Have s:={'a', 'b'};
a:=4;
naturally s[1] resolves to 4. Moreover, eval(s[1],1)=4, so s successfully should forget about a.
But...
a:='a'; and s[1] returms... again a.
So, why dereferencing of pointers is not the same as 'eval 1-level' resolving?
How actually can i unassign 'a' having s only?
Or (not obviously, but same!) related question:
how to obtain s1:={'a', 'b'} having s={a,b} with nonresolvable a and b .i.e. eval(smth, -1)?