Ingo, Interestingly your comment is the first I have received that is not of the form "you can jigger this or that to get the desired effect". And indeed I had over the years used every one of those tricks plus one more: assemble the parts with tbl rather than with an eqn matrix. I thought all of them were more like hand-setting type than recording math.
However, I suspect the real reason that mark/lineup doesn't work within a pile is that it wasn't considered. I see no fundamental difference between aligning on a mark and aligning on any other point such as the center or the right end. The only added complexity I see is that one must keep track of two lengths rather that just one within each line. Doug Date: Wed, 2 May 2018 17:53:17 +0200 From: Ingo Schwarze <schwa...@usta.de> To: Doug McIlroy <d...@cs.dartmouth.edu> Cc: groff@gnu.org Subject: Re: [groff] mark/lineup in eqn You may think that pile/pile/pile and matrix are able to do it and produce the correct indentation inside a single .EQ block, so mark/lineup should also be able to as well. But i fear that misses the crucial point. The reason why pile/pile/pile and matrix work seems to be precisely because the tokens are presented out of order in the source code, column by column, and that is precisely what you do not want to carry over to your proposed mark/lineup semantics.
