summaryrefslogtreecommitdiff
path: root/etc/strict.lua
diff options
context:
space:
mode:
authorLua Team <team@lua.org>2005-09-09 12:00:00 +0000
committerrepogen <>2005-09-09 12:00:00 +0000
commitbd80c4ee9b6d9464cf9f3ff4ee41890d8b3ca9e6 (patch)
treee1d7c1b341ccb9a3a1fb044ac6e67b5a5e0259b7 /etc/strict.lua
parentbf6b5550cdfbc0c4a3a4577776ad76628d80718e (diff)
downloadlua-github-5.1-alpha.tar.gz
Lua 5.1-alpha5.1-alpha
Diffstat (limited to 'etc/strict.lua')
-rw-r--r--etc/strict.lua34
1 files changed, 34 insertions, 0 deletions
diff --git a/etc/strict.lua b/etc/strict.lua
new file mode 100644
index 00000000..7c9fa159
--- /dev/null
+++ b/etc/strict.lua
@@ -0,0 +1,34 @@
+--
+-- strict.lua
+-- checks uses of undeclared global variables
+-- All global variables must be 'declared' through a regular assignment
+-- (even assigning nil will do) in a main chunk before being used
+-- anywhere or assigned to inside a function.
+--
+
+local mt = getmetatable(_G)
+if mt == nil then
+ mt = {}
+ setmetatable(_G, mt)
+end
+
+mt.__declared = {}
+
+mt.__newindex = function (t, n, v)
+ if not mt.__declared[n] then
+ local w = debug.getinfo(2, "S").what
+ if w ~= "main" and w ~= "C" then
+ error("assign to undeclared variable '"..n.."'", 2)
+ end
+ mt.__declared[n] = true
+ end
+ rawset(t, n, v)
+end
+
+mt.__index = function (t, n)
+ if not mt.__declared[n] and debug.getinfo(2, "S").what ~= "C" then
+ error("variable '"..n.."' is not declared", 2)
+ end
+ return rawget(t, n)
+end
+