> On Feb 23, 2021, at 3:47, M Douglas McIlroy <m.douglas.mcilroy@dartmouth.edu> wrote:
> 
>> I can imagine a simple perl (or python or whatever) script that would run
>> through groff input [and] determine which preprocessors are actually
>> needed ...
> 
> Brian imagined such and implemented it way back when. Though I used
> it, I've forgotten its name. One probably could have fooled it by
> tricks like calling pic only in a .so file and perhaps renaming .so.
> But I never heard of it failing in real life. It does impose an extra
> pass over the input, but may well save a pass compared to the
> defensive groff -pet that I often use or to the rerun necessary when I
> forget to mention some or all of the filters.


If I remember correctly, it was an awk script printing out the
suggested pipeline to use.  One could then cut and paste that line.

	jaap