Thank you for the link, the answer to my question was as in the example you
gave, but with a single argument. The solution to my problem given below
works, but I can't find the answer to the following question. What is the
difference between \dosingleempty and \dosingleargument ?

%%%%%%%%%%%%%%%%%%%%%%%
\unprotect

\definesystemvariable {dt}

\def\setuptitle
  {\dosingleempty\dosetuptitle}

\def\dosetuptitle[#1]%
  {\def\dodosetuptitle##1%
     {\getparameters[\??dt][#1]}%
  \processcommalist[#1]\dodosetuptitle}

\def\placetitle
  {\startalignment[\v!middle]
   \blank[\v!force,2*\v!big]
   \@@dttitle
   \blank[3*\v!medium]
   \@@dtauthor
   \blank[2*\v!medium]
   \@@dtdate
   \blank[3*\v!medium]
   \stopalignment}

\setuptitle
  [\c!title=,
   \c!author=,
   \c!date=\currentdate]

\protect
%%%%%%%%%%%%%%%%%%%%

On Fri, Feb 5, 2010 at 11:29 AM, Wolfgang Schuster <
schuster.wolfgang@googlemail.com> wrote:

> Am 05.02.10 09:03, schrieb Marius:
>
>  Hello all,
>>
>> How do I define the \setuptitlepage and \placetitlepage commands in the
>> environment file? These commands are used as shown in the example below.
>>
>
> Since you do not explain what do you expect from both commands it's not
> possible to give you an answer but you can find on the wiki [1] a example
> for a \setuptitle and \placetitle command which can be copied and used in
> your document.
>
> [1]
> http://wiki.contextgarden.net/Document_Titles#In_ConTeXt:_A_more_advanced_solution
>
> Wolfgang