Problem with global variables

[Philippe Lhoste <PhiLho@...>]

Ha, I though I was starting to understand how closures, upvalues and
variable scope was working on Lua, and I stumble upon a puzzling problem.

Reduced to a simple form, I have the following code:
--%<-----
globalVar = 100
aTable = { "a", "b", "c", "d" }

function List(i, val)
  print(globalVar, i, val)
end

for globalVar = 0, 2 do
  print("Entry #" .. globalVar)
  for i, v in aTable do
    List(i, v)
  end
end
----->%--
The result, both on Lua 4.0 and Lua 5.0 is:
Entry #0
100     1       a
100     2       b
100     3       c
100     4       d
Entry #1
100     1       a
100     2       b
100     3       c
100     4       d
Entry #2
100     1       a
100     2       b
100     3       c
100     4       d

Obiviously, when I declare the List function, it takes a snapshot of the
global values used inside it and uses them instead of the current value.

1) I though it was only true for local values;
2) Using upvalue %globalVar doesn't change anything on Lua 4.0 and generates
a warning on Lua 5.0;
3) I though this problem was lifted in Lua 5.0.

Of course, I can give globalVar as parameter to List, but my initial code
used foreach, where I cannot do that.

Oh, OK. I never really got around this for syntax...
>From the manual: "The variable var [loop counter] is local to the statement;
you cannot use its value after the for ends." And for what it is worth,
neither on a an external function! (?)

So the correct form of my program is:

for k = 0, 2 do
  print("Entry #" .. k)
  globalVar = k
  for i, v in aTable do
    List(i, v)
  end
end

Since I have found the solution of my own problem, this e-mail is already
obsolete, but I send it anyway, because it can help other newbies...

Is it normal the problem persists in Lua 5.0?

Regards.

-- 
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Philippe Lhoste (Paris -- France)
Professional programmer and amateur artist
http://jove.prohosting.com/~philho/
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