A common need will be for guidance on how to nest forms, e.g. a button_to_function form within a form_for such that the nested form will transmit the parent form's parameters to the controller along with its own. This will enable, e.g. checkbox arrays to accompany text entry data such as file paths using techniques more dynamic than just an ad-hoc text_field_tag.
Feel free to add in docrails, if you can.
I'm thinking now that one or another RoR SDK will support this sort of thing. If so then one could use the SDK to nest forms in various ways and then study the code it generates. One always has to drop back into manual mode, after all, to polish, fine-tune and sometimes to clean up after the SDK. I end up using them for a week or two just to get the basic layout and then drop back into manual mode for most of the ongoing work.
@vijaydev can we close this one?