add concat operation

ranges/typedranges.nim

@@ -145,3 +145,19 @@ proc `[]=`*[T, U, V](r: MutRange[T], s: HSlice[U, V], v: Range[T]) {.inline.} =
   r[s] = toOpenArray(v)
 
 proc baseAddr*[T](r: Range[T]): ptr T {.inline.} = r.start
+
+template toRange*[T](a: Range[T]): Range[T] = a
+
+proc concat*[T](v: varargs[Range[T], toRange]): seq[T] =
+  var len = 0
+  for c in v: inc(len, c.len)
+  result = newSeq[T](len)
+  len = 0
+  for c in v:
+    copyMem(result[len].addr, c.start, sizeof(T) * c.len)
+    inc(len, c.len)
+
+proc `&`*[T](a, b: Range[T]): seq[T] =
+  result = newSeq[T](a.len + b.len)
+  copyMem(result[0].addr, a.start, sizeof(T) * a.len)
+  copyMem(result[a.len].addr, b.start, sizeof(T) * b.len)

tests/ttypedranges.nim

@@ -26,3 +26,20 @@ suite "Typed ranges":
     var z = toRange(@[1, 2, 3, 4])
     check y == z
     check x != z
+
+  test "concat operation":
+    var a = toRange(@[1,2,3])
+    var b = toRange(@[4,5,6])
+    var c = toRange(@[7,8,9])
+    var d = @[1,2,3,4,5,6,7,8,9]
+    var e = @[1,2,3,4,5,6]
+    var f = @[4,5,6,7,8,9]
+    var x = concat(a, b, c)
+    var y = a & b
+    check x == d
+    check y == e
+    var z = concat(b, @[7,8,9])
+    check z == f
+
+    
+