Just to give you some hints what's already there...
Aditya Mahajan
1. Have align support with variable number of columns. a &= b &= c &+ d & &+ e
should be typeset as
a = b = c + d + e
At least this should be possible with \wall and \return (using the "nath" module), like this: #v+ a \wall = b \\ = c \wall + d \\ + e \return\return #v- < 20 lines deleted by Adam Duck >
5. have a splitformula environment that allows
a =& b & + c \\ & + d
to come out as
a = b + c + e (1)
with only one formula number. The formula number should be at the last line or the center of the whole formula, configurable by an option. < 142 lines deleted by Adam Duck >
Again, this is a \wall-\return thingy, but \placeformula places the number vertically centered... #v+ \usemodule[nath] \starttext \placeformula \startformula a \wall = b \\ +c \\ +e \return \stopformula \startformula a \wall = b \\ = c \wall + d \\ +e \return\return \stopformula \stoptext #v- cu, Adam.