From b2b9a8324f1c65d15fa5dac7d8d4e9dd734f8c65 Mon Sep 17 00:00:00 2001
From: kitsunyan
Date: Sat, 21 Apr 2018 10:09:43 +0300
Subject: Introduce "List[T]" type

---
 src/lists.nim | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 src/lists.nim

(limited to 'src/lists.nim')

diff --git a/src/lists.nim b/src/lists.nim
new file mode 100644
index 0000000..cf1b0c5
--- /dev/null
+++ b/src/lists.nim
@@ -0,0 +1,58 @@
+import sequtils
+
+type
+  List*[T] = ref object of RootObj
+    next: List[T]
+    data: T
+
+iterator items*[T](list: List[T]): T =
+  var l = list
+  while l != nil:
+    yield l.data
+    l = l.next
+
+proc list*[T](items: varargs[T]): List[T] =
+  var last: List[T] = nil
+  for i in countdown(items.high, items.low):
+    new(result)
+    result.data = items[i]
+    result.next = last
+    last = result
+
+proc reversed*[T](list: List[T]): List[T] =
+  var last: List[T] = nil
+  for item in list:
+    new(result)
+    result.data = item
+    result.next = last
+    last = result
+
+proc `^&`*[T](data: T, list: List[T]): List[T] =
+  new(result)
+  result.next = list
+  result.data = data
+
+proc `^&`*[T](data: openarray[T], list: List[T]): List[T] =
+  result = list
+  for i in countdown(data.high, data.low):
+    result = data[i] ^& result
+
+static:
+  # lists test
+  template testList[T](list: List[T], testSeq: openArray[T]) =
+    block:
+      let s = toSeq(list.items)
+      if s != @testSeq: raise newException(SystemError, "list: " & $s)
+
+  let l1 = list[int]()
+  testList(l1, [])
+  let l2 = 1 ^& l1
+  testList(l2, [1])
+  let l3 = list(1, 2, 3)
+  testList(l3, [1, 2, 3])
+  let l4 = l3.reversed
+  testList(l4, [3, 2, 1])
+  let l5 = 4 ^& l4
+  testList(l5, [4, 3, 2, 1])
+  let l6 = 8 ^& [7, 6] ^& 5 ^& l5
+  testList(l6, [8, 7, 6, 5, 4, 3, 2, 1])
-- 
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