Give parts of commands/definitions to a called command (to parse arguments)

Hello,

I want to have two definitions for typesetting vertical and horizontal
vectors.

I thought about this one for vertical vectors:



def vvec
   right body
   { pmatrix strut { Yes }  body }


The body is nor parsed again, so it is not seen as command, when using

     vvec { row col a row col b row col c }

inside @Eq.

Is there a way to parse the body inside the vvec-command?
Or are there other ways to achieve my goal?

I want to have a handy way for typesetting vertical and horizontal vectors.


Ciao,
    Oliver

P.S.: Using '{' and '}' around "body" in the vvec-definition doe snot help,
       other things I tried / experimented with also did not work.