[Openmcl-devel] Lisp User Interface LUI
terje at in-progress.com
Fri Jan 9 14:37:51 EST 2009
On Jan 9, 2009, at 6:14 AM, Robert Goldman wrote:
> This approach looks very interesting. A question about pushing it
> further --- in the style sheets, would it be possible to use
> symbolic expressions for some of the attributes (e.g., to compute
> some of the sizes)? I used to use the Garnet constraint-based UI
> toolkit quite a bit, and really came to like it for that reason.
> For example, in laying out Gantt charts, it was handy to be able to
> have ribbons whose dimensions were computed functions of the size
> of the window and the duration of the corresponding activities.
Adding constraints to such a stylesheet would be a natural next step.
However, instead of allowing e.g. Garnet constraints directly in the
stylesheet, it would be advantageous to support a simple syntax for
the most useful constraints and perhaps provide a means for the
developer to extend with additional constraints in the application
and/or interface engine.
For example, rather than allowing expressions in the stylesheet like:
<group width="(* parent.width 1/2)">
allow the stylesheet to contain e.g.
and have a definition elsewhere (perhaps defined in the LISP
application) that interprets this to the equivalent as (*
This keeps the stylesheets reasonably comprehensible for non-
programmers. In addition, it encourages developers to identify the
most useful constraints and their parameters, together with how to
provide these in a syntax understandable for those designing the
-- Terje Norderhaug
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