Lunatic: prohibit initial assigns creating new globals, add some must-fail tests

git-svn-id: https://svn.eduke32.com/eduke32@2294 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/source/lunatic/defs.ilua

@@ -165,6 +165,8 @@ DBG_.loadstring = oG.loadstring
 ---- Set up restricted access to ffi.C from lunatic. ----
 local ffiC = ffi.C
 
+-- TODO: error(...) --> error(..., 2) to blame the caller?
+
 local det = {}  -- dummy empty table
 local tmpmt = {
     __index = function() error('dummy variable: read access forbidden') end,
@@ -191,7 +193,7 @@ gv = {
 }
 local tmpmt = {
     __index = ffiC,
-    __newindex = function() error("cannot create new fields in 'gv'") end,
+    __newindex = function() error("cannot create new or write into existing fields of 'gv'") end,
     __metatable = true,
 }
 oG.setmetatable(gv, tmpmt)
@@ -204,7 +206,7 @@ local tmpmt = {
                   error('out-of-bounds sector[] read access')
               end,
 
-    __newindex = function(tab, key, val) error('cannot write to sector[] struct directly') end,
+    __newindex = function(tab, key, val) error('cannot write directly to sector[] struct') end,
     __metatable = true,
 }
 oG.setmetatable(sector, tmpmt)
@@ -216,7 +218,7 @@ local tmpmt = {
                   error('out-of-bounds wall[] read access')
               end,
 
-    __newindex = function(tab, key, val) error('cannot write to wall[] struct directly') end,
+    __newindex = function(tab, key, val) error('cannot write directly to wall[] struct') end,
     __metatable = true,
 }
 oG.setmetatable(wall, tmpmt)
@@ -232,7 +234,7 @@ local function creategtab(ctab, maxidx, name)
                       error('out-of-bounds '..name..' read access')
                   end,
         __newindex = function(tab, key, val)
-                         error('cannot write to '..name)
+                         error('cannot write directly to '..name)
                      end,
         __metatable = true,
     }
@@ -304,5 +306,21 @@ G_.actor = actor
 G_.spritesofsect = spritesofsect
 G_.spritesofstat = spritesofstat
 
+-- 'simple' code for prohibiting initial assignments to create new variables,
+-- from 14.2 of PiL
+function gamevar(name, initval)  -- aka 'declare'
+    rawset(G_, name, initval or false)
+end
+
+setmetatable(
+    G_, {
+        __newindex = function (_, n)
+            error("attempt to write to undeclared variable "..n, 2)
+        end,
+        __index = function (_, n)
+            error("attempt to read undeclared variable "..n, 2)
+        end,
+        })
+
 -- change the environment of the running Lua thread to the table G_
 setfenv(0, G_)

polymer/eduke32/source/lunatic/test.elua

@@ -14,6 +14,8 @@ end
 local i
 
 print('tweaking sector pals')
+print('numsectors: ' .. gv.numsectors)
+
 ---[[
 for i = 0, gv.numsectors/2 do
     sector[i].floorpal = 1;
@@ -35,6 +37,9 @@ for spr in spritesofsect(236) do
     print('#spr', spr)
 end
 
+--this is a problem
+--actor = {}
+
 actor[562].flags = bit.bor(actor[562].flags, 2);   -- pal 6 with goggles on front SEENINE
 
 --]]
@@ -48,8 +53,13 @@ checkfail('setmetatable(sprite, {})')  -- set metatable forbidden
 checkfail('sector[-1].ceilingpal = 4')  -- oob write access
 checkfail('sector[0].wallnum = 0')  -- wallnum member is read-only
 checkfail('gv.numsectors = 4')  -- gv.numsectors is read-only
+checkfail('gv.QWE = 4')  -- cannot create new fields in 'gv'
 checkfail('sector[4] = sector[6]')  -- direct sector write access forbidden
+checkfail('nextspritesect[4] = -666')  -- that would be horrible...
+checkfail('print(nextspritesect[4].whatfield)')  -- we're indexing a plain array!
+checkfail('wall[4].QWE = 123')  -- creating new keys forbidden... handled by LuaJit
 checkfail("require('os')")  -- 'require' has been thrown away to be replaced by
                             -- something more restricted later
+checkfail("new_global = 345")  -- we should declare globals
 
 print('--- end test script ---')