1 files changed, 12 insertions, 0 deletions

diff --git a/libs/lua/test/readonly.lua b/libs/lua/test/readonly.lua
new file mode 100644
index 0000000..85c0b4e
--- /dev/null
+++ b/libs/lua/test/readonly.lua
@@ -0,0 +1,12 @@
+-- make global variables readonly
+
+local f=function (t,i) error("cannot redefine global variable `"..i.."'",2) end
+local g={}
+local G=getfenv()
+setmetatable(g,{__index=G,__newindex=f})
+setfenv(1,g)
+
+-- an example
+rawset(g,"x",3)
+x=2
+y=1     -- cannot redefine `y'