Micro-benchmark in Lua for comparing two methods of dealing with varargs

select-test.lua

require 'pl'

local select = select

function sum_select (...)
    local sum = 0
    local n = select('#',...)
    for i = 1,n do
        sum = sum + select(i,...)
    end
    return sum
end

function sum_arr (...)
    local sum = 0
    local n = select('#',...)
    local args = {...}
    for i = 1,n do
        sum = sum + args[i]
    end
    return sum
end

collectgarbage 'stop'

local start_gc, msg_gc

function gc_start (msg)
    if start_gc then
        gc_finish()
    end
    start_gc = collectgarbage 'count'
    msg_gc = msg
end

function gc_finish ()
    print(('%s: mem %7.1f kb'):format(msg_gc,collectgarbage 'count' - start_gc))
    start_gc = 0
end

gc_start 'select'

test.timer('select',1e6,sum_select,1,2,3,4,5,6)

gc_start 'arr'

test.timer('arr',1e6,sum_arr,1,2,3,4,5,6)

gc_finish()