diff options
author | Lua Team <team@lua.org> | 2005-09-09 12:00:00 +0000 |
---|---|---|
committer | repogen <> | 2005-09-09 12:00:00 +0000 |
commit | bd80c4ee9b6d9464cf9f3ff4ee41890d8b3ca9e6 (patch) | |
tree | e1d7c1b341ccb9a3a1fb044ac6e67b5a5e0259b7 /etc/strict.lua | |
parent | bf6b5550cdfbc0c4a3a4577776ad76628d80718e (diff) | |
download | lua-github-5.1-alpha.tar.gz |
Lua 5.1-alpha5.1-alpha
Diffstat (limited to 'etc/strict.lua')
-rw-r--r-- | etc/strict.lua | 34 |
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 + |