using the same value in PS and lout

[Tamas Papp]

Hi,

I have a particular value that I'd like to use in two different
ways. Say that I 

def length { 0.2 }

and then I use it in

{
...
length cm 0.5 cm lineto
...
} @Graphic { {length}c @Wide 0.5 cm @High }

My problem is that I cannot make lout evaluate length and append c at
the end. I tried {}'s (as I did above) but they don't seem to work. Is 
there any way to solve this?

Regards,

Tamas