I like the idea of an intermediary step between textual programming and visual programming. However the author only discusses how the symbols are rendered. What about input methods? I can think of a few options: use keyboard shortcuts, use the mouse, implement some kind of modal editor (vim-like) or a use special keyboard (APL keyboard comes to mind)?
That's simple... to start a string literal, you type a ", and as you type the green box will continue to expand to contain what you're typing until you type another " to end the literal. This is, somehow, better...
Simply render "xxxx" differently and you are about done; e.g. render it as ˹xxxx˼ with some background highlight.
Incremental text input is a different problem. If you only have to deal with a batch renderer, then no change is needed; if you have an interactive IDE, you might want to complete the closing " so feedback remains sane.
