#-
# CMP 407/770 final exam: add (homogeneous) sets to the Lehman programming language
#     due: noon on Friday, 12/21/12
#
# The program below illustrates the operations your compiler should support:
#     set literals,
#     the union of two sets (^+),
#     the intersection of two sets (^&),
#     the difference of two sets (^-),
#     membership in a set (^?),
#     non membership in a set (^!),
#     the size of a set, and
#     looping over the elements of a set.
#
# The sets in this example program are sets of CHARACTER.
# Your compiler should also support SET NUMBER, SET SEQ CHARACTER, SET SET BOOLEAN, etc..
# Your compiler need not support SET ANY, SET INVALID, etc..
#
# When you are finished submit an email stating clearly and succinctly what you have
# accomplished and what you have not.  Include a jar file containing your compiler in
# a form that I can import as an Eclipse project.
#
-#
{'a', 'e', 'i', 'o', 'u', 'y', 'y'} ~> SET CHARACTER A  # SET literal, a set of six characters
write @A
write "\nThe size of A is "
write |@A|
write "\nEnter another set of characters B as a string constant: "
read SEQ CHARACTER: y
write y
write "\n"
{ CHARACTER } ~> SET CHARACTER B                        # SET literal, an empty set of characters
for c : y do
  @B ^+ {c} ~:> B           # the union of two sets
write @B
write "\nA union     B is "
write @A ^+ @B              # the union of two sets
write "\nA intersect B is "
write @A ^& @B              # the intersection of two sets
write "\nA minus     B is "
write @A ^- @B              # the (asymmetric) difference of two sets (the elements of A that are not in B)
write "\n"
for c : @A do               # loop over the elements of a set
  if 0 == |c|%%2 then
    if @B ^? c write c      # membership in a set
  else
    if @B ^! c write c      # non membership in a set
write "\n"