indexing struct

[Mike B.]

Hi All,

Is it possible to loop over a struct with indexing?

For example:
a( 1 ).vec = [ 1, 2, 3 ];
a( 2 ).vec = [ 4, 5, 6 ];

For all structure cells I'd like to get the 1st vector component, so this 
should give
1 4

but

a( : ).vec( 1 ) gives

> error: can't perform indexing operations for cs-list type

Thanks,
Mike.