TabularX vertical alignment

Question

Since the enumiten Package (and therefore leftmargin=*) doesnt work in custom environments, I was trying to trick a bit, doing the items in a table like this (don't ask..) :

  \documentclass[fleqn,10pt,twocolumn]{article} % Document font size and equations 
  \usepackage{tabularx}
  \renewcommand\tabularxcolumn[1]{m{#1}}
  \newcommand{\localtextbulletone}{{\raisebox{.45ex}{\rule{.6ex}{.6ex}}}}

  \newenvironment{parameters}
      {Parameters:\\
       \tabularx{\linewidth}{>{\raggedright\arraybackslash}p{0.3cm}X@{}}    }
      {\endtabularx}

      \newcommand{\parameter}[2] %Name, Description
  {\localtextbulletone & #1: #2\\}

  \begin{document}
  \begin{parameters}
  \parameter{Test}{This is a long text to illustrate the alignment of the item... 
  blablabla long text long text long text long text long text long text long text long 
  text long text long text}
  \end{parameters}

\end{document}

I needed to set the tabularxcolumn to 'm' instead of 'p' for other tables in my document. In this case I would like to set it back to p, but only in this particular environment so the bullets are top aligned and not centered.

If I try to just do the analoge \renewcommand\tabularxcolumn[1]{p{#1}}inside the environment, latex is not happy. How can I reset the tabularxcolumn just for this environment?

Many Thanks in advance

Answer 1

Just put the \renewcommand line immediately before the \tabularx it will be scoped by the surrounding parameters element.

 \newenvironment{parameters}
      {Parameters:\\
       \renewcommand\tabularxcolumn[1]{m{##1}}%
       \tabularx{\linewidth}{>{\raggedright\arraybackslash}p{0.3cm}X@{}}    }
      {\endtabularx}