Sorry that my previous post was truncated. Here's what I meant to say: Fellow groffers, what do you think of generalizing the application of "mark" and "lineup" in eqn to work in columns and piles as well as in separately displayed equations.
A typical use of mark and lineup is to align = signs in a sequence of equations. If the = signs signify steps of a derivation, the equations should obviously be connected, as in a pile. Displaying them separately, each with its own EQ-EN, spreads them out vertically. One can play with number registers (e.g. PD and DD in -ms) to try to get the pile-like resultts, but it would much cleaner if that could happen for free. There is even a situation that EQ-EN can't handle, but piles could: .EQ L xhortid mark = expression1 .EN .EQ longidentifier lineup = expression2 .EN The marked place doesn't leave room for the subsequent lineup. Piles, being typeset as a whole, would be immune to this trouble. Doug
