Re: Arithmetic on strings

[Hans Hagen <pragma@...>]

On 13-6-2012 20:14, Roberto Ierusalimschy wrote:
> > Concerning (2): not all types have metatables so boolean is still
> > somewhat of a problem then. (I can live with it.)
>
> We can use the metatables for strings (if at least one argument is
> a string)! This already works both in 5.1 and 5.2:
>
> mt = getmetatable("")
>
> mt.__concat = function (a,b)
>    return tostring(a) .. tostring(b)
> end
>
> print("result: " .. {})     --> result: table: 0x8172130
> print(false .. " x " .. true)  --> false x true

interesting, so what is the trick for

local t = { 1, 2, "test", true }

print(table.concat(t))



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