Added logical set operations to TSet

tests/sets/tsets3.nim

@@ -0,0 +1,81 @@
+include sets
+
+let
+  s1: TSet[int] = toSet([1, 2, 4, 8, 16])
+  s2: TSet[int] = toSet([1, 2, 3, 5, 8])
+  s3: TSet[int] = toSet([3, 5, 7])
+
+block union:
+  let
+    s1_s2 = union(s1, s2)
+    s1_s3 = s1 or s3
+    s2_s3 = s2 or s3
+
+  assert s1_s2.len == 7
+  assert s1_s3.len == 8
+  assert s2_s3.len == 6
+
+  for i in s1:
+    assert i in s1_s2
+    assert i in s1_s3
+  for i in s2:
+    assert i in s1_s2
+    assert i in s2_s3
+  for i in s3:
+    assert i in s1_s3
+    assert i in s2_s3
+
+  assert((s1 or s1) == s1)
+  assert((s2 or s1) == s1_s2)
+
+block intersection:
+  let
+    s1_s2 = intersection(s1, s2)
+    s1_s3 = intersection(s1, s3)
+    s2_s3 = s2 and s3
+
+  assert s1_s2.len == 3
+  assert s1_s3.len == 0
+  assert s2_s3.len == 2
+
+  for i in s1_s2:
+    assert i in s1
+    assert i in s2
+  for i in s1_s3:
+    assert i in s1
+    assert i in s3
+  for i in s2_s3:
+    assert i in s2
+    assert i in s3
+
+  assert((s2 and s2) == s2)
+  assert((s3 and s2) == s2_s3)
+
+block symmetricDifference:
+  let
+    s1_s2 = symmetricDifference(s1, s2)
+    s1_s3 = s1 xor s3
+    s2_s3 = s2 xor s3
+
+  assert s1_s2.len == 4
+  assert s1_s3.len == 8
+  assert s2_s3.len == 4
+
+  for i in s1:
+    assert i in s1_s2 xor i in s2
+    assert i in s1_s3 xor i in s3
+  for i in s2:
+    assert i in s1_s2 xor i in s1
+    assert i in s2_s3 xor i in s3
+  for i in s3:
+    assert i in s1_s3 xor i in s1
+    assert i in s2_s3 xor i in s2
+
+  assert((s3 xor s3) == initSet[int]())
+  assert((s3 xor s1) == s1_s3)
+
+block disjoint:
+  assert(not disjoint(s1, s2))
+  assert disjoint(s1, s3)
+  assert(not disjoint(s2, s3))
+  assert(not disjoint(s2, s2))