Overwrite Data

[Positive07]

Yeah that is exactly what deepCopy does, your simpler shallow copy does the following

Code: Select all

t = {
    a = {
        b = "hello"
    }
}
for k,v in pairs(t) do
    x[k] = t[k]
end
x.a.b = "bye"
print(t.a.b) --"bye"
print(t==x) --"false"
print(t.a == x.a) --"true"

while deep copy

Code: Select all

t = {
    a = {
        b = "hello"
    }
}
x = deepCopy(t)
x.a.b = "bye"
print(t.a.b) --"hello"
print(t == x) --"false"
print (t.a == x.a) --"false"

I think that Robins code breaks when you do this though:

Code: Select all

t = {
    a = t
}
x = deepCopy(t)

Since it can't handle table loops, if you wanted to do this you would first have to detect the loops with parsing... and that is really hard... maybe there is a library to do this

[khamarr3524]

Right well, it should suffice for my usage. The data files for Units are static and formatted by hand. Nothing strange should be going on in there. I will simply use a recursion method. I'll do something like

Code: Select all

function copyTable(t)
  local tbl = {}
  for k, v in pairs(t) do
    if type(v) == "table" then
     tbl[k] = copyTable(v)
    end
    tbl[k] = v
  end
  return tbl
end

I'm assuming this would work just fine?

[Positive07]

Yeah indeed, it is really similar to deep copy

[ivan]

Minor bug:

Code: Select all

    if type(v) == "table" then
     tbl[k] = copyTable(v)
    end
    tbl[k] = v -- overwrites the copied table reference

Should probably be

Code: Select all

    if type(v) == "table" then
     tbl[k] = copyTable(v)
    else
      tbl[k] = v
    end

[Robin]

I think that Robins code breaks when you do this though:

Code: Select all

t = {
    a = t
}
x = deepCopy(t)

Since it can't handle table loops,

Actually, that's exactly the sort of thing my code fixed, compared to some more naive attempts at deep copying.

(Also, that should really be something like t = {}; t.a = t, but yeah.)