Homework #6 Solution Sketches

1)

fun makeset(nil) = nil
|   makeset(x::xs) = if member(x,xs) then makeset(xs)
		     else x::makeset(xs);

2)

datatype boolexp = Value of bool |  Prop of string
|  AND of boolexp * boolexp |  OR of boolexp * boolexp |  NOT of boolexp;

fun eval (Value (x), L) = x
|   eval (Prop (x), L) = member (x,L)
|   eval (AND (x, y), L) = eval (x, L) andalso eval (y, L)
|   eval (OR (x, y), L) = eval (x, L) orelse eval (y, L)
|   eval (NOT (x), L) = not (eval (x, L));