On 2012-11-01, Barton Willis <willisb at unk.edu> wrote:
> The rhs of something that isn't an equation is 0; the lhs of
> something that isn't an equation is itself.
Well, rhs/lhs were extended some time ago (you can blame me) to handle
other binary operators. Quoth le documentation:
Returns the right-hand side (that is, the second argument) of the
expression <expr>, when the operator of <expr> is one of the
relational operators `< <= = # equal notequal >= >', one of the
assignment operators `:= ::= : ::', or a user-defined binary infix
operator, as declared by `infix'.
When <expr> is an atom or its operator is something other than the
ones listed above, `rhs' returns 0.
best
Robert Dodier