9. Coroutines

9. Coroutines

function setup()
    parameter.action('Run_without_coroutine',bigJob)
    parameter.action('Run_with_coroutine',WithCoroutine)
end

function WithCoroutine()
    cos=coroutine.create(bigJobCos)
    coroutine.resume(cos)
end

function bigJob()
    output.clear() --clear print output area
    for n=1,10 do
        --time consuming code here
        for j=1,5000000 do  local x=3.1^4.5 end
        print('completed',n) 
    end
    print('Job done!')
end

function bigJobCos()
    output.clear() --clear print output area
    progress=0 --used for printing status of job
    for n=1,10 do
        --time consuming code here
        for j=1,5000000 do  local x=3.1^4.5 end
        progress=n
        coroutine.yield() 
    end
    progress=-1 --signal end of job
    if cos then cos=nil end --just to be tidy, kill this off
end

function draw()
    if progress then --only report if job is running, ie n is not nil
        if progress>0 then
            print('completed',progress) --print progress of job
            coroutine.resume(cos) --carry on calculating
        elseif progress==-1 then
            print('Job done!')
            progress=nil --to stop any more printing
        end
    end
end