For writing your own graphics in text format, I think that PostScript is good; you could then make the output in whatever wanted format (which can be raster or

For writing your own graphics in text format, I think that PostScript is good; you could then make the output in whatever wanted format (which can be raster or vector formats), if you have a driver to do so. But if you want storage of vector graphics as the result, different formats will be needed, and I think that PDF and SVG aren't very good, and neither is PostScript (which is a programming language, not a vector graphics format, although it is a programming language for vector graphics). Ghostscript does not have a SVG output driver, although you could first output to PDF, and then use another program to convert PDF to SVG. If they make SlimSVG or other vector formats, then hopefully a Ghostscript driver for that format could be provided, in order that it would be possible to produce it from PostScript programs. You could then produce SlimSVG or whatever other format using whatever programming languages you wanted, whether PostScript, Haskell, or something else.