'rope function called outside of dispatch function or inside coroutine' when using rope:parallel

[propapanda]

I can't seem to get the rope:parallel function to work. Everything I've tried results in the following error:

Error: corope.lua:328: rope function called outside of dispatch function or inside coroutine
stack traceback:
  [C]: in function 'error'
  tests/utils/corope.lua:157: in function 'checkCorrectCoroutine'
  tests/utils/corope.lua:296: in function 'signal'
  tests/utils/corope.lua:328: in function 'errhand'
  tests/utils/corope.lua:106: in function 'update'
  tests/coropetest.lua:6: in function 'update'
  [string "boot.lua"]:464: in function <[string "boot.lua"]:436>
  [C]: in function 'xpcall'

My simple function call for testing looks like this:

bundle(function(rope)
    rope:parallel(
        function()
            print "First"
            rope:wait(0.5)
        end,
        function()
            print "Second"
            rope:wait(1.5)
        end
    )
    print "Last"
end)

Going by the documentation, I would expect it to output:

First
Second
Last

Instead it throws the error message shown above.

Would it be possible to get an example showing how the Parallel function is meant to be used?

[bakpakin]

I have taken a look at your code and added an example in the examples folder. There was a slight problem with the parallel function which I have fixed.

In parallel, each of the functions that runs gets its own new rope, which use should use to control the timing.

bundle(function(rope)
    rope:parallel(
        function(ropea)
            print "First"
            -- Don't do rope:wait(0.5)
            ropea:wait(0.5)
        end,
        function(ropeb)
            print "Second"
            -- Don't do rope:wait(1.5)
            ropeb:wait(1.5)
        end
    )
    print "Last"
end)

While Lua coroutines are powerful, there are some limitations in jumping between them. One can only manipulate a rope within a single coroutine (there is a 1 to 1 correspondence with coroutines and ropes). When trying to wait on the original rope inside the parallel function, you are in a different coroutine (the one corresponds to ropea or ropeb). Fortunately, we can create as many ropes as we want and wait on those ropes.