[graphic-forms-devel] gfw:append-item API change

Just a heads-up that I intend to change gfw:append-item such that the 'text' and 'image' required arguments will be replaced with a single 'object' argument. Whereas the old arguments were required to be a string and a gfg:image, respectively, the new argument will accept any Lisp object type.

In addition, the gfw:item-manager class, which replaces the old gfw:widget-with-items class, will gain two new slots:

text-provider will hold a function accepting a single argument returning a string

image-provider will hold a function accepting a single argument returning a gfw:image

It's my hope that this will enable greater flexibility for rendering code. I'm borrowing this idea from JFace in the Eclipse framework, which has similar abstractions.