Graphics editor that represents everything as code/script/markup?

Graphics editor that represents everything as code/script/markup?

When I'm creating graphics in Photoshop or Illustrator, I often wish my
work was entirely represented by some plain-text format so that I could
dive down and make rapid changes without doing too much work. (For
example: changing the properties of a bunch of text labels at once, or
instancing a similar object several times, or globally changing a color
that applies to multiple objects.) I suppose it would sort of work like a
WYSIWYG web development application, where you would do most of your work
with the UI toolset but dive down into the raw HTML/CSS on occasion.
Postscript seems like a good candidate, but I don't think I've seen
anything that uses it in such a way. Are there any tools like this already
available?
(PaintCode looks similar to what I'm describing, but I don't think it's as
robust as Illustrator for example.)