Learning Guide Learning Guide

5.4 Evaluation Rules • 199> ’1-1’;0> ’p+q-i-p+3*q’;4 q − iIf you enclose a simple variable in right single quotes, the result is thename of the variable. You can use this method to unassign a variable.> x := 1;x := 1> x;1> x := ’x’;x := x> x;xHowever, in general, you must use evaln.> i := 4;i := 4> a[i] := 9;a 4 := 9Note that ’a[i]’ is a[i] not a[4].> ’a[i]’;