Am 21.05.2013 um 17:41 schrieb Xan <dxpublica@telefonica.net>:

Hi,

I have two enumerations:

\defineenumeration
  [exercici]

You need a different name for the normal enumeration environment, e.g. exercicidefault

  [alternative=serried,text={\startcolor[middlecyan]Exercici\stopcolor},stopper={.\space},left={\bgroup},right={\egroup},width=fit,headstyle=\ss]

\defineenumeration
  [exercicivora]
  [alternative=serried,text={\startcolor[middlecyan]Exercici\stopcolor},stopper={.\space},left={\bgroup\startframedtext[background=screen,frame=off,width=broad]},right={\stopframedtext\egroup},width=fit,headstyle=\ss]

I just want to join into one: when I do \startexercici ...      \stopexercici ConTeXt do the first, and when I pass \startexercici[vora] ... \stopexercici then do the second. That is, 'vora' as optional argument.

How can I achieve that?

You have to write you own version of the exercise environment which chooses one the two enumerations dependent on the argument.

\def\startexercici

  {\dosingleempty\dostartexercici}

\def\dostartexercici[#1]%

  {\edef\currentexercici{#1}%

   \doifelse{\currentexercici}{vora}

     \startexercicivora

     \startexercicidefault}

\def\stopexercici

  {\doifelse{\currentexercici}{vora}

     \stopexercicivora

     \stopexercicidefault}

Wolfgang