model: lazy evaluation for member metadata

1 files changed, 15 insertions, 9 deletions

diff --git a/acf2/model/node.lua b/acf2/model/node.lua
index f10cfce..45167af 100644
--- a/acf2/model/node.lua
+++ b/acf2/model/node.lua
@@ -61,13 +61,13 @@ function M.TreeNode:init(context)
 
    mt.__eq = equal_tns
    mt.dereference = true
-   mt.meta = {}
+   mt._meta = {}
    function mt.get(k, create) return mt.load(k, {create=create}) end
 
    if not mt.txn then return end
 
    if mt.parent then
-      mt.meta['ui-name'] = getmetatable(mt.parent).mmeta(
+      mt._meta['ui-name'] = getmetatable(mt.parent).mmeta(
 	 pth.name(mt.path)
       )['ui-name']
    end
@@ -170,15 +170,21 @@ function M.Collection:init(context, params)
 
    if not mt.txn then return end
 
-   mt.meta.type = 'collection'
-   mt.meta.members = field:meta()
-   mt.meta['ui-member'] = params.ui_member or mt.meta['ui-name']:gsub('s$', '')
-   mt.meta.widget = params.layout
+   mt._meta.type = 'collection'
+   mt._meta['ui-member'] = params.ui_member or mt._meta['ui-name']:gsub(
+      's$', ''
+   )
+   mt._meta.widget = params.layout
+
+   function mt.meta()
+      if not mt._meta.members then mt._meta.members = field:meta() end
+      return mt._meta
+   end
 
    function mt.mmeta(name)
-      local res = util.copy(mt.meta.members)
+      local res = util.copy(mt.meta().members)
       if name ~= pth.wildcard then
-	 res['ui-name'] = mt.meta['ui-member']..' '..name
+	 res['ui-name'] = mt._meta['ui-member']..' '..name
       end
       return res
    end
@@ -206,7 +212,7 @@ function M.List:init(context, params)
    super(self, M.List):init(context, params)
 
    local mt = getmetatable(self)
-   mt.meta.type = 'list'
+   mt._meta.type = 'list'
 
    local save = mt.save
    function mt.save(k, v)