Re: Spreadsheet display mode

[Richard Stallman <rms@gnu.org>]

    This isn't quite correct---actions in a cell-mode spreadsheet don't
    inherently cause updates to some other text that actually represents
    the spreadsheet data (i.e. formulas.) That is more like how SES works.
    In contrast, most of the stuff I've done with cell-mode involved cells
    with cl structs in them, each typically having some function-valued
    slots, and different user actions could trigger different functions.

I think you are saying that the base data structure is not text at all,
rather Lisp data, and the only text that is used is the generated
text that you use for the display.  Is that right?

    For example, I wrote a little program that uses cell-mode to display a
    grid of colored squares. You can issue cell-mode commands that tell
    the cell to change its color, etc. Once you've drawn something, you
    can invoke another command to generate a buffer with an XPM version of
    the image, as text. It sounds like what you are suggesting is that
    each editing operation (i.e. color change in a pixel) would result in
    an immediate corresponding update to the XPM text.

I wasn't saying anything about an XPM version of anything.  That isn't
part of what I was talking about.  I was talking about a columnar
mode for Emacs redisplay, which would take the text in the buffers
and put it into columns for display only.

    I can imagine other, similar situations. For example, using cell-mode
    to replace the default display of dired, buffer-list, and other
    interactive-table stuff--- what would the "real text" be, which we
    were supposed to update on every operation, if the spreadsheet
    represents a list of Emacs buffers or external processes?

I don't entirely understand the question.  The dired data is already
represented as text.  I am not sure whether we would want to use the
columnar mode fyr a dired buffer, but if we did, it wouldn't change
anything but the way it appears on the screen.  (The columns might be
aligned, for instance).

     - A user-interface library that can draw fancy spreadsheets and help
    the user interact with grids of arbitrary Lisp objects (insert/delete
    rows/columns and other basic spreadsheet stuff).
     - Applications that use the UI as a front-end (potentially SES,
    org-table, dired etc)
     - A new feature in the display code of Emacs (written in C) that
    makes this all possible. Can you be more specific about this part? It
    sounds a little bit like indirect buffers.

I don't have more specific ideas yet.