Using the argument '...' efficiently

With patch 2.0 and the upgrade to lua 5.1, the '...' arg is much more powerful and less memory intensive than it was previously. here's some handy tips on how to use this new functionality

Hooking
Previously, the ... arg would create a table 'args' if called. This allocated a table into memory, and thus became a source of garbage churn. A very common pitfall of this came from hooking: local f = somefunc somefunc = function(...) -- do some crap return f(unpack(args)) end Now if this function is called often, or there are many hooks like this, there will be a significant hit on performance. With lua 5.1 we can do this hook with no memory wasted local f = somefunc somefunc = function(...) -- do some crap return f(...) end

Post-hooks
The new functionality also allows for a nice clean post hook to be made. In this example we need the first arg passed to the function, and we wish to maintain a full proper hook. That means every arg is passed to the hooked function, and every return from that is returned back from our function. local f = somefunc local ph = function(a1, ...) -- do something with a1  return ... end somefunc = function(a1, ...) return ph(a1, f(a1, ...) end

Iterations
As with hooking, iteration over arbitrary number of args would create a table and thus waste memory. With lua 5.1 we can do this cleanly in a for loop function f(...) for i=1,select("#", ...) do    local x = select(i, ...) -- do something with x  end end

Recursion
Clean recursive functions are simple with ... function r(x, ...) local y = x*x if select("#", ...) > 0 then return y, r(...) else return y  end end