Allow limited access to unsafepairs/unsafenext

luprex/core/cpp/table.cpp

@@ -313,7 +313,7 @@ static void auxsort (lua_State *L, int tab, int l, int u) {
     }                          /* repeat the routine for the larger one */
 }
 
-int table_sortedpairs(lua_State *L, bool *unsortable) {
+int table_getpairs(lua_State *L, bool sort, bool *unsortable) {
     lua_checkstack(L, 40);
     LuaArg tab;
     LuaVar key, value;
@@ -328,7 +328,10 @@ int table_sortedpairs(lua_State *L, bool *unsortable) {
     lua_pushnil(L);
     int total = 0;
     while (lua_next(L, tab.index()) != 0) {
-        total += 1;
+        int ktype = lua_type(L, -2);
+        if (ktype == LUA_TNUMBER || ktype == LUA_TSTRING || ktype == LUA_TBOOLEAN) {
+            total += 1;
+        }
         lua_pop(L, 1);
     }
     // Create the table, store the initial 1.
@@ -350,7 +353,9 @@ int table_sortedpairs(lua_State *L, bool *unsortable) {
             lua_pop(L, 1);
         }
     }
-    auxsort(L, pairs.index(), 1, total);
+    if (sort) {
+        auxsort(L, pairs.index(), 1, total);
+    }
     return LS.result();
 }
 
@@ -362,7 +367,7 @@ int table_sortedpairs(lua_State *L, bool *unsortable) {
 //
 /////////////////////////////////////////////////////////////
 
-static int nextsortedpair(lua_State *L) {
+LuaDefine(table_nextpair, "c") {
     if (lua_gettop(L) < 2) {
         luaL_error(L, "Not enough arguments to nextpair");
     }
@@ -387,18 +392,37 @@ static int nextsortedpair(lua_State *L) {
 //
 /////////////////////////////////////////////////////////////
 
+LuaDefine(table_unsafenext, "c") {
+  luaL_checktype(L, 1, LUA_TTABLE);
+  lua_settop(L, 2);  /* create a 2nd argument if there isn't one */
+  if (lua_next(L, 1))
+    return 2;
+  else {
+    lua_pushnil(L);
+    return 1;
+  }
+}
+
+LuaDefine(table_unsafepairs, "c") {
+    luaL_checktype(L, 1, LUA_TTABLE);  /* argument must be a table */
+    lua_pushcfunction(L, table_unsafenext);  /* will return generator, */
+    lua_pushvalue(L, 1);  /* state, */
+    lua_pushnil(L);
+    return 3;
+}
+
 LuaDefine(table_pairs, "f") {
     LuaArg tab;
     LuaRet closure, rtab, key;
     LuaStack LS(L, tab, closure, rtab, key);
     lua_pushvalue(L, tab.index());
     bool unsortable;
-    table_sortedpairs(L, &unsortable);
+    table_getpairs(L, true, &unsortable);
     if (unsortable) {
         luaL_error(L, "Cannot iterate over a table with unsortable keys");
     }
     lua_replace(L, rtab.index());
-    LS.set(closure, nextsortedpair);
+    LS.set(closure, table_nextpair);
     LS.set(key, LuaNil);
     return LS.result();
 }

luprex/core/cpp/table.hpp

@@ -78,10 +78,13 @@ int table_count(lua_State *L);
 // This is not exposed directly to lua, but it is used
 // in the new version of the 'pairs' iterator.
 //
-// The boolean 'unsortable' is set to indicate whether
-// or not the table contains unsortable values.
+// The boolean 'sort' is used to control whether the pairs
+// are to be sorted or not.
 //
-int table_sortedpairs(lua_State *L, bool *unsortable);
+// The boolean 'unsortable' returns a flag indicating
+// whether or not unsortable items were omitted.
+//
+int table_getpairs(lua_State *L, bool sort, bool *unsortable);
 
 // table_clear
 //