[tex-eplain] boxed formulas

[Juan Mari Alberdi]

Hi,

I have used \eqdef{LABEL} inside \eqalignno. The result is nice, as for
example in

$$\eqalignno{
	1 &= \int_{-\infty}^{+\infty}\rho(x)\,dx, &\eqdef{norm}\cr
	\langle x\rangle &= 
		\int_{-\infty}^{+\infty}x\rho(x)\,dx, &\eqdef{aver}\cr
}$$

Juan