By loading the file SHARE2;LRATS FASL one gains access to the two functions
described below:

LRATSUBST(list_of_equations,exp) is analogous to SUBST(list_of_equations,exp)
except that it uses RATSUBST instead of SUBST.  The first argument of LRATSUBST
must be an equation or a list of equations identical in format to the form
accepted by SUBST (see the MACSYMA manual, p. 81).  The substitutions are
made in the order given by the list of equations, that is, from left to right.

FULLRATSUBST(a,b,c) is the same as RATSUBST except that it calls itself
recursively on its result until that result stops changing.  This function
is useful when the replacement expression and the replaced expression have
one or more variables in common.  FULLRATSUBST will also accept its arguments
in the format of LRATSUBST.  That is,  the first argument may be a single
substitution equation or a list of such equations, while the second argument
is the expression being processed.

A demo is available in SHARE2;LRATS DEMO.
Author: ASB