[tex-eplain] left equation numbers

[Dan Luecking]

The following exchange took place on comp.text.tex:

 >> ... Is there posibility to make an automatics number?
 >
 >Yes: use the eplain macro package and the \eqdef command:
 >
 >----------------------------------------
 >\input eplain
 >$$\eqalign{Y_0+\cdots+X_p&=m,\cr
 >Y_1+\cdots+Y_q&=n.\cr
 >Y_2+\cdots+Y_q&=n.\cr
 >Y_3+\cdots+Y_q&=n.\cr}\eqdef{a}$$
 >----------------------------------------
 >
 >However, AFAIK it does not allow to put the equation number on the left.

It seems an unusual feature to be missing from eplain.
It seems as simple as changing whether \eqno or \leqno
is performed by \@eqdef.

Perhaps eplain needs a replacement for \eqno/\leqno
(\eqnum?) that would respond to a switch:

   \newif\iflefteqnumbers
   \def\eqnum{%
     \iflefteqnumbers
       \expandafter\leqno
     \else
       \expandafter\eqno
     \fi}

Amstex has a similar switch for its \tag macro. Such a feature
would probably be a useful addition to eplain. Or am I missing
something?


Dan

Daniel H. Luecking
Department of Mathematical Sciences
University of Arkansas
"Dubito ergo cogito, cogito ergo sum" --Descartes