improved handling of nested transactions

add nested transaction support to protocol
allow deferring validation to parent transaction
process each update request within a nested transaction

1 files changed, 6 insertions, 2 deletions

diff --git a/acf/util.lua b/acf/util.lua
index 9788c81..9ca287c 100644
--- a/acf/util.lua
+++ b/acf/util.lua
@@ -10,11 +10,15 @@ function setdefault(t, k, v)
    return t[k]
 end
 
-function setdefaults(dst, src)
-   for k, v in pairs(src) do if dst[k] == nil then dst[k] = v end end
+function update(dst, src, preserve)
+   for k, v in pairs(src) do
+      if not preserve or dst[k] == nil then dst[k] = v end
+   end
    return dst
 end
 
+function setdefaults(dst, src) return update(dst, src, true) end
+
 function copy(var)
    return type(var) == 'table' and setdefaults({}, var) or var
 end