Merge branch 'draft/refs' of https://github.com/bluenote10/karax into bluenote10-draft/refs

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>

experiments/refs/demo.nim

@@ -0,0 +1,56 @@
+include karaxprelude
+import future, sequtils
+
+type
+  CustomRef = ref object of VNodeRef
+
+method onAttach(r: CustomRef) =
+  kout(cstring"custom ref attached")
+
+method onDetach(r: CustomRef) =
+  kout(cstring"custom ref detached")
+
+var
+  modelData = @[5, 2, 4]
+
+  refA = VNodeRef()
+  refB = VNodeRef()
+  refC = CustomRef()
+  refSeq = newSeq[VNodeRef]()
+
+proc onClick(ev: Event, n: VNode) =
+  modelData.add(0)
+
+proc showRefs() =
+  kout(refA)
+  kout(refB)
+  kout(refC)
+  kout(refSeq.map(nref => nref.vnode))
+
+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
+      if modelData.len mod 2 == 0:
+        tdiv(nref=refA):
+          text "A"
+        tdiv(nref=refB):
+          text "B"
+        tdiv(nref=refC):
+          text "C"
+      # 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, showRefs)

experiments/refs/demo.nims

@@ -0,0 +1 @@
+--path: "../../src"

src/karax.nim

@@ -79,8 +79,16 @@ 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.nref.onDetach()
+  n.dom = nil
+template attach(n: VNode) =
+  if not n.nref.isNil():
+    n.nref.vnode = n
+    n.nref.onAttach()
+  n.dom = result
 
 proc vnodeToDom(n: VNode; kxi: KaraxInstance): Node =
   if n.kind == VNodeKind.text:

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

src/vdom.nim

@@ -101,6 +101,9 @@ macro buildLookupTables(): untyped =
 buildLookupTables()
 
 type
+  VNodeRef* = ref object of RootObj
+    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]
@@ -118,6 +122,10 @@ type
     dom*: Node ## the attached real DOM node. Can be 'nil' if the virtual node
                ## is not part of the virtual DOM anymore.
 
+method onAttach*(v: VNodeRef) {.base.} = discard
+method onDetach*(v: VNodeRef) {.base.} = discard
+method changed*(v: VNodeRef): bool {.base.} = false
+
 proc value*(n: VNode): cstring = n.text
 proc `value=`*(n: VNode; v: cstring) = n.text = v