Function parseModel

* parse directive model to do the array update transform. a[idx] = val => $$a.splice($$idx, 1, val) * * for loop possible cases: * * - test * - test[idx] * - test[test1[idx]] * - test["a"][idx] * - xxx.test[a[a].test1[idx]] * - test.xxx.a["asa"][test1[idx]] *

(val)