first draft

Inital working version in version control

ElementNode.lua

@@ -0,0 +1,119 @@
+local Set = require "Set"
+
+local ElementNode = {}
+ElementNode.mt = {__index = ElementNode}
+function ElementNode:new(nameortext, node, descend, openstart, openend)
+  local instance = {
+    name = nameortext,
+    level = 0,
+    parent = nil,
+    root = nil,
+    nodes = {},
+    _openstart = openstart, _openend = openend,
+    _closestart = openstart, _closeend = openend,
+    attributes = {},
+    id = nil,
+    classes = {},
+    deepernodes = Set:new(),
+    deeperelements = {}, deeperattributes = {}, deeperids = {}, deeperclasses = {}
+  }
+  if not node then
+    instance.name = "root"
+    instance.root = instance
+    instance._text = nameortext
+    local length = string.len(nameortext)
+    instance._openstart, instance._openend = 1, length
+    instance._closestart, instance._closeend = 1, length
+  elseif descend then
+    instance.root = node.root
+    instance.parent = node
+    instance.level = node.level + 1
+    table.insert(node.nodes, instance)
+  else
+    instance.root = node.root
+    instance.parent = node.parent
+    instance.level = node.level
+    table.insert(node.parent.nodes, instance)
+  end
+  return setmetatable(instance, ElementNode.mt)
+end
+
+function ElementNode:gettext()
+  return string.sub(self.root._text, self._openstart, self._closeend)
+end
+
+function ElementNode:getcontent()
+  return string.sub(self.root._text, self._openend + 1, self._closestart - 1)
+end
+
+function ElementNode:addattribute(k, v)
+  self.attributes[k] = v
+  if string.lower(k) == "id" then
+    self.id = v
+  end
+  -- class attribute contains "space-separated tokens", each of which we'd like quick access to
+  if string.lower(k) == "class" then
+    for class in string.gmatch(v, "%S+") do
+      table.insert(self.classes, class)
+    end
+  end
+end
+
+local function insert(list, name, node)
+  if not list[name] then
+    list[name] = Set:new()
+  end
+  list[name]:add(node)
+end
+
+function ElementNode:close(closestart, closeend)
+  if closestart and closeend then
+    self._closestart, self._closeend = closestart, closeend
+  end
+  -- inform hihger level nodes about this element's existence in their branches
+  local node = self
+  while true do
+    node = node.parent
+    if not node then break end
+    node.deepernodes:add(self)
+    insert(node.deeperelements, self.name, self)
+    for k in pairs(self.attributes) do
+      insert(node.deeperattributes, k, self)
+    end
+    if self.id then
+      insert(node.deeperids, self.id, self)
+    end
+    for _,v in ipairs(self.classes) do
+      insert(node.deeperclasses, v, self)
+    end
+  end
+end
+
+function ElementNode:select(s)
+  if not s or type(s) ~= "string" then return {} end
+  local subjects = Set:new({self})
+  local resultset
+  local childrenonly
+  for part in string.gmatch(s, "%S+") do
+    if part == ">" then childrenonly = true goto nextpart end
+    resultset = Set:new()
+    for subject in pairs(subjects) do
+      local init = subject.deepernodes
+      if childrenonly then init = Set:new(subject.nodes) childrenonly = false end
+      resultset = resultset + init
+    end
+    if part == "*" then goto nextpart end
+    for t, w in string.gmatch(part, "([%[#%.]?)([^%[%]#%.]+)") do
+      if t == "" then resultset = resultset * self.deeperelements[w]
+      elseif t == "[" then resultset = resultset * self.deeperattributes[w]
+      elseif t == "#" then resultset = resultset * self.deeperids[w]
+      elseif t == "." then resultset = resultset * self.deeperclasses[w]
+      end
+    end
+    subjects = Set:new(resultset)
+    ::nextpart::
+  end
+  return resultset:tolist()
+end
+
+return ElementNode