From 14660f9d685d1b14cdead9cb09421f0f8ff7512e Mon Sep 17 00:00:00 2001
From: Fabian Keller <github.100.fkeller@spamgourmet.com>
Date: Thu, 15 Jun 2017 13:53:53 +0200
Subject: [PATCH] implemented refs draft

---
 experiments/refs/demo.html | 13 +++++++++++++
 experiments/refs/demo.nim  | 39 ++++++++++++++++++++++++++++++++++++++
 experiments/refs/demo.nims |  1 +
 src/karax.nim              | 10 ++++++++--
 src/karaxdsl.nim           |  2 +-
 src/vdom.nim               |  4 ++++
 6 files changed, 66 insertions(+), 3 deletions(-)
 create mode 100644 experiments/refs/demo.html
 create mode 100644 experiments/refs/demo.nim
 create mode 100644 experiments/refs/demo.nims

diff --git a/experiments/refs/demo.html b/experiments/refs/demo.html
new file mode 100644
index 0000000..e1fe419
--- /dev/null
+++ b/experiments/refs/demo.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+
+<html>
+<head>
+  <meta charSet="utf-8"/>
+  <title>Refs</title>
+</head>
+
+<body id="body">
+  <div id="ROOT"></div>
+  <script type="text/javascript" src="nimcache/demo.js"></script>
+</body>
+</html>
diff --git a/experiments/refs/demo.nim b/experiments/refs/demo.nim
new file mode 100644
index 0000000..dffb1e9
--- /dev/null
+++ b/experiments/refs/demo.nim
@@ -0,0 +1,39 @@
+include karaxprelude
+import random
+
+var
+  modelData = @[5, 2, 4]
+
+  refA = VNodeRef()
+  refB = VNodeRef()
+  refSeq = newSeq[VNodeRef]()
+
+proc onClick(ev: Event, n: VNode) =
+  kout(refA)
+  kout(refB)
+  kout(refSeq)
+
+proc secureRefSlot(i: int): VNodeRef =
+  while refSeq.len <= i:
+    refSeq.add(VNodeRef())
+  result = refSeq[i]
+
+proc view(): VNode =
+  result = buildHtml():
+    tdiv:
+      button(onclick=onClick):
+        text "click me"
+      # storing refs to single elements is straightforward now
+      tdiv(nref=refA):
+        text "A"
+      tdiv(nref=refB):
+        text "B"
+      # It's a bit more tricky when containers are involved:
+      for i, x in modelData.pairs:
+        tdiv(nref=secureRefSlot(i)):
+          text "List item: " & $x
+
+proc renderer(): VNode =
+  view()
+
+setRenderer renderer
diff --git a/experiments/refs/demo.nims b/experiments/refs/demo.nims
new file mode 100644
index 0000000..9028ff1
--- /dev/null
+++ b/experiments/refs/demo.nims
@@ -0,0 +1 @@
+--path: "../../src"
diff --git a/src/karax.nim b/src/karax.nim
index cc52e2f..d8a4cb1 100644
--- a/src/karax.nim
+++ b/src/karax.nim
@@ -65,8 +65,14 @@ proc wrapEvent(d: Node; n: VNode; k: EventKind; action: EventHandler) =
 
 # --------------------- DOM diff -----------------------------------------
 
-template detach(n: VNode) = n.dom = nil
-template attach(n: Vnode) = n.dom = result
+template detach(n: VNode) =
+  if not n.nref.isNil():
+    n.nref.vnode = nil
+  n.dom = nil
+template attach(n: VNode) =
+  if not n.nref.isNil():
+    n.nref.vnode = n
+  n.dom = result
 
 proc vnodeToDom(n: VNode): Node =
   if n.kind == VNodeKind.text:
diff --git a/src/karaxdsl.nim b/src/karaxdsl.nim
index 190545c..8693f5b 100644
--- a/src/karaxdsl.nim
+++ b/src/karaxdsl.nim
@@ -4,7 +4,7 @@ from strutils import startsWith, toLowerAscii
 
 const
   StmtContext = ["kout", "inc", "echo", "dec", "!"]
-  SpecialAttrs = ["id", "class", "value", "key", "style"]
+  SpecialAttrs = ["id", "class", "value", "key", "style", "nref"]
 
 proc getName(n: NimNode): string =
   case n.kind
diff --git a/src/vdom.nim b/src/vdom.nim
index d55e7b4..f4ccff8 100644
--- a/src/vdom.nim
+++ b/src/vdom.nim
@@ -101,6 +101,9 @@ macro buildLookupTables(): untyped =
 buildLookupTables()
 
 type
+  VNodeRef* = ref object
+    vnode*: VNode
+
   EventHandler* = proc (ev: Event; target: VNode) {.closure.}
   VKey* = int
 
@@ -108,6 +111,7 @@ type
     kind*: VNodeKind
     key*: VKey
     id*, class*, text*: cstring
+    nref*: VNodeRef
     kids: seq[VNode]
     # even index: key, odd index: value; done this way for memory efficiency:
     attrs: seq[cstring]