On Thu, Aug 30, 2012 at 11:16:09AM +0200, Dominick Vanthienen wrote:
> Hi,
>
> I'm trying in the taskbrowser and in rtt_lua to create a variable from a msg like type, eg. motion_control_msgs.JointPositions, which contains two structs which are arrays.
> The typekit was generated using rtt_rosnode create_rtt_msgs functionallity.
>
> var motion_control_msgs.JointPositions a
> = {names = { [ ], size = 0, capacity = 0 }, positions = { [ ], size = 0, capacity = 0 } }
> (btw, it seems to me that you can create a variable of this type with different sizes of 'names' and 'positions')
>
> Since there is no resize option for array like types, the only way to get an array of a certain type is to initialize it with the correct type, but in this case, it is not
> possible in the task browser...
> Is it possible to create this 'resize' method with array like types?
>
> Then the lua case: I tried to create it with
> t=rtt.Variable("motion_control_msgs.JointPositions")
> t:fromtab({names={"a","b"}, positions={0.0,0.0}})

The current "fromtab' does not automatically resize, so you need to
take care of it. Something like below should work:

t.names:resize(2)
t.positions:resize(2)
t:fromtab({names={"a","b"}, positions={0.0,0.0}})

There is however a patch in my ocl-mk for the next release that does
that automatically:

commit 010aae590cf77da7190e9207bab4d4d1d0a40d62
Author: Markus Klotzbuecher <markus [dot] klotzbuecher [..] ...>
Date: Tue May 8 16:13:34 2012 +0200

lua: let [var]fromtab automagically resize vector types

> but this doesn't work either.
> How should I do this?
>
> In the end, I ended up creating a dummy c++ component, with a
> property of the desired type, filled in some values there, created a
> property file from that and loaded that into my rtt_lua code...

Markus