🚀 go-pugleaf

Disclaimer: I have read a lot of postscript code, but written very little.
Excuse my areas of ignorance.

I am interested in a text formatting system written in PostScript.
It would read data from the input stream (similar to the way
the image operator, or any number of image decompression operators
read data from the input stream). Then it would arrange the text
on successive pages and render the text.

i.e. what I'm looking for is troff or TeX or something, but written
in PostScript. Ideally, I would use it like this:

% vi my_file
% cat text_formatter.ps my_file >out_file.ps
% lpr out_file.ps

and my_file would be printed in an attractive format on the printer.
my_file would include text and markup indicating font changes, margins,
etc.

Any ideas?

Dan