# HG changeset patch
# User jbe
# Date 1452364176 -3600
# Node ID 04692707527036401bd6a7802b15456870aaf4b1
# Parent  0dff5e2f659cbf776414e5a65362bb93d34b3eca
Proxy table to directly access column-values of a database row (e.g. if document_column is set or for reserved method names)

diff -r 0dff5e2f659c -r 046927075270 libraries/mondelefant/mondelefant_native.autodoc.lua
--- a/libraries/mondelefant/mondelefant_native.autodoc.lua	Sat Jan 09 17:32:30 2016 +0100
+++ b/libraries/mondelefant/mondelefant_native.autodoc.lua	Sat Jan 09 19:29:36 2016 +0100
@@ -331,3 +331,15 @@
 -- static int mondelefant_class_get_reference(lua_State *L)
 --//--
 
+
+--[[--
+<db_object>.columns  -- proxy table mapping column names to their values
+
+This attribute can be used to access column values directly (helpful if <db_class>:document_column is set). Currently pairs(...) and ipairs(...) are not implemented on this proxy table.
+
+--]]--
+-- implemented in mondelefant_native.c as
+-- static const struct luaL_Reg mondelefant_columns_mt_functions[]
+--
+--//--
+
diff -r 0dff5e2f659c -r 046927075270 libraries/mondelefant/mondelefant_native.c
--- a/libraries/mondelefant/mondelefant_native.c	Sat Jan 09 17:32:30 2016 +0100
+++ b/libraries/mondelefant/mondelefant_native.c	Sat Jan 09 19:29:36 2016 +0100
@@ -23,6 +23,14 @@
 #define MONDELEFANT_CLASS_MT_REGKEY (MONDELEFANT_REGKEY "class")
 // registry key of default prototype for models/classes:
 #define MONDELEFANT_CLASS_PROTO_REGKEY (MONDELEFANT_REGKEY "class_proto")
+// registry key of meta-table for column proxy:
+#define MONDELEFANT_COLUMNS_MT_REGKEY (MONDELEFANT_REGKEY "columns")
+// table (lightuserdata) key to store result object in column proxy:
+// (address of struct used as unique reference)
+#define MONDELEFANT_COLUMNS_RESULT_LUKEY ((void *)&mondelefant_columns_result_lukey_dummy)
+
+// dummy variable for MONDELEFANT_COLUMNS_RESULT_LUKEY reference:
+char mondelefant_columns_result_lukey_dummy;
 
 // C-structure for database connection userdata:
 typedef struct {
@@ -573,7 +581,13 @@
   lua_setfield(L, 2, "_dirty");
   lua_newtable(L);  // 3
   lua_setfield(L, 2, "_ref");  // nil=no info, false=nil, else table
-  // return created database result object:
+  // create column proxy (field "columns" in result object):
+  lua_newtable(L);  // 3
+  luaL_setmetatable(L, MONDELEFANT_COLUMNS_MT_REGKEY);
+  lua_pushvalue(L, 2);  // 4
+  lua_rawsetp(L, 3, MONDELEFANT_COLUMNS_RESULT_LUKEY);
+  lua_setfield(L, 2, "columns");
+  // return created database result object (from stack position 2):
   return 1;
 }
 
@@ -1825,6 +1839,33 @@
   }
 }
 
+// meta-method "__index" of column proxy:
+static int mondelefant_columns_index(lua_State *L) {
+  luaL_checktype(L, 1, LUA_TTABLE);
+  lua_settop(L, 2);
+  lua_rawgetp(L, 1, MONDELEFANT_COLUMNS_RESULT_LUKEY);  // 3
+  lua_getfield(L, 3, "_data");  // 4
+  lua_pushvalue(L, 2);  // 5
+  lua_gettable(L, 4);  // 5
+  return 1;
+}
+
+// meta-method "__newindex" of column proxy:
+static int mondelefant_columns_newindex(lua_State *L) {
+  luaL_checktype(L, 1, LUA_TTABLE);
+  lua_settop(L, 3);
+  lua_rawgetp(L, 1, MONDELEFANT_COLUMNS_RESULT_LUKEY);  // 4
+  lua_getfield(L, 4, "_data");  // 5
+  lua_getfield(L, 4, "_dirty");  // 6
+  lua_pushvalue(L, 2);
+  lua_pushvalue(L, 3);
+  lua_settable(L, 5);
+  lua_pushvalue(L, 2);
+  lua_pushboolean(L, 1);
+  lua_settable(L, 6);
+  return 0;
+}
+
 // meta-method "__index" of classes (models):
 static int mondelefant_class_index(lua_State *L) {
   // perform lookup in prototype:
@@ -1888,7 +1929,7 @@
   {NULL, NULL}
 };
 
-// registration information for methods of database result lists/objects:
+// registration information for meta-methods of classes (models):
 static const struct luaL_Reg mondelefant_class_mt_functions[] = {
   {"__index", mondelefant_class_index},
   {NULL, NULL}
@@ -1913,9 +1954,21 @@
   {NULL, NULL}
 };
 
+// registration information for meta-methods of column proxy:
+static const struct luaL_Reg mondelefant_columns_mt_functions[] = {
+  {"__index", mondelefant_columns_index},
+  {"__newindex", mondelefant_columns_newindex},
+  {NULL, NULL}
+};
+
 // luaopen function to initialize/register library:
 int luaopen_mondelefant_native(lua_State *L) {
   lua_settop(L, 0);
+
+  lua_newtable(L);  // meta-table for columns proxy
+  luaL_setfuncs(L, mondelefant_columns_mt_functions, 0);
+  lua_setfield(L, LUA_REGISTRYINDEX, MONDELEFANT_COLUMNS_MT_REGKEY);
+
   lua_newtable(L);  // module at stack position 1
   luaL_setfuncs(L, mondelefant_module_functions, 0);