Custom Text Formatting (Previously: Getting long results in a program)

[komame]

It seems I updated my post while you were writing yours. There are still a few threads to clarify. In my opinion, the entire solution should have 3 functions: ATEXTOUT_P (exported), atextout_p (internal), and TEXTSIZE_P (exported). Each of them only once (only one syntax), with "atextout_p" always called with 9 parameters or a list (with a number of parameters from 7 to 9) assuming GROB is always explicitly specified.

EDIT: I like your idea of simulating error triggering. The implementation of TEXSIZE_P also doesn't seem to be complicated. It can be achieved through simple calculations.