RE: DrScheme as Emacs-like kitchen sink

[Greg Pettyjohn <GregP@bsquare.com>]

As long as we're wish-listing for DrScheme, I thought
I'd add my own vapour-ware to the mix:

To make it more convenient to browse large Scheme files,
it would be nice if you could take advantage of the natural
hierarchical nature of s-expressions in order to collapse/expand
your code, like a tree-widget, but right on the page.

This is exactly the way that Internet Explorer *displays* XML,
but without being an editor.

For example consider the following Scheme code:

(define rev-append
  (lambda (ls1 ls2)
    (if (null? ls1)
        ls2
        (rev-append (cdr ls1) (cons (car ls1) ls2)))))

Imagine that the editor could be configured to insert a '+' widget
into strategic locations in the code:

(define rev-append
  ([+]...)) ; here the "[+]" is just text representation of a hypothetical
[+]-widget.

When you clicked on the "[+]" it would change to a "[-]" and
expand out the expression:

(define rev-append
  ([-]lambda (ls1 ls2)
    (if (null? ls1)
        ls2
        (rev-append (cdr ls1) (cons (car ls1) ls2)))))



(The widget would, of course, only be a feature of the editor and
would not add anything to the real code.)

"Strategic locations" for the [+]-widget might be, for example,
the list following the symbol in a define, or analogous
clause in a letrec.

In fact, you could use the pattern matching stuff to make
it easily customizable...


Cheers.