Use R ::= QQ[x,y,z];
P := Record[ I = Ideal(x,y^2z), F = x^2 + y, Misc = [1,3,4]];
P.I;
Ideal(x, y^2  z)

P.F;
x^2 + y

P.Misc;
[1, 3, 4]

P.Misc[2];
3

P.Date := "1/1/98";
P;
Record[Date = "1/1/98", F = x^2 + y, I = Ideal(x, y^2  z), Misc = [1, 3, 4]]

P["I"];  equivalent to P.I
Ideal(x, y^2  z)

P["Misc",3];  equivalent to P.Misc[3]
4

