Stub out the new global.set and global.get operators

luprex/cpp/core/globaldb.cpp

@@ -1,72 +1,74 @@
 #include "luastack.hpp"
 #include "globaldb.hpp"
 
-LuaDefine(global_once, "name", "for a given string, returns true exactly once") {
+
+LuaDefine(global_set, "varname, value",
+    "|Store data in the global data table."
+    "|"
+    "|You can store global data using global.set, then you can"
+    "|retrieve it using global.get.  You can also retrieve data using"
+    "|gv.varname, which is just shorthand for global.get.  You may not"
+    "|store data using gv.varname=value, this yields the error 'Use "
+    "|global.set to store data in the global data table.'"
+    "|"
+    "|Values stored using global.set are difference transmitted to all"
+    "|connected clients immediately.  When a new client connects,"
+    "|he will receive all the global data."
+    "|"
+    "|The global data table is not the same thing as the lua "
+    "|environment table.  Trying to store data in the lua environment"
+    "|table will seem to work, at first, but the data will not get"
+    "|difference transmitted, and will eventually be cleared and lost."
+    "|Therefore, it is essential that global data be stored in the"
+    "|global data table (using global.set) instead of in the lua"
+    "|environment table."
+    "|"
+    "|There are certain restrictions on the values that you store."
+    "|The value can contain strings, numbers, simple tables, and"
+    "|tangibles.  Nothing else is allowed.  Simple tables are tables"
+    "|that don't have metatables, and that aren't special tables such"
+    "|as classes, the lua environment table, the registry, or the like."
+    "|"
+    "|When you store the value, a recursive copy is made and stored."
+    "|When you call global.get, you obtain the copy.  Any attempt to"
+    "|mutate the copy will fail with this lua error message: 'Tables"
+    "|returned by global.get are immutable.'  This rule prevents'"
+    "|aliasing between global data and other data structures."
+    "|") {
+    return 0;
+}
+
+LuaDefine(global_get, "varname", 
+    "|Get data stored using global.set"
+    "|"
+    "|See doc(global.set) for information on how to store global data."
+    "|") {
+    return 0;
+}
+
+LuaDefine(global_once, "name",
+    "|For a given string, returns true exactly once"
+    "|"
+    "|The semantics and difference transmission behavior of global.once"
+    "|are identical to the semantics of global.set, since global.once"
+    "|uses global.set under the covers."
+    "|") {
     LuaArg name;
     LuaRet flag;
     LuaVar oncedb, val;
     LuaStack LS(L, name, flag, oncedb, val);
-
-    LS.guard_nopredict("global.once");
-
-    // Get a pointer to the oncedb.
-    LS.rawget(oncedb, LuaRegistry, "oncedb");
-    if (!LS.istable(oncedb)) {
-        LS.set(flag, false);
-        return LS.result();
-    }
-
-    LS.checkstring(name, "name");
-    LS.rawget(val, oncedb, name);
-    if (!LS.isnil(val)) {
-        LS.set(flag, false);
-        return LS.result();
-    }
-    LS.rawset(oncedb, name, true);
-    LS.set(flag, true);
-    return LS.result();
+    return 0;
 }
 
-
-LuaDefine(global_clearonce, "name", "reset the specified once-flag") {
+LuaDefine(global_clearonce, "name",
+    "|Reset the specified once-flag"
+    "|"
+    "|The semantics and difference transmission behavior of global.clearonce"
+    "|are identical to the semantics of global.set, since global.once"
+    "|uses global.set under the covers."
+    "|") {
     LuaArg name;
     LuaVar oncedb;
     LuaStack LS(L, name, oncedb);
-
-    LS.guard_nopredict("global.clearonce");    
-
-    // Get a pointer to the oncedb.
-    LS.rawget(oncedb, LuaRegistry, "oncedb");
-    if (!LS.istable(oncedb)) {
-        return LS.result();
-    }
-    LS.checkstring(name, "name");
-    LS.rawset(oncedb, name, LuaNil);
-    return LS.result();
-}
-
-LuaDefine(global_table, "globalname", "get a table where global data can be stored") {
-    LuaArg globalname;
-    LuaRet globaltab;
-    LuaVar globaldb;
-    LuaStack LS(L, globalname, globaltab, globaldb);
-    LS.checkstring(globalname, "globalname");
-
-    // Get a pointer to the globaldb.
-    LS.rawget(globaldb, LuaRegistry, "globaldb");
-
-    // Get the globaltab from the globaldb, sanity check it.
-    LS.rawget(globaltab, globaldb, globalname);
-    if (LS.istable(globaltab)) {
-        return LS.result();
-    } else if (!LS.isnil(globaltab)) {
-        luaL_error(L, "%s is not a global", LS.ckstring(globalname).c_str());
-    }
-
-    // Create a new globaltab and store it in the globaldb.
-    LS.newtable(globaltab);
-    LS.rawset(globaldb, globalname, globaltab);
-    LS.rawset(globaltab, "__global", globalname);
-    LS.settabletype(globaltab, LUA_TT_GLOBALDB);
-    return LS.result();
+    return 0;
 }