first example with virtual dom; virtual dom still buggy

vdom.nim

@@ -0,0 +1,82 @@
+# Virtual DOM implementation
+
+from dom import Event
+
+type
+  VNodeKind* {.pure.} = enum
+    text,
+    anchor,
+    tdiv,
+    table, tr, td, th, thead, tbody,
+    link, span, label, br, select, option,
+    fieldset, input
+
+const
+  toTag*: array[VNodeKind, cstring] = [
+    cstring"#text", "A", "DIV", "TABLE", "TR", "TD", "TH", "THEAD", "TBODY", "LINK",
+    "SPAN", "LABEL", "BR", "SELECT", "OPTION", "FIELDSET", "INPUT"
+  ]
+
+type
+  EventKind* {.pure.} = enum
+    onclick, onkeyup, onkeydown, onkeypressed, onblur, onchange, onscroll
+
+const
+  toEventName*: array[EventKind, cstring] = [
+    cstring"click", "keyup", "keydown", "keypressed", "blur", "change", "scroll"
+  ]
+
+type
+  EventHandler* = proc (ev: Event; target: VNode) {.closure.}
+  VNode* = ref object
+    kind*: VNodeKind
+    id*, class*, text*: cstring
+    kids: seq[VNode]
+    # even index: key, odd index: value; done this way for memory efficiency:
+    attrs: seq[cstring]
+    events*: seq[(EventKind, EventHandler)]
+
+proc value*(n: VNode): cstring = n.text
+proc `value=`*(n: VNode; v: cstring) = n.text = v
+
+proc setAttr*(n: VNode; key: cstring; val: cstring = "") =
+  if n.attrs.isNil:
+    n.attrs = @[key, val]
+  else:
+    for i in countup(0, n.attrs.len-2, 2):
+      if n.attrs[i] == key:
+        n.attrs[i+1] = val
+        return
+    n.attrs.add key
+    n.attrs.add val
+
+proc getAttr*(n: VNode; key: cstring): cstring =
+  for i in countup(0, n.attrs.len-2, 2):
+    if n.attrs[i] == key: return n.attrs[i+1]
+
+proc len*(x: VNode): int = x.kids.len
+proc `[]`*(x: VNode; idx: int): VNode = x.kids[idx]
+proc add*(parent, kid: VNode) = parent.kids.add kid
+proc newVNode*(kind: VNodeKind): VNode = VNode(kind: kind)
+
+proc tree*(kind: VNodeKind; kids: varargs[VNode]): VNode =
+  result = newVNode(kind)
+  for k in kids: result.add k
+
+proc tree*(kind: VNodeKind; attrs: openarray[(cstring, cstring)];
+           kids: varargs[VNode]): VNode =
+  result = tree(kind, kids)
+  for a in attrs: result.setAttr(a[0], a[1])
+
+proc text*(s: string): VNode = VNode(kind: VNodeKind.text, text: cstring(s))
+proc text*(s: cstring): VNode = VNode(kind: VNodeKind.text, text: s)
+
+iterator items*(n: VNode): VNode =
+  for i in 0..<n.kids.len: yield n.kids[i]
+
+iterator attrs*(n: VNode): (cstring, cstring) =
+  for i in countup(0, n.attrs.len-2, 2):
+    yield (n.attrs[i], n.attrs[i+1])
+
+proc addEventListener*(n: VNode; event: EventKind; handler: EventHandler) =
+  n.events.add((event, handler))