From 2d58b8f49ec03fe3d4ad843085ffe09880e3f888 Mon Sep 17 00:00:00 2001
From: Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
Date: Wed, 11 Mar 2015 11:31:36 +0200
Subject: model: callable topology table for relative traversal

---
 aconf/model/root.lua | 48 ++++++++++++++++++++++++------------------------
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/aconf/model/root.lua b/aconf/model/root.lua
index e8525db..2a135f2 100644
--- a/aconf/model/root.lua
+++ b/aconf/model/root.lua
@@ -34,32 +34,32 @@ function M.RootModel:meta(path)
 end
 
 
-local _topology = {}
 local order = 0
-
-function M.topology(addr, create)
-   local top = _topology
-   if type(addr) == 'table' then addr = util.copy(addr)
-   else addr = address.split(addr) end
-
-   local function defaults(top)
-      return util.setdefaults(top, {members={}, paths={}, referrers={}})
-   end
-
-   while #addr > 0 do
-      local comp = address.escape(addr[1])
-      if create then
-	 top = setdefault(defaults(top).members, comp, {order=order})
-	 order = order + 1
-      else
-	 top = top.members[comp] or top.members['*']
-	 if not top then return end
+M.topology = setmetatable(
+   {},
+   {
+      __call=function(self, addr, create)
+	 util.setdefaults(self, {members={}, paths={}, referrers={}})
+
+	 if type(addr) == 'table' then addr = util.copy(addr)
+	 else addr = address.split(addr) end
+	 if not addr[1] then return self end
+
+	 local comp = address.escape(addr[1])
+	 local top
+	 if create then
+	    top = setdefault(self.members, comp, {order=order})
+	    order = order + 1
+	 else
+	    top = self.members[comp] or self.members['*']
+	    if not top then return end
+	 end
+	 table.remove(addr, 1)
+
+	 return setmetatable(top, getmetatable(self))(addr, create)
       end
-      table.remove(addr, 1)
-   end
-
-   return defaults(top)
-end
+   }
+)
 
 function M.register(name, field, params)
    if not params then params = {} end
-- 
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