Re: avoiding recursion in a dump_table function
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- Subject: Re: avoiding recursion in a dump_table function
- From: Sean Conner <sean@...>
- Date: 2011年5月10日 11:45:22 -0400
It was thus said that the Great Dave Collins once stated:
> I've got a large object which, for convenience of pulling data from it, is self-referencing. (sometimes I need items from a dept, sometimes I need all items).
>
> Essentially, I've got this:
>
> Flyer
> Departments
> Dept1
> Item1
> Item2
> Dept2
> Item3
> Item4
> Items
> Item1
> Item2
> Item3
> Item4
>
>
> When I need to look inside this table using the following dump_table method, I get infinite recursion.
>
> Any ideas on how I can add some smarts to my dump_table to defeat the infinite recursion?
>
> function dump_table(t, prefix)
> if(prefix == nil) then
> prefix = ""
> end
>
> local k,v
> for k,v in pairs(t) do
> if(type(v) == "table") then
> dump_table(v, prefix .. k .. ":")
> else
> print(prefix .. k .. "=" .. tostring(v))
> end
> end
> end
Try the following:
do
local did_it_already
function dump_table(t,prefix,initialized)
if not initialized then
did_it_already = {}
end
local prefix = prefix or ""
for k,v in pairs(t) do
if type(v) == 'table' and not did_it_already[v] then
did_it_already[v] = true
dump_table(v,prefix .. k .. ":",true)
else
print(prefix .. k .. "=" .. tostring(v))
end
end
end
end
The reason you were seeing infinite recursion was because of nested
tables. This routine keeps track of any tables already processed and skips
them.
-spc