translate a string path to a namespaced var value

// Function to convert the schema's fields into walk paths
var buildPath = function (needle) {
    var path = null, keys = [], i = 0;

    if (needle) {
        // Strip the ["string keys"] and [1] array indexes
        needle = needle.
            replace(/\[(['"])(.*?)\1\]/g,
                function (x,$1,$2) {
                    keys[i]=$2;
                    return '.@'+(i++);
                }).
            replace(/\[(\d+)\]/g,
                function (x,$1) {
                    keys[i]=parseInt($1,10)|0;
                    return '.@'+(i++);
                }).replace(/^\./,''); // remove leading dot 

        // If the cleaned needle contains invalid characters, the 
        // path is invalid
        if (!/[^\w\.\$@]/.test(needle)) {
            path = needle.split('.');
            for (i=path.length-1; i >= 0; --i) {
                if (path[i].charAt(0) === '@') {
                    path[i] = keys[parseInt(path[i].substr(1),10)];
                }   
            }   
        } else {
            YAHOO.log("Invalid locator: " + needle, "error", this.toString());
        }
    }
       
    return path;
};      
    
// Function to walk a path and return the pot of gold
var walkPath = function (path, origin) {
    var v = origin || window,
        i = 0,
        len = path.length;

    for (; i < len && v; ++i) {
        v = v[path[i]];
    }

    return v;
};