1 files changed, 54 insertions, 0 deletions
diff --git a/tests/iter/tgeniteratorinblock.nim b/tests/iter/tgeniteratorinblock.nim
new file mode 100644
index 000000000..2ab903996
--- /dev/null
+++ b/tests/iter/tgeniteratorinblock.nim
@@ -0,0 +1,54 @@
+discard """
+  output: '''30
+60
+90
+150
+180
+210
+240
+60
+180
+240
+[60, 180, 240]
+[60, 180]'''
+"""
+import std/enumerate
+
+template map[T; Y](i: iterable[T], fn: proc(x: T): Y): untyped =
+  iterator internal(): Y  {.gensym.} =
+    for it in i:
+      yield fn(it)
+  internal()
+
+template filter[T](i: iterable[T], fn: proc(x: T): bool): untyped =
+  iterator internal(): T {.gensym.} =
+    for it in i:
+      if fn(it):
+        yield it
+  internal()
+
+template group[T](i: iterable[T], amount: static int): untyped =
+  iterator internal(): array[amount, T] {.gensym.} =
+    var val: array[amount, T]
+    for ind, it in enumerate i:
+      val[ind mod amount] = it
+      if ind mod amount == amount - 1:
+        yield val
+  internal()
+
+var a = [10, 20, 30, 50, 60, 70, 80]
+
+proc mapFn(x: int): int = x * 3
+proc filterFn(x: int): bool = x mod 20 == 0
+
+for x in a.items.map(mapFn):
+  echo x
+
+for y in a.items.map(mapFn).filter(filterFn):
+  echo y
+
+for y in a.items.map(mapFn).filter(filterFn).group(3):
+  echo y
+
+for y in a.items.map(mapFn).filter(filterFn).group(2):
+  echo y