{" + arrLength + "}"; //this matches
all alpha-numeric characters in between the delimeters
            var wholePattern = delPattern + numerOfPattern; // this
combines them both

            console.log(wholePattern);

            var pattern = "^"

            pattern += wholePattern;
            pattern += "$";

            console.log(pattern);
            return new RegExp(pattern);
        };


        var regEx = generateRegEx(settings.delimeter, settings.source,
settings.dir);


        $(":input").filter(function() {
        //return this.id.match(regEx);
            return $(this).attr("id").match(regEx);
        })


    };

})(jQuery);