root/src/lua/etc/strict.lua

Revision 22d1941d0ca5ba7027cdfa51ce34bd1d8fb1931e, 0.9 kB (checked in by Theo Schlossnagle <jesus@omniti.com>, 10 years ago)

take the version out... it is what it is

  • Property mode set to 100644
Line 
1 --
2 -- strict.lua
3 -- checks uses of undeclared global variables
4 -- All global variables must be 'declared' through a regular assignment
5 -- (even assigning nil will do) in a main chunk before being used
6 -- anywhere or assigned to inside a function.
7 --
8
9 local getinfo, error, rawset, rawget = debug.getinfo, error, rawset, rawget
10
11 local mt = getmetatable(_G)
12 if mt == nil then
13   mt = {}
14   setmetatable(_G, mt)
15 end
16
17 mt.__declared = {}
18
19 local function what ()
20   local d = getinfo(3, "S")
21   return d and d.what or "C"
22 end
23
24 mt.__newindex = function (t, n, v)
25   if not mt.__declared[n] then
26     local w = what()
27     if w ~= "main" and w ~= "C" then
28       error("assign to undeclared variable '"..n.."'", 2)
29     end
30     mt.__declared[n] = true
31   end
32   rawset(t, n, v)
33 end
34  
35 mt.__index = function (t, n)
36   if not mt.__declared[n] and what() ~= "C" then
37     error("variable '"..n.."' is not declared", 2)
38   end
39   return rawget(t, n)
40 end
41
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