Of course as far as GUIs are concerned, they provide an interface for "something that does something" as well, so one needs both charachteristics and in fact an OO approach is typically applied, which provides an IMHO excellent approximation to the concept of "describing how something IS also including details about the parts of it that DO something".
However I have the impression that there's still "too much" to it. Granted, GUIs are intrinsically some order of complexity above textual IO, but I think that letting the language have intrinsic markup language(-like) features may make things much easier from the huffmanization POV in these regards.
Now what I'm thinking about is a means of specifiying, say, "portions" in the source that ARE (something). By default they won't be executed at all, but they may provide useful hooks for a suitable module to assign a meaning to them, and of course they should also provide the link with "code that does something" (e.g. callbacks et similia).
Of course I began talking about GUIs, but I wouldn't like to restrict everything to this particular aspect. Perl(6) is supposed to be a mutiparadigmatic language with means to be specialized and "strenghtened" into any of the supported paradigms. So I cannot see why a priori the markup language pardigm shouldn't fit in this picture. HOW to do it (efficiently/elegantly, etc.) is a whole another story...
[1] Although this varies from language to language. If you come to think of TeX and its macro language you can see how approximative this claim is.
Michele --
A question out of curiousity: who is this Green of Green's functions? Is he the same person of Green's theorem? :)
Yes. He was also an early environmentalist; hence the current phrases "green" this and "green" that... - David C. Ullrich in sci.math, thread "Who is Green?"
