Concatenating keys and values of a table, without making a garbage heap

[Fodaro]

In the last couple of releases of Consolid8, I've been using a StaticPopup to report things to the user. I anchor a FontString to the left for the faction names, and one to the right for the values. To put the text into them, I wrote this piece of code:

local namesStr, valuesStr = "", ""
for key, value in pairs(data) do
    namesStr  = namesStr  .. key   .. "\n"
    valuesStr = valuesStr .. value .. "\n"
end

Thing is, it makes a lot of garbage. It'd be good to use table.concat, but that only uses the array part of a table. Although it's not called that often, I don't like the idea of the garbage that would be made if there was a lot of data. Any ideas?

[Slakah]

local function concatk(t, k, ...)
    local newk, newv = next(t, k)
    
    if not newv then return ... end
    
    return concatk(t, newk, newk, ...)
end
 
local function concatv(t, k, ...)
    local newk, newv = next(t, k)
    
    if not newv then return ... end
    
    return concatv(t, newk, newv, ...)
end
 
 
strjoin("\n", concatk(data, nil))
strjoin("\n", concatv(data, nil))

[Fodaro]

Thanks for that, it's perfect