An algebraic extension to LISP

An algebraic facility for LISP is quite desirable. Such a capability is motivated by the desire to utilize the primitive LISP arithmetic functions at the algebraic expression level. The requirement for a means of evaluating expressions might very well arise from applications in algebraic manipulation. Thus, the user, having performed some sort of transformation on an algebraic expression, might wish to have the resulting expression evaluated for a specific set of values. This facility, in response to this requirement, has the acronym "LEAF" (LISP Extended Algebraic Facility).