#!F-adobe-helvetica-medium-r-normal--18*
#!N 
#!CDarkGreen 
#!N  #!Rvalsv Variables as Left-Side Values #!N #!EC #!N #!N All 
assignments in a macro's environment affect variables that are local to 
the macro. These variables, if they do not already exist, are 
created in the macro's environment when they are first used on 
the left-hand side of an assignment expression. Thus, a variable outside 
of a macro cannot be modified with that macro. #!N #!N 
The only way to make such a change is to propagate 
a new value out of the macro using its output formal 
parameters, and to use this returned value in an assignment statement 
in the enclosing environment. #!N #!N Given these semantics, it is 
possible for a local version of a variable to come into 
existence and obscure a more global version of a variable, midway 
through a macro's execution. #!N #!N #!N #!N #!N  #!F-adobe-times-medium-i-normal--18*   Next 
Topic #!EF #!N #!N  #!Lvarsv,dxall558 h Variables as Right-Side Values  #!EL  #!N  #!F-adobe-times-medium-i-normal--18*   #!N 
