add hash function

ranges/typedranges.nim

@@ -1,4 +1,4 @@
-import ./ptr_arith, typetraits
+import ./ptr_arith, typetraits, hashes
 
 const rangesGCHoldEnabled = not defined(rangesDisableGCHold)
 const unsafeAPIEnabled = defined(rangesEnableUnsafeAPI)
@@ -50,6 +50,14 @@ proc toRange*[T](a: seq[T]): Range[T] {.inline.} = toImmutableRange(a)
 
 converter toImmutableRange*[T](a: MutRange[T]): Range[T] {.inline.} = Range[T](a)
 
+proc hash*(x: Range): Hash =
+  var h: Hash = 0
+  when rangesGCHoldEnabled:
+    h = h !& hash(x.gcHold)
+  h = h !& hash(x.start)
+  h = h !& hash(x.mLen)
+  result = !$h
+  
 proc len*(r: Range): int {.inline.} = int(r.mLen)
 
 proc high*(r: Range): int {.inline.} = r.len - 1

tests/ttypedranges.nim

@@ -1,5 +1,5 @@
 import
-  unittest,
+  unittest, sets,
   ../ranges/typedranges
 
 suite "Typed ranges":
@@ -71,3 +71,11 @@ suite "Typed ranges":
     # check(r[0] == 5) # XXX: Uncomment once nim bug #8044 is fixed
     r[1] = 10
     check(r2[1] == 10)
+
+  test "hash function":
+    var a = toRange(@[1,2,3])
+    var b = toRange(@[4,5,6])
+    var c = toRange(@[7,8,9])
+    var x = toSet([a, b, c, a, b])
+    check x.len == 3
+    check a in x