Since you mention Forth, I might mention that PostScript is another stack-based programming language (different than Forth although there are some similarities)

Since you mention Forth, I might mention that PostScript is another stack-based programming language (different than Forth although there are some similarities), which can be used to make PDF output. Additional PostScript codes could be made which you can load into your file in order to add additional procedures, etc for doing formatting that you will not need to write by yourself.