[tex-eplain] boxed formulas

[Juan Mari Alberdi]

Hello,

As it was enough for me with the first of the possibilities that Oleg
sent, I have adapted it a little bit

\def\dboxit#1#2{$$\vcenter{\boxit{\hbox{$\displaystyle #1$}}}\eqdef{#2}$$}%

and then use it as

\dboxit{\sum_{i=1}^n a_i = {n(a_l+a_n)\over2}}{sumi}

and it seems it works.

Thank you again,
Juan Mari