Re: [Gretl-devel] append and sleep

On Thu, 18 Jan 2007, Ignacio Díaz-Emparanza wrote: You now have (in CVS and the Windows snapshot) these things: * You can do "set shell_sync on" to make the shell command work synchronously. This is tested on Linux. Windows requires different code to do that and I've added what I think is suitable code but it's not yet tested. * You can use the "append" command inside a loop. However, these things by themselves will not make the script do all you want it to. The structure of your script is function (list, etc) loop across list members generate transformation using tramo add to dataset with "append" end loop end function # main open data set form list call function on list OK, here's the problem: as you go through the loop inside the function the various linearized series will be added OK, but then when the function exits they will all be destroyed, since they are variables local to the function and are not returned. There are a few possible work-arounds for this, 2 of which I'll mention for reference, and then a "proper fix" which is in place but not yet well tested. workaround 1: have the function process just one series, and return the new series. The caller assigns the new series to an "outside" variable. workaround 2: the function processes several series, packs them into a matrix, and returns the matrix. OK, except that this puts the burden of dealing with a matrix onto the caller. "Proper fix": a function can return a list. As the new series are generated they're added to a list, which is then returned. Up till now functions could not return lists, but it turns out this is not very difficult to implement, so I've done it. When a variable inside a function is referenced in a list that is returned and assigned, that variable is _not_ destroyed on exit from the function. Here's a simple example of how things should be structured. function make_cubes (list xlist) list retlist = null loop foreach i xlist --quiet series $i3 = $i^3 list retlist = retlist $i3 end loop return list retlist end function open data4-1 list xlist = 3 4 list cubelist = make_cubes(xlist) print xlist cubelist --byobs Allin.