Sorry in advance if this is an incorrect question. I'm fairly new to Lua and I'm not sure how to go about this. I want to access a variable stored in a table from a function variable. As far as I know there is no self-referencing tables before constructed.
An example would be this:
local bigTable = {
a = {
foo = 0,
bar = function(y)
print(foo) --Incorrect
end
}
}
What would be the best approach for this situation?
What you want to do is to create a table first, and append the keys to it:
local a = {}
a.foo = 0
a.bar = function()
print(a.foo)
end
local bigTable = {
a = a
}
bigTable.a.bar() -- prints 0
local bigTable = {
a = {
foo = 0,
bar = function(self, ...)
print(self.foo)
end,
}
}
-- Somewhere else in the code...
bigTable.a.bar(bigTable.a) --> 0
-- or the shorter but (almost) equivalent form:
bigTable.a:bar() --> prints 0
I anticipate your next question will be "What does the : do?", and for that there's lots of answers on SO already :)
Note that there's potential for a performance improvement here: if the above code gets called a lot, the bar method will be created again and again, so it could make sense to cache it; but that's pointless unless the surrounding code is already fast enough that this one allocation would have a noticeable impact on its runtime.
bar = function bigTable.a:bar(...) raises syntax error
bar = bar(self, ...) also gives syntax error
function bigTable.a.bar(y) print(bigTable.a.foo) endin the next statement after thebigTabledefinition.