Re: A Basic Question: A list player

[Christian W. <cwa...@gm...>]

chikitin wrote:
> --The folowing function returns an array containing n elements  
> randomly

> selected from tbl.

No. It performs n random transpositions on tbl.

> Code:
>
> function n_permuter(tbl, n)
>  for i = 1,  n do
>    local a,b = math.random(#tbl),math.random(#tbl)
>    tbl[a], tbl[b] = tbl[b], tbl[a]
>  end
> end

The # operator is new in Lua 5.1, and Pipmak still uses 5.0 (will  
update to 5.1 in version 0.3, whenever that is). In Lua 5.0, you use  
table.getn(tbl). You should have gotten an error message about this.

> ---- here's the player! but doesn't work properly.
>
> function list_playerXL(a,m,bl)
>
>
>  a[1]:play()
>  local ii=1
>
>
> if bl==0 then
>
> pipmak.schedule(.05,
>
>       function()
>
>         repeat
>         if not a[ii]:playing() then
>             if not a[ii+1]:playing() then
>
>                            ii=ii+1
>                            a[ii]:play()
>
>                          end
>                      end
>
>         if a[ii]:playing() then
>                         n = .05
>                      else
>
>                            n = nil
>                   return n
>
>                      end
>             until ii==m-1
>                      end
>          )
> else
>
>      a= n_permuter(a, m)
>      list_playerXL(a, m, 0)
>
> end
> end
>
>
> -- but when i execute the code, it only plays the first sound in the  
> array!

I'm having some trouble understanding that code. Your scheduled  
function only ever returns nil or nothing, and therefore is only run  
once, is that what you want? What's the point of assigning .05 to n  
when that value is never used (the only place where n is used is in  
"return n", and there you set it to nil just before)? (Is the return  
statement placed where you meant to place it? Your indentation is a  
bit odd so it's easy to miss.) Your repeat loop spins a large number  
of times while sounds are playing, using 100% CPU and blocking all  
other Pipmak activity, is that what you want?

Here's how I would clean it up into something that does approximately  
what you want (untested):

function list_playerXL(a,m,bl)
   if bl ~= 0 then
     n_permuter(a, 30)
   end
   a[1]:play()
   local ii=1
   pipmak.schedule(.05,
     function()
       if ii == m then
         return nil
       end
       if not a[ii]:playing() then
         ii=ii+1
         a[ii]:play()
       end
       return .05
     end
   )
end

> I tried list_playerXL(a,6,0). but it plays different number of  
> sounds each
> time!

I'm not sure why it would do that, at a glance, but I don't have time  
to test it or analyze it in detail right now. I'll have a closer look  
tomorrow if you can't figure it out until then.

> I couldn't Attach the file ( 5MB) it was saying that the file is too  
> large
> when i tried to upload it.

Yes, we'd rather not spam all list subscribers with 5MB files. Why is  
it so big, anyway? I'd imagine that you should be able to strip down  
an example project for this to a few dozen KB. If it must be that big,  
then you're better off putting it on some web server or file hosting  
service and posting a link than sending it directly through the list.

   -Christian